The pictured kidney tumor is a “rare bird.” It has a dual cell population and shows characteristic features of emperipolesis and cyclin D1 positivity in large cells. What is your diagnosis? A. Papillary renal cell carcinoma type 1 B. MiT family translocational renal cell carcinoma C. Urothelial carcinoma with squamous differentiation D. Biphasic papillary renal cell carcinoma E. Chromophobe renal cell carcinoma with quamous differentiation
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Answer to last issue’s Case of the Month… A. CDH1 Last month’s case was an intramucosal form (pT1a) of hereditary diffuse gastric carcinoma (HDGC). HDGC accounts for 1–3 percent of all gastric carcinomas (1). Most of these tumors are linked to germline mutations of the CDH1 gene encoding the cell-cell adhesion molecule E-cadherin. Mutations of the CTNNA1 gene encoding catenin alpha-1 account for a small minority of HDGC cases. The other genes listed are not related to gastric cancer. Germline mutation of STK11 is typical of Peutz-Jeghers syndrome, whereas RET mutations are linked to multiple endocrine adenomatosis