23 June 2022: Textbook Updates

We have posted updates of the following topics:

Adrenal gland & paraganglia > Other nonneoplastic > Ectopic adrenal tissue
by Yuto Yamazaki, M.D., Ph.D., Hironobu Sasano, M.D., Ph.D.
Topic summary: Nests or foci of adrenal tissue detected in various locations of the body distant from the eutopic adrenal glands; sometimes fused with liver or kidney, sharing a common capsule. Also termed heterotopic adrenal tissue or adrenal rests. Detected in both pediatric and adult subjects. Identified in retroperitoneal, pelvic or groin areas. Considered to be due to the abnormality of fusion or migration of adrenal tissue during gestation. No treatment is required unless a neoplasm has developed in the ectopic tissue.

Liver & intrahepatic bile ducts > Drug / toxin induced hepatitis > Drug / toxin induced hepatitis (DILI)-general
by Anthony W.H. Chan, M.B.Ch.B.
Topic summary: Liver injury associated with exposure to certain drugs or toxins. Diagnosis is based on the likelihood of DILI: time to onset, time to recovery, clinicopathological phenotype, exclusion of other causes, potentially offensive drug / toxin being a known cause of liver injury, and response to re-exposure. 10 – 20/100,000 based on prospective population based studies. 5 – 20% may develop chronic DILI. Most patients recover spontaneously after withdrawal of offensive agent.

Prostate gland & seminal vesicles > Inflammation > Granulomatous lesions
by Y. Albert Yeh, M.D., Ph.D.
Topic summary: Uncommon entity of inflammation with formation of granuloma(s) in the prostate. Classification includes nonspecific granulomatous prostatitis, infectious granulomas, postsurgical granulomas, systemic granulomatous prostatitis, xanthogranulomatous and malakoplakia prostatitis. 18 to 86 years, mean and median age of 62 years. Diagnosis: chronic granulomatous inflammation by histopathological examination of the prostate. Treatment: Warm sitz baths, fluids and antibiotics (if there is a urinary tract infection) for nonspecific granulomatous prostatitis.

Stains & CD markers > CEA / CD66e
by Valeriya Skorobogatko, B.A., Brandon Umphress, M.D.
Topic summary: Glycosyl phosphatidyl inositol (GPI) cell surface anchored glycoproteins that function as a ligand for various selectins. Usually considered an epithelial marker with expression in various adenocarcinomas. Normally detected in glycocalyx of fetal epithelial cells. Serum CEA is associated with colorectal carcinoma; preoperative levels can be associated with advanced or metastatic disease and poorer prognosis. Breast carcinoma: 88.3% specific and 46.2% sensitive for diagnosis of metastatic disease.

Testis & paratestis > Germ cell tumors > Choriocarcinoma
by Alyssa Thompson, B.S., Debra L. Zynger, M.D.
Topic summary: Choriocarcinoma is a malignant nonseminomatous germ cell tumor (GCT) composed of trophoblastic cells with associated hemorrhage. Mixed germ cell tumor with choriocarcinoma component has better outcome than pure choriocarcinoma. Testicular GCT with choriocarcinoma affects men aged 20 – 39, with a median age of 29. Patients with beta hCG > 50,000 IU/L have a 5 year survival of 48%. Unlike other testicular GCT, chemotherapy may be indicated prior to a tissue diagnosis in patients with radiologic findings and a serum hCG > 50,000 mIU/mL.

16 June 2022: Textbook Updates

We have posted updates of the following topics:

Bone marrow neoplastic > Bone marrow – plasma cell and lymphoid neoplasms > B lymphoblastic leukemia/lymphoma with recurrent genetic abnormalities > Therapy related B ALL
by Sharon Koorse Germans, M.D., Jesse Manuel Jaso, M.D.
Topic summary: B lymphoblastic leukemia / lymphoma arising after cytotoxic or radiation therapy for a prior malignancy. No distinct morphologic or immunophenotypic features but is commonly associated with KMT2A rearrangement, del(5 / 5q), del(7 / 7q), hypodiploidy, TP53 mutation and BCR::ABL1 rearrangement. Estimated to occur in 1 – 10% of patients who receive cytotoxic / radiation therapy as primary therapy or in preparation for hematopoietic stem cell transplant. Previously mentioned cytogenetic abnormalities, as well as prior exposure to mutagenic agents, confer a worse prognosis when compared to de novo disease.

