Pathology Notes

Practice questions I Tumors of vessels © Jun Wang, MD, PhD 1. A 2-year-old girl presents with a rapidly growing reddish mass on her left face, covering eye-lid, left side of nose, and upper lip. The mass has small foci of ulceration. Purulent exudates are seen. Microbiology culture of the purulent exudates grows non-hemolytic white raised colonies gram-positive, coagulase-negative cocci that form clusters. These bacteria are sensitive to novobiocin. Biopsy of the lesion reveals packed small channel-like spaces lined by benign flat epithelial cells that is positive for CD31. Scattered neutrophilic and lymphoplasmacytic infiltration is seen. What is the most likely diagnosis? A. Angiosarcoma B. Bacillary angiomatosis C. Capillary hemangioma D. Hemangioblastoma E. Kaposi sarcoma 2. A 1-year-old boy presents with an ulcerated lesion on his right ear. The lesion is a 2.5 cm well-demarcated, red nodule with peripheral telangiectasia and central ulceration. No other abn

Peutz-Jeghers syndrome   Updated: 01/10/2023 © Jun Wang, MD, PhD General features Autosomal dominant with variable penetrance, usually diagnosed in 20’s Markedly increased risk of malignancies of different organs, including gastric type adenocarcinoma of cervix May have Sertoli cell tumor of ovary Genetic abnormalities STK-11 Diagnostic criteria 3+ histologically confirmed Peutz-Jeghers polyps Any Peutz-Jeghers polyp with a family history Characteristic melanotic mucocutaneous pigmentation (lips, oral mucosa, genitalia, digits, palms and soles) with a family history Peutz-Jegher polyp and characteristic mucocutaneous pigmentation Peutz-Jeghers polyp Broad bands of smooth muscle fibers , thicker centrally, with “Christmas tree” appearance Relatively normal glands Back to intestinal tumors Back to syndromes Back to contents

Lynch syndrome   Updated: 11/03/2023 © Jun Wang, MD, PhD General features Hereditary non-polyposis colorectal cancer Autosomal dominant Most common hereditary colorectal carcinoma syndrome 80% of patients develop colorectal carcinoma Increased risk of cancers of endometrium , ovaries, small bowel, stomach , upper urinary tract , and brain, or skin ( Muir-Torre syndrome ) Genetic abnormalities Mismatch repair genes: MLH1, MSH2, MSH6, and PMS2 genes EPCAM: causing methylation and silencing of MSH2 MMRs MutSalpha: Heterodimer of MSH2 and MSH6, rocognizes base-pair mismatches MutLalpha: Heterodimer of MLH1 and PMS2, promote excision of mismatches Diagnostic approach Screening test recommendations  CRC diagnosed at age <50 years Synchronous CRC, metachronous CRC, or Lynch syndrome-associated tumors CRC with the MSI-H histology diagnosed at age <60 years CRC in ≥1 first-degree relative with a Lynch syndrome-related tumor with 1 of the cancers diagnosed at ag

Gardner syndrome   Updated: 03/02/2021 © Jun Wang, MD, PhD General features A variant of familial adenomatous polyposis Clinical presentations Numerous colon polyps Mesentery fibromatosis Bone osteomas Fibromas Epidermal cysts , etc Genetic abnormalities APC Back to intestinal tumors Back to syndromes Back to contents

Familial adenomatous polyposis  (FAP) Updated: 03/02/2021 © Jun Wang, MD, PhD General features Autosomal dominant  Mutation of adenomatous polyposis coli (APC) gene Polyps start growing in teenagers 100% progress to colonic adenocarcinoma, often in teens , most by thirties Higher risk for carcinoma of thyroid, gallbladder, adrenal glands May have desmoid tumors ( Gardner syndrome ) Clinical presentations Numerous colon polyps Polyps may be seen in other organs, such as stomach and small intestine Pathological features Primarily tubular adenoma Severe dysplasia at early age Genetic abnormalities APC Pathogenesis APC mutation associated beta-catenin translocation to nuclei, activating transcriptions Diagnosis Suspicious presentations Cumulative 10 or more colorectal adenomas  Colorectal adenoma with extracolic features of FAP Genetic testing for APC or MYH Back to intestinal tumors Back to syndromes Back to contents

Frequently discussed syndromes ©Jun Wang, MD, PhD Updated 03/02/2021 B Beckwith-Wiedemann syndrome Birt-Hogg-Dubé syndrome C Carney complex Chediak-Higashi syndrome Cowden syndrome D Danys-Drash syndrome DiGeorge syndrome F Familial adenomatous polyposis G Gardner syndrome H Hemolytic-uremic syndrome Horner syndrome Hyper IgM syndrome J Juvenile polyposis syndrome L Li-Fraumeni syndrome Lynch syndrome M Maffucci syndrome Meigs syndrome Muir-Torre Syndrome Multiple endocrine neoplasia  MUTYH-associated polyposis Myelodysplastic syndrome N Neurofibromatosis I Neurofibromatosis II Nevoid basal cell carcinoma syndrome O Ollier Disease P Peutz-Jeghers syndrome Potter syndrome S Serrated polyposis Sezary syndrome   Sjogren syndrome Superior vena cava syndrome T Tuberous sclerosis V Von Hippel-Lindau syndrome W WAGR syndrome Waterhouse Frederichsen syndrome Wiskott

Neurofibromatosis I   Updated: 03/29/2020 © Jun Wang, MD, PhD General features Also called von Recklinghausen disease, NF1 Either autosomal dominant or de novo mutation 5 - 13% develop malignant peripheral nerve sheath tumor 2 - 4 x increased risk of other tumors (childhood CML , ganglioneuroma, meningioma, pheochromocytoma, rhabdomyosarcoma ); acoustic neuroma (schwannoma) , astrocytoma, gastric carcinoid, GIST , glomus tumor , lipoma , optic nerve glioma, Wilm tumor Clinical presentations Multiple neurofibromas (plexiform, solitary) Plexiform neurofibromas relatively specific 6 or more cafe au lait spots over nerve trunks Lisch nodules (pigmented iris hamartomas, majority by age 6) Pathogenesis Neurofibromin defect Resulted in ineffective conversion of RAS to inactive form Genetic abnormality Mutation of NF1 (neurofibromin) at chromosome 17q11.2 Back to soft tissue tumors Back to syndromes Back to contents