Pathology Notes

MUTYH-associated polyposis   Updated: 03/02/2021 © Jun Wang, MD, PhD General features AKA MYH-associated polyposis Autosomal recessive Considered a mild form of familial adenomatous polyposis Biallelic mutation of MUTYH gene (DNA mismatch repair) Less 1% of patients with colorectal cancer Pathogenesis MUTYH mutation results in mutation of other genes , including APC and KRAS Clinical presentations Multiple colon polyps , usually less than 100, by age 50 to 60 Extracolonic presentations Polyps may be seen in other organs, such as stomach and small intestine Osteoma Sebaceous hyperplasia or adenoma , etc Pathological features Primarily adenoma Severe dysplasia at early age Genetic abnormalities MUTYH Diagnosis Suspicious presentations Cumulative 10 or more colorectal adenomas Colorectal adenoma with extracolic features of FAP Genetic testing for MYH Back to intestinal tumors Back to syndromes Back to contents

Serrated Polyposis Syndrome Updated: 02/28/2022 © Jun Wang, MD, PhD   General features Previously called hyperplastic polyposis syndrome More common age 50-60 Increased risk for colon rectal cancer Associated with cigarettes smoking and high BMI Increased risk of colorectal cancer Clinical presentations Usually asymptomatic Endoscopic findings of large or flat polyps Key morphological features Both adenomatous and hyperplasic changes Genetic abnormalities Overall uncommon BRAF: Type1, commonly female smokers KRAS: Type 2, RNF43 Diagnostic criteria More than 5 serrated polyps proximal to the sigmoid colon, at least 2 of these are larger than 1 cm Any serrated polyps proximal to the sigmoid colon in a patient with a first degree relative with serrated polyposis syndrome More than 20 serrated polyps of any size in the colon Treatment Polypectomy, complete removal recommended Colonoscopy every 1-3 years Surgery if treatment/surveillance inadequate First degr

Chediak-Higashi syndrome Updated: 08/03/2020 © Jun Wang, MD, PhD General features Rare Autosomal recessive Lysosomal storage disorder Associated with primary immunodeficiency due to impaired phagocytosis Affects multiple systems Symptoms usually present soon after birth Most patients died before 10 as a result of infection or an accelerated lymphoma like phase Pathogenesis Abnormal intracellular protein transport and pigmentation Chediak-Higashi syndrome genes ( LYST/CHS1 ) mutation Abnormal organelle trafficking and fusion Defective lysosome functions Neutrophils and macrophages with normal phagocytic function but delayed fusion of phagosomes with lysosomes NK cell and T cell cytotoxicity markedly decreased due to defective exocytosis of granules Melanosome defects Clinical features Early presentations Nonpigmented skin , blonde hair, blue eyes (partial oculocutaneous albinism) Recurrent bacterial infections Coagulation defects, usually mild Aden

Meigs syndrome Updated: 05/20/2020 © Jun Wang, MD, PhD General features Triad Benign ovarian tumor, ovarian fibromas most common, may be seen with thecoma , granulosa cell tumor as well Ascites Pleural effusion Ascites and pleural effusion disappear after tumor removal Unclear pathophysiology, probably lymphatic drainage of irritation/secretion associated ascite Diagnosis of exclusion after ovarian cancer ruled out Clinical presentations Associated with ovarian tumor: mass, etc Associated with pleural effusion: Dullness of percussion, tachypnea, etc Associated with ascites: shifting dullness, etc Management Rule out malignancy Symptomatic support Surgical removal of ovarian tumor Back to syndromes Back to contents