8 February 2021: Textbook Updates

We have posted updates of the following topics:

Bone marrow neoplastic > Bone marrow – neoplastic myeloid > Recurrent genetic abnormalities > AML with t(8;21)(q22;q22)
by Sean Gu, M.D., Ph.D., Alexa J. Siddon, M.D.
Topic summary: Caused by a recurrent genetic rearrangement that results in the fusion of RUNX1 and RUNX1TI1; predisposes to acute myeloid leukemia with generally favorable prognosis and high rate of complete remission. Blasts have distinct morphologic and immunophenotypic features, including abundant basophilic cytoplasm containing azurophilic granules with occasional Auer rods and frequent aberrant expression of B cell markers, such as CD19. Typically occurs in younger patients and comprises approximately 1 – 5% of all AML cases. t(8;21)(q22;q22.1) results in fusion of the RUNX1 gene on chromosome 21q22.1 with RUNX1TI1 gene on chromosome 8q22. Diagnosis is established by detection of t(8;21) by real time PCR or cytogenetics. Treatment is typically chemotherapy with induction, followed by intensive cytarabine consolidation.

Kidney tumor > Adult renal cell carcinoma – common > Chromophobe eosinophilic variant
by Timothy Isaac Miller, M.D., M.A., Maria Tretiakova, M.D., Ph.D.
Topic summary: Histologic variant of chromophobe renal cell carcinoma (ChRCC) with at least 80% of cells with eosinophilic cytoplasm. No difference in prognosis compared with classic / mixed chromophobe renal cell carcinoma. In large study case series, 41 – 51% of ChRCC were eosinophilic variant. Pathophysiology is same as classic ChRCC: neoplasm of intercalated cells of collecting duct. Potential presenting symptoms: hematuria, pain, flank mass, anemia, pyrexia, cachexia, fatigue and weight loss. Mass seen on imaging with confirmatory renal biopsy or mass resection. On CT scan, ChRCC more likely to have homogenous enhancement (69%) and can have calcifications (38%). Treatment is typically resection via partial or total nephrectomy, the same as classic ChRCC.

Liver & intrahepatic bile ducts > Noninfectious hepatitis > Glycogenic hepatopathy
by Maryam Aghighi, M.D., Raul S. Gonzalez, M.D.
Topic summary: Hepatomegaly, raised liver enzymes and abundant glycogen in hepatocytes related to uncontrolled diabetes mellitus. Mauriac syndrome: rare phenomenon in type 1 diabetics characterized by excessive hepatic glycogen deposition, elevated liver enzymes, hepatomegaly, obesity, cushingoid features and late puberty. Higher prevalence in diabetic patients, type 1 diabetics. Prolonged hyperglycemia due to uncontrolled diabetes mellitus leads to accumulation of glycogen in hepatocytes, resulting in hepatomegaly and elevation of liver enzymes. Clinical and pathological association is required for diagnosis. Good prognosis with medical treatment; blood sugar control by adjusting insulin and diet.

Ovary > Endometrioid tumors > Endometrioid carcinoma
by Ozlen Saglam, M.D.
Topic summary: Ovarian carcinoma resembling endometrioid adenocarcinoma of the endometrium. Most common ovarian endometrioid tumor. 10% of primary ovarian carcinomas; mean patient age is 55 years. Most common molecular alterations: WNT / beta catenin signaling pathway (CTNNB1 – 53%), PI3K pathway (PIK3CA – 40% and PTEN – 17%). Symptoms include abdominal distention and pain. Stage is the most important prognostic factor. Treatment involves surgery for early stage cancers; adjuvant chemotherapy is associated with survival benefit for patients with inadequately staged and grade 2 stage I cancers.

Prostate gland & seminal vesicles > Atypical / intraductal lesions > Low grade PIN
by Megan L. Brown, M.D., Maria Tretiakova, M.D., Ph.D.
Topic summary: Intraepithelial proliferation along pre-existing ducts and acini with mild atypia, at the lower end of the prostatic intraepithelial neoplasia (PIN) spectrum. Tends to be present in younger men, first appearing in men in their 30s – 40s. Loss of function of tumor suppressors (SPRY1, SPRY2) without losses of PTEN. Elevations in PSA. 20% of patients with low grade PIN had cancer on rebiopsy. No specific treatment recommended, treatment based on higher grade lesions. It is not recommended to include low grade PIN in pathology reports.

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