Hereditary uterine cancer (UC) is traditionally associated with pathogenic/likely pathogenic germline variants (PGVs) in Lynch syndrome genes or PTEN; however, growing evidence supports a role for other genes that may reveal new clinical management options. In this study we assessed the prevalence and potential clinical impact of PGVs identified in UC patients referred for comprehensive germline genetic testing that combined testing for Lynch syndrome, PTEN, and other cancer predisposition genes.
Prevalence of PGVs in patients referred to a single clinical lab for germline genetic testing with an indication of uterine or endometrial cancer were retrospectively assessed and compared by syndrome type, patient age at testing, and self-reported ancestry. Potential clinical actionability of PGVs was based on established guidelines for clinical management, targeted therapies, and clinical trial eligibility.
PGVs were detected in 13.6% of the cohort (880/6490). PGVs were most frequently observed in Lynch syndrome genes (60.4%) and PTEN (1.5%), with 38.1% in another cancer predisposition gene (i.e., CHEK2, BRCA1/BRCA2). PGV prevalence was similar for patients <50 years and those ≥50 years (15.1% vs 13.2%). Nearly all PGVs (97.2%) were associated with guideline-recommended management, including cascade testing; 60.5% were associated with FDA-approved therapies; and 35.2% were associated with clinical trials.
Focusing germline testing on Lynch syndrome genes and PTEN and limiting testing to patients <50 years of age at diagnosis may overlook a substantial proportion of UC patients who harbor actionable PGVs. Universal comprehensive genetic testing of UC patients could benefit many patients and at-risk family members.

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be \"sporadic\" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.

OBJECTIVE: PTEN hamartoma tumor syndrome (PHTS) is a hereditary disorder caused by germline inactivating mutations of the PTEN gene. PHTS includes Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome. We describe how the peculiar pathologic and immunohistochemical thyroid features lead pathologists to suggest PHTS.
METHODS: A 28-year-old white Spanish woman had a multinodular goiter. Total thyroidectomy was performed after fine-needle aspiration biopsy. Microscopic, immunohistochemical, and molecular analyses of the thyroid lesions were realized.
RESULTS: The thyroid was multinodular, showing one papillary microcarcinoma, five follicular adenomas, three adenolipomas, 46 tiny adenomatous nodules (microadenomas), scattered foci of adipose tissue, and lymphocytic thyroiditis. Tumors were positive for thyroglobulin, thyroperoxidase, pendrin, cyclin D1, and p27 but negative for calcitonin and PTEN. A germline heterozygous deletion of one adenine at nucleotide 827 in exon 8 of the PTEN gene was confirmed. No BRAF, NRAS, or KRAS somatic mutations were detected in the papillary microcarcinoma, follicular adenoma, adenolipomas, or microadenomas. Negativity for PTEN was also found in the colonic tubulovillous adenoma and the storiform collagenoma.
CONCLUSIONS: Pathologists play a crucial role in recognizing pathologic thyroid findings associated with PHTS for selecting patients for genetic testing.