Laboratory Administration & Management of Pathology Practices > Qualifying board topics > Finance > Laboratory budgeting
by Duy K. Doan, M.D., Lewis A. Hassell, M.D.
Topic summary: Budget is a detailed plan outlining expenses (costs) and revenues (incomes); it is also called a financial plan, a map to get where we intend to go. Operational budget provides a plan of day to day expenses and revenues; capital budget provides a plan for long term upgrades and improvements. Ways of budgeting include (but are not limited to) the following: pro forma budgeting, zero based budgeting, priority based budgeting, activity based budgeting and flexible budgeting. Budget is the internal reporting tool that management uses to control expenses and make decisions; the budget variance analysis is performed periodically, at least monthly.

Lymphoma & related disorders > Mature B cell neoplasms > Large B cell lymphomas-special subtypes > Plasmablastic lymphoma
by Abhilasha Ghildyal, M.D., M.P.H., Julio Poveda, M.D.
Topic summary: Aggressive large B cell lymphoma with plasmablast / immunoblast morphologic features with plasma cell differentiation, usually in association with immunodeficiency. Predominantly occurs in extranodal sites (most common in oral cavity). Mostly occurs in adults with HIV infection or with iatrogenic immunosuppression. Prognosis is unfavorable; median survival is 6 – 12 months. Newer treatment modalities using V-EPOCH (bortezomib with etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) have shown increased survival.

Placenta > Nonneoplastic placental conditions and abnormalities > Infectious > Acute chorioamnionitis
by Andrew P. Norgan, M.D., Ph.D., Drucilla J. Roberts, M.D.
Topic summary: Acute chorioamnionitis is defined by the presence of acute inflammation (neutrophils) within the chorion or amnion (or both) of the extraplacental membranes or chorionic plate (maternal inflammatory response [MIR]), with or without acute inflammatory cell extravasation from the umbilical cord vasculature or chorionic plate vessels (fetal inflammatory response [FIR]). More common in younger, nulliparous women. Unfavorable factors: necrotizing chorioamnionitis; fetal inflammatory response. Treatment: maternal and neonatal antibiotic therapy.

Stains & CD markers > Cytokeratin AE1 / AE3
by Mieke R. Van Bockstal, M.D., Ph.D.
Topic summary: Mixture of 2 different clones of anticytokeratin (CK) monoclonal antibodies (AE1 and AE3), which functions as a broad spectrum cytokeratin marker. Immunoreactivity is observed in epithelia and most carcinomas (i.e., tumors of epithelial origin), with cytoplasmic and membranous positivity. Used to confirm or rule out epithelial nature of tissue, tumors or components of tumors; as such, usually not performed as a standalone immunohistochemical analysis but rather used as part of a panel of immunohistochemical stains to avoid misinterpretation.

13 June 2022: Textbook Updates

We have posted updates of the following topics:

Colon > Inflammatory bowel disease > Ulcerative proctitis
by John D. Paulsen, M.D., Alexandros D. Polydorides, M.D., Ph.D.
Topic summary: Subgroup of idiopathic ulcerative colitis wherein the extent of disease is anatomically limited to the rectum (i.e., distal to the rectosigmoid junction). Diagnosis is based on constellation of symptoms, endoscopic findings, histopathology and exclusion of alternative diagnoses. Factors associated with poor outcomes in adults include young age of onset (< 40 years), nonsmokers and ex smokers, deep ulcerations. Treatment same as ulcerative colitis. Because disease in ulcerative proctitis is limited to within 15 – 20 cm of the anal verge, medical therapies (such as mesalamine) may be administered topically (i.e., by suppository or enema).

Ear > Middle ear and inner ear tumors – benign / nonneoplastic > Cholesteatoma
by Kelly Magliocca, D.D.S., M.P.H.
Topic summary: Cholesteatoma is a benign, nonneoplastic destructive lesion in the middle ear or mastoid, most commonly unilateral. Cystic strips of nonneoplastic, nondysplastic keratinizing squamous epithelium, with a prominent granular layer, keratin debris and background stromal inflammation. Annual incidence ranges between 3 – 14 per 100,000 children and 9.2 – 13 per 100,000 adults. Prognosis and potential for complications influenced by elements such as ossicular chain status, ossicular chain reconstruction, extension of cholesteatoma, labyrinthine fistula, infection or abscess, cranial nerve dysfunction. Treatment of cholesteatoma is surgical.

Gallbladder & extrahepatic bile ducts > Extrahepatic bile duct tumors > Traumatic neuroma
by Elaina Daniels, M.D., Naziheh Assarzadegan, M.D.
Topic summary: Nonneoplastic, disorganized proliferation of normal nerve components at the site of previously damaged peripheral nerves. Commonly seen after gallbladder surgery (i.e., cholecystectomy). No predilection for gender or age. Most are asymptomatic without any specific physical examination findings; can present with right upper quadrant pain, obstructive jaundice, ascending biliary cholangitis (upper abdominal pain, fever, jaundice) and mass. Favorable prognosis. Surgical resection is curative.

Laboratory Administration & Management of Pathology Practices > Qualifying board topics Safety > Patient safety
by Anoshia Afzal, M.D., Lewis A. Hassell, M.D.
Topic summary: Patient safety involves prevention of errors and adverse effects. Promoting a just culture; preventing / reducing pre-analytic, analytic and postanalytic errors; using tools and technology to evaluate and improve patient safety. Spaghetti diagrams or workflow charts can be created in order to maximize the utility and efficiency of work space. A quality indicator portfolio has been offered by College of American Pathologists (CAP), which is called the Q probes program, including the Q track program. Transparency and a team approach should be encouraged whenever an error occurs.

Stomach > Dysplasia > Dysplasia
by Kyra Berg, M.D., Teri A. Longacre, M.D.
Topic summary: Gastric dysplasia is a precursor lesion to gastric adenocarcinoma; it can be flat, polypoid (adenoma) or arise on the surface of an existing nondysplastic polyp. Classified into low and high grade. Male predominant; higher incidence in Asia, Eastern Europe and South America. High grade dysplasia is associated with a much higher rate of progression to adenocarcinoma. Treated with endoscopic submucosal resection or endoscopic submucosal dissection.

9 June 2022: Textbook Updates

We have posted updates of the following topics:

Bone & joints > Chondrosarcoma > Clear cell chondrosarcoma
by Borislav A. Alexiev, M.D.
Topic summary: Clear cell chondrosarcoma is a low grade malignant cartilaginous epiphyseal neoplasm characterized by lobules of cells with abundant clear cytoplasm. Presence of woven bone and osteoclast-like giant cells. Lesion most commonly occurs in adults, generally in the third or fourth decade. Prognosis of clear cell chondrosarcoma is excellent when treated adequately with wide surgical resection, with 10 year disease survival approaching 90%. Wide en bloc resection with clear margins is usually curative.

Bone marrow neoplastic > Bone marrow – neoplastic myeloid > MDS / MPN > Juvenile myelomonocytic leukemia
by Arti Easwar, M.D., Alexa J. Siddon, M.D.
Topic summary: Clonal proliferation of (predominantly) granulocytic and monocytic precursors in children, with < 20% blasts in blood and bone marrow. Approximately 75% of cases occur in children less than 3 years old. 10% of cases are associated with neurofibromatosis 1 and deletion of NF1 gene. According to WHO, low platelet counts, age at diagnosis greater than 2 years and high HgF levels are clinical predictors of shorter survival. Stem cell transplantation is recommended early in disease in patients with PTPN11, KRAS or NF1 mutations; deferred in patients with CBL or NRAS (germline) mutations (mainly due to spontaneous regression of JMML).

Molecular markers > PML::RARA
by Megan Parilla, M.D.
Topic summary: Fusion of 2 genes: PML, which encodes promyelocytic leukemia protein; RARA, which encodes retinoic acid receptor alpha. Found in 98% of acute promyelocytic leukemia (APL) cases and has not been described in other neoplasms. PML::RARA fusions are most commonly the result of a balanced translocation between chromosome 15 and chromosome 17, although the fusion may be the result of more complex or cryptic rearrangements between the 2 genes. PML::RARA fusion is diagnostic of APL. With prompt treatment using ATRA (an active metabolite of vitamin A), usually in combination with ATO, approximately 95% of all APL patients reach complete molecular remission and are considered cured from disease.

Stains & CD markers > Calretinin
by Nick Baniak, M.D.
Topic summary: Calcium binding protein. Nuclear and cytoplasmic staining. Used primarily in the diagnosis of Hirschsprung disease and to confirm sex cord stromal or mesothelial lineage. Function is not clearly understood but it is thought to act as a buffer or sensor of intracellular calcium ions. Used to differentiate (as part of a panel) pleural mesothelioma (positive) from lung adenocarcinoma (negative). Confirms mesothelial origin in pleural or peritoneal specimens. Used as part of a panel in diagnosing cervical mesonephric carcinoma.

Transfusion medicine > Blood donation > Donor collection
by Evelyn M. Potochny, D.O., Melissa R. George, D.O.
Topic summary: Therapeutic blood products may be collected as whole blood and processed into components or collected by apheresis for the targeted component(s). Whole blood collection may proceed to postcollection manufacture of individual components through centrifugation, the addition of preservatives / storage solutions and appropriate labeling. Donor screened to identify whether blood donation will be safe for the individual and to ensure safety of the blood product for transfusion recipients. Whole blood collection: roughly 45 – 60 minute process for screening, collection and observance for postdonation adverse events.

6 June 2022: Textbook Updates

We have posted updates of the following topics:

Bone marrow neoplastic > Bone marrow – plasma cell and lymphoid neoplasms > Plasma cell neoplasms > Plasma cell myeloma (multiple myeloma)
by Meryem Terzioglu, M.D., Genevieve M. Crane, M.D., Ph.D.
Topic summary: Bone marrow based, multifocal plasma cell neoplasm usually associated with a monoclonal immunoglobulin (M protein) in serum or urine and evidence of organ damage related to the plasma cell neoplasm. Diagnosis requires synthesis of clinical, laboratory, radiologic and histologic findings. Twice as frequent in African Americans compared to Caucasians. Usually incurable with median survival of ~5.5 years with a 5 year survival rate of 54%. Updated diagnostic criteria from the International Myeloma Working Group to initiate therapy, including sensitive imaging, may help identify patients who would benefit from treatment before end organ damage occurs.

Placenta > General > Grossing
by Waleed Khan, M.D., Sanjita Ravishankar, M.D.
Topic summary: This topic describes how to gross specimens obtained from placental deliveries. Placenta should always be grossed with knowledge and context of the clinical history. Placental examination in the fresh state is highly preferable to formalin fixed specimens; however, not all institutions may be able to accommodate this preference. While placentas should be grossed fresh, sections may be difficult to cut to the appropriate thickness to allow for adequate fixation and processing.

Placenta > General > Grossing-products of conception
by Sanjita Ravishankar, M.D.
Topic summary: This topic describes how to gross specimens obtained from products of conception specimens (dilation and curettage or dilation and evacuation with or without fetal parts). Purpose of examination: identify chorionic villi or implantation site to confirm the presence of intrauterine pregnancy; evaluate villous morphology and identify abnormalities, including gestational trophoblastic disease (i.e., molar pregnancy). Sections to obtain: representative chorionic villi, membranes, implantation site and decidua.

Stains & CD markers > CD117
by Leonie Frauenfeld, M.D., Christian M. Schürch, M.D., Ph.D.
Topic summary: Proto-oncogene activated in gastrointestinal stromal tumors (GISTs). Highlights mast cells (normal and abnormal) in the assessment of mast cell neoplasms. Has activating or gain of function mutations in most GISTs, often at exon 11, less often at exons 9 and 13. Cytoplasmic staining. Uses by pathologists: confirming diagnosis of GIST, staining of mast cells, staining of myeloid stem cells (myelodysplastic syndrome [MDS], acute myeloid leukemia [AML]: estimating quantity of blasts).

Stomach > Other nonneoplastic > Reactive (chemical) gastropathy
by Tiffany Sheganoski, D.O., Aaron R. Huber, D.O.
Topic summary: Gastric mucosal pattern of injury induced by endogenous (bile / pancreatic reflux) or exogenous (chronic use of nonsteroidal anti-inflammatory drugs [NSAIDs], acetylsalicylic acid, ethanol or chemotherapeutics) agents. Histology is characterized by foveolar hyperplasia, mucin depletion in surface epithelial cells and lamina propria expansion by fibromuscular and capillary hyperplasia. No known geographic variation in the United States. Insult to gastric surface epithelium results in excessive cellular exfoliation, leading to foveolar hyperplasia. Prognosis is good and recurrence rate is generally low with removal of offending agent.

2 June 2022: Textbook Updates

We have posted updates of the following topics:

Bone & joints > Arthritis > Calcium pyrophosphate crystal deposition disease
by Sarosh Moeen, M.B.B.S., Madiha Bilal Qureshi, M.B.B.S., Nasir Ud Din, M.B.B.S.
Topic summary: Calcium pyrophosphate crystal deposition (CPPD) is characterized by calcium pyrophosphate dihydrate crystal accumulation in extracellular cartilage matrix, synovium and joints. Most common crystalline arthropathy. Affects the elderly; M = F. Acute calcium pyrophosphate arthritis is self limited; resolves within days to weeks of treatment. Treatment is aimed at decreasing inflammation and limiting pain; options include joint aspiration, NSAIDs, colchicine, intra-articular and systemic glucocorticoid administration, IL1 receptor antagonists, excision and reconstruction.

Bone & joints > Undifferentiated / poorly differentiated small round / spindle cell tumor > BCOR::CCNB3 sarcoma
by Kemal Kösemehmetoğlu, M.D.
Topic summary: Undifferentiated round cell sarcoma characterized by BCOR::CCNB3 rearrangement (previously Ewing-like sarcoma). Sheets or fascicles of round and spindle cells forming whorls and hemangiopericytic patterns, usually within a myxoid background. Predominantly arises from the bones of children and young adult males (mean age is 15; M:F = 3.1). 5 year overall survival is 75%; disease free survival is 70%. Treatment: neoadjuvant chemotherapy with Ewing regimen followed by surgery or radiation for local control.

Breast > Noninvasive lobular neoplasia > Lobular carcinoma in situ (LCIS) classic
by Jasmine Vickery, M.D., Anna Biernacka, M.D., Ph.D.
Topic summary: Noninvasive, neoplastic proliferation of small, uniform, dyscohesive cells, which originates in the terminal duct lobular unit (TDLU) and fills and distends most of the acini of the involved lobule. Hallmark feature is loss of cellular cohesion due to dysfunctional E-cadherin catenin axis. Identified in 0.5 – 3.6% of benign breast biopsies and in 1.8 – 2.5% of all breast biopsies. LCIS is both a risk factor for and a nonobligate precursor of invasive breast carcinoma. Excision is not recommended after incidental diagnosis of classic LCIS by percutaneous image guided core needle biopsy, as the risk of finding invasive carcinoma on excision is very low (< 5%).

Colon > Infectious colitis > Histoplasmosis
by Bindu Challa, M.D., Ashwini Kumar Esnakula, M.D., M.S.
Topic summary: Histoplasmosis is an invasive mycosis caused by inhalation of the spores of dimorphic fungi Histoplasma capsulatum. Distal ileum and cecum are most commonly affected, followed by the rectum and descending colon. Occurs widely but is highly endemic in Ohio, Mississippi river valleys and Latin America. Prognosis is good after early and aggressive treatment; the disease is fatal if remains untreated. According to the Infectious Diseases Society of America, clinical guidelines for the treatment of GI histoplasmosis without CNS involvement: amphotericin B (300 mg/kg daily) for 1 – 2 weeks followed by oral itraconazole (200 mg 3 times daily for 3 days and then 200 mg twice a day for a total of at least 12 months).

Stains & CD markers > PAS (Periodic acid-Schiff)
by Monika Vyas, M.D., Jonathan E. Zuckerman, M.D., Ph.D., Nicole K. Andeen, M.D., Patricia Tsang, M.D., M.B.A.
Topic summary: A special stain, not an immunostain. Substances with nearby glycol groups or their amino or alkylamino derivatives are oxidized by periodic acid to form dialdehydes, which combine with Schiff reagent to form an insoluble magenta compound. Stains basement membrane (normal and in tumors), glycogen, some mucins and mucopolysaccharides. Routine stain in brain (with Luxol fast blue), cornea, kidney, liver (glycogen stains strongly for PAS without diastase) and skeletal muscle specimens for nontumor pathology. Breast cytology: PASD positive cells with internal structure and producing nuclear indentation, particularly in dissociated or atypical cells, correlate with malignant histology.

26 May 2022: Textbook Updates

We have posted updates of the following topics:

Microbiology & parasitology > Gram negative bacteria > Fusobacterium necrophorum
by Thomas Cotter, D.O., Hasan Samra, M.D.
Topic summary: Gram negative anaerobe; common oropharyngeal pathogen. Most common causal agent of Lemierre syndrome; oropharyngeal infection leads to septic thrombophlebitis of the internal jugular vein. Demographic: previously healthy adolescents and young adults, ages 14 – 24; M:F = 2:1. Trends: dramatic increase of Lemierre syndrome in last several decades. Treatment: Antibiotics – beta lactam agents (penicillins), metronidazole; surgery – debridement and drainage of abscesses.

Penis & scrotum > Dysplasia / carcinoma in situ > Bowenoid papulosis
by Heather Jones, M.D., Liwei Jia, M.D., Ph.D.
Topic summary: Human papillomavirus (HPV) related proliferation of atypical basaloid and koilocytic cells; characteristically involves the anogenital skin and mucosa. Typically presents as solitary or multiple small pink, brown or violaceous papules or plaques on the penis or other sites. Young, sexually active males (on average, late 20s to early 30s). Overall, favorable prognosis, although recurrence is common following conservative treatment. Conservative treatment modalities include carbon dioxide laser vaporization, cryotherapy, electrocoagulation, 5-aminolevulinic acid mediated photodynamic therapy, excisional surgery, 5-fluorouracil and topical imiquimod cream 5%.

Skin nontumor > Infestations > Demodex
by Bethany R. Rohr, M.D., Eric W. Hossler, M.D.
Topic summary: Demodex mites are commensal organisms that are occasionally implicated in inflammatory skin disease. Pathogenic with overgrowth or immune reaction causing rosacea or folliculitis. Prevalence increases with age; M > F. 2 species on humans: D. folliculorum and D. brevis. Possible association with neutrophilic sebaceous adenitis. Treatment: topical sulfur compounds, permethrin, ivermectin, topical metronidazole, topical dilute camphor oil with oral metronidazole, benzyl benzoate (not available in US), lindane, crotamiton, demodectic frost treatment.

Soft tissue > Fibroblastic / myofibroblastic > EWSR1-SMAD3 positive fibroblastic tumor
by Michael Michal, M.D., Ph.D.
Topic summary: Recently characterized, locally aggressive fibroblastic mesenchymal tumor with only 15 cases reported so far. Extremely rare, fusion defined, soft tissue tumor, so far described only on the extremities, with a strong predilection for acral parts. Wide age range (1 – 68 years); M:F = 1:4. Small, painless, infiltratively growing tumor located in the dermis / subcutis. Negative margin status seems to affect the likelihood of recurrence. Complete excision seems to be curative.

Uterus > Other mesenchymal tumors > Perivascular epithelioid cell tumor (PEComa)
by Jennifer A. Bennett, M.D.
Topic summary: Rare mesenchymal neoplasm with myomelanocytic differentiation that is favored to arise from perivascular epithelioid cells. Best classified as a tumor of uncertain malignant potential since recurrences may arise years after initial diagnosis. Most commonly presents at 40 – 60 years (range: 6 – 79). Diagnosis: rarely made on endometrial sampling. Surgery (hysterectomy, myomectomy) is first line therapy as many are presumed leiomyomas. Chemotherapy and radiation may be administered in patients with metastatic or recurrent disease.

23 May 2022: Textbook Updates

We have posted updates of the following topics:

Lymphoma & related disorders > Mature B cell neoplasms > DLBCL and large B cell lymphomas with high grade features > DLBCL, NOS
by Matthew M. Klairmont, M.D., Christopher Y. Park, M.D., Ph.D.
Topic summary: Large B cell lymphoma with a diffuse growth pattern which does not meet the criteria for other WHO defined large B cell lymphoma categories. Medium to large atypical lymphoid cells. Median age = seventh decade but occurs across all ages. Unfavorable clinical prognostic features: ↑ age, ↑ LDH, Eastern Cooperative Oncology Group (ECOG) ≥ 2, Ann Arbor stage III / IV, extranodal disease, bulky disease. Treatment: R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone); other rituximab based regimens.

Skin nontumor > Dermal granulomatous and necrobiotic reaction patterns > Rheumatoid / rheumatic nodules
by Mahyar Khazaeli, M.D., Kiran Motaparthi, M.D.
Topic summary: Rheumatoid nodules are the most common extra-articular manifestation of rheumatoid arthritis (RA). Most common on pressure points (such as the olecranon process); however, they may occur at other sites, including within the lung and other internal organs. 30 – 40% of all patients with rheumatoid arthritis develop nodules. Multiple subcutaneous nodules, in the presence of rheumatoid factors and in the absence of any joint complaints, firmly suggest a diagnosis of rheumatoid nodulosis. Treatment of rheumatoid nodules is unnecessary because they are often asymptomatic.

Soft tissue > Fibroblastic / myofibroblastic > Calcifying aponeurotic fibroma
by Zoonish Ashfaq, M.B.B.S., Saba Anjum, M.B.B.S., Nasir Ud Din, M.B.B.S.
Topic summary: Rare tumor of children and adolescents, that involves the distal extremities, in association with aponeuroses, tendons and fascia. Infiltrative lesion composed of bland spindle cells within a collagenous matrix. Usually occurs in children < 15 years old. Presents as painless, poorly circumscribed soft tissue swelling of prolonged duration. Benign but locally aggressive; due to infiltrative nature, local recurrences may occur. Complete surgical excision is warranted.

Stains & CD markers > ERG
by Michael Michal, M.D., Ph.D.
Topic summary: Transcriptional regulator ERG is a protein encoded by ERG (ETS family transcription factor ERG), which is located at 21q22. Highly sensitive and quite specific immunohistochemical marker for vascular differentiation, including benign and malignant vascular tumors. Nuclear staining. EWSR1-ERG or FUS-ERG rearrangements are together present in about 5% of Ewing sarcomas. Currently one of the best available markers of endothelial differentiation, including vascular neoplasms, such as hemangioma, hemangioendothelioma, angiosarcoma and Kaposi sarcoma.

Thyroid & parathyroid > Benign thyroid neoplasms > Hyalinizing trabecular tumor
by Virginia A. LiVolsi, M.D.
Topic summary: Neoplasm of follicular cells showing a trabecular growth pattern of large cells with pale to eosinophilic cytoplasm containing stromal hyaline material; the nuclear features show elongation, grooves and intranuclear inclusions. GLIS translocation is unique to this thyroid tumor. Hyalinizing trabecular tumor (HTT) comprises fewer than 1% of thyroid neoplasms, shows a female preponderance > 80% and occurs in adults (mean age 50 years). Overwhelming majority of HTT are benign neoplasms; very rare examples showing capsular or vascular invasion have been reported. Surgery with removal of the affected thyroid lobe is curative.

19 May 2022: Textbook Updates

We have posted updates of the following topics:

Bone & joints > Other nonneoplastic > Tumoral calcinosis
by Tamanna Asghari, M.B.B.S., Madiha Bilal Qureshi, M.B.B.S., Nasir Ud Din, M.B.B.S.
Topic summary: Tumor-like deposits of calcium hydroxyapatite in soft tissue surrounding major joints. Nonneoplastic condition, mimics osteocartilaginous tumors; can be primary (familial or sporadic) or secondary (tumoral calcinosis-like lesions). Usually affects younger age groups in the first and second decades of life. Involves periarticular subcutaneous tissue of large joints. Benign condition with good prognosis. Surgical excision is the primary treatment for sporadic and familial forms.

Bone & joints > Other tumors > Osteofibrous dysplasia
by Muhammad Usman Tariq, M.B.B.S., Nasir Ud Din, M.B.B.S.
Topic summary: Osteofibrous dysplasia (OFD) is a benign fibro-osseous tumor of the pediatric age group with strong predilection for the anterior tibial diaphysis. Usually occurs in first 2 decades of life, without gender predilection and most commonly involves anterior diaphysis of tibia. Most lesions are incidentally found on imaging. Favorable prognosis, tendency to recur, may regress after puberty. Treatment: surgical excision (with or without grafting) or curettage for larger tumors and cases with tibial bowing.

Eye > General > Anatomy & histology-retina
by J. Stephen Nix, M.D.
Topic summary: Specialized nervous tissue of the posterior eye that is responsible for the detection of light. Embryologic derivative of the optic vesicle, which arises from the diencephalon and enables detection of light. Macula: highest density of photoreceptors and ganglion cells, responsible for high acuity vision and identified histologically by an increased number of ganglion cells and increased layer thickness. Light is detected by the rods and cones of the photoreceptor layer and signals are transmitted through the layered retina to the optic nerve. Central retinal artery occlusion: often presents with sudden, painless vision loss and damage to the inner aspect of the retina.

Soft tissue > Fibroblastic / myofibroblastic fibrosarcoma > Myxofibrosarcoma
by Madiha Bilal Qureshi, M.B.B.S., Muhammad Raza, M.B.B.S., Nasir Ud Din, M.B.B.S.
Topic summary: Includes a range of malignant fibroblastic tumors with myxoid stroma, variable pleomorphism and characteristic curvilinear vasculature. Painless, superficial, subcutaneous mass of limbs. Affects elderly in the sixth to eighth decades of life. Complex karyotype with intratumoral heterogeneity and aneuploidy. Prognosis is good when tumor is superficial and low grade. Treatment: complete surgical excision with negative margins – 2 cm margin of surrounding normal tissue / fascial plane / periosteum.

Transfusion medicine > Blood donation > Blood donor testing
by Melissa R. George, D.O., Evelyn M. Potochny, D.O.
Topic summary: Donor testing aims to detect transfusion transmissible disease in donors who have already been qualified through the donor history questionnaire, evaluate vital signs and hemoglobin and conduct a mini physical examination. Donor testing is skewed toward sensitivity over specificity. Pattern by which serologic markers become positive is the basis of blood donor testing; transfusion transmissible illness antigens and nucleic acids are the first detectable markers.

16 May 2022: Textbook Updates

We have posted updates of the following topics:

Colon > Infectious colitis > Amebic colitis
by Blaine A. Mathison, B.S., Bobbi S. Pritt, M.D., M.Sc.
Topic summary: Disease caused by infection of the large intestine with the protozoan parasite, Entamoeba histolytica. Transmission primarily by ingestion of E. histolytica cysts in fecally contaminated food or water (fecal – oral); also by sexual contact (oral – anal). Occurs worldwide but more common in tropical and subtropical regions. Definitive diagnosis of amebic colitis is made by finding trophozoites that have invaded the intestinal mucosa. Amebic colitis is treated with both an amebicidal and luminal agent.

Colon > Diverticular disease > Diverticulosis
by Bindu Challa, M.D., Martha M. Yearsley, M.D.
Topic summary: Anatomic change in the colon characterized by outpouchings of mucosa and submucosa through the muscularis. Diverticulosis can be asymptomatic or symptomatic. Highest incidence in Western world; prevalence increases with age. Occurs in weaker portions of the colonic wall where vasa recta infiltrate the circular muscle layer. Frequently is an incidental finding during colonoscopy. Treatment: symptomatic uncomplicated diverticular disease (SUDD): dietary modifications to increase fiber, use of probiotics has been proposed; antibiotics in acute complicated diverticulitis.

Gallbladder & extrahepatic bile ducts > Extrahepatic bile duct tumors > Biliary intraepithelial neoplasia
by Satyapal Chahar, M.D., Monica T. Garcia-Buitrago, M.D.
Topic summary: Biliary intraepithelial neoplasia (BilIN) is a microscopic, premalignant, noninvasive neoplastic lesion of gallbladder or bile duct. Microscopically flat or micropapillary lesion with low or high grade dysplasia. Approximately 1 – 3.5% of cholecystectomies are found to have incidental BilIN; no gender predilection. Extensive disease, involvement of Rokitansky-Aschoff sinuses and positive margin status increase the risk of recurrence. Most high grade BilIN of gallbladder can be cured by cholecystectomy.

Stains & CD markers > IDH1 (R132H)
by Chunyu Cai, M.D., Ph.D.
Topic summary: Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are metabolic enzymes that catalyze the oxidative decarboxylation of isocitrate to produce α ketoglutarate (also known as 2 oxoglutarate [2OG]), NAPDH and CO2. IDH mutant gliomas have a better prognosis than the IDH wild type counterparts. IDH1 R132H immunostain is widely used in pathology laboratories on brain tumors in order to classify diffuse gliomas and provide prognostic implications. IDH1 (R132H) mutant gliomas show diffuse cytoplasmic reactivity in all tumor cells on IDH1 R132H immunostains.