10 February 2022: Textbook Updates

We have posted updates of the following topics:

Appendix > Carcinoma > Pseudomyxoma peritonei
by Alex Placek, M.D., M.Sc., Maryam Kherad Pezhouh, M.D., M.Sc.
Topic summary: Clinical term referring to intraperitoneal accumulation of mucin secondary to mucinous neoplasia. Rupture and intra-abdominal spread of mucinous neoplasms; majority from appendiceal mucinous neoplasm. Pseudomyxoma peritonei (PMP) is a clinical term, not a histologic diagnosis. May be incidental finding at time of laparoscopy or imaging. Rare, approximately 1 – 3 cases per million/year. Considered a malignant condition. Treatment: Cytoreductive surgery with or without HIPEC.

Colon > Polyps > Serrated lesions
by Chien-Kuang Cornelia Ding, M.D., Ph.D., Kwun Wah Wen, M.D., Ph.D.
Topic summary: Lesions and polyps that are characterized by a serrated (sawtooth or stellate) architecture of the epithelium; arises from serrated pathway (BRAF or KRAS mutation). Include hyperplastic polyps, sessile serrated lesions, traditional serrated adenomas and serrated adenoma, unclassified. Hyperplastic polyps: ~30% of all colorectal polyps. Treatment: endoscopic polypectomy; lesions with low risk pathology features: repeat colonoscopy in 5 years, lesions with high risk pathology features: repeat colonoscopy in 3 years.

Nasal cavity, paranasal sinuses, nasopharynx > Inflammatory lesions > Inflammatory sinonasal polyp
by Bin Xu, M.D., Ph.D.
Topic summary: Benign, nonneoplastic polyp characterized by edematous stroma infiltrated by mixed inflammatory cells. Most common type of sinonasal polyp. Occurs in 2 – 10% of population. Defected epithelial cell barrier, increased exposure to bacteria and dysfunctioning host immune system may play a role in the pathogenesis. Recurrence rate is approximately 60% in patients followed for at least 10 years. Medical treatments include nasal corticosteroid and high volume saline irrigation.

Placenta > Nonneoplastic placental conditions and abnormalities > Infectious > COVID-19 placentitis
by Sanjita Ravishankar, M.D., Jonathan L. Hecht, M.D., Ph.D.
Topic summary: Pattern of injury associated with transplacental maternal – fetal transmission of SARS-CoV-2. Vast majority of placentas from mothers infected by SARS-CoV-2 show no specific gross of histologic findings regardless of maternal symptom severity or bulk detection of virus in the placenta. Preterm birth is increased due to maternal compromise in severe COVID but not in women with mild symptoms; stillbirth is increased; fetal transmission through the placenta is rare (1 – 3% of infected pregnant women) and is typically associated with severe maternal disease. Viral testing and close monitoring of newborns is indicated.

Stains & CD markers > CD45 (LCA)
by Elena M. Fenu, M.D., Danielle Lameirinhas Vieira Maracaja, M.D.
Topic summary: Ubiquitous cell surface marker of nucleated hematopoietic cells involved in the regulation and activation of the immune system. Receptor tyrosine phosphatase protein expressed on the cell surface of white blood cells and involved in B and T cell activation and signaling. Different subsets of immune cells express different isoforms of CD45 due to variable exon splicing. Strong expression of CD45 may predict a worse prognosis in certain hematologic malignancies, including pediatric B cell progenitor acute lymphoblastic leukemia and multiple myeloma.

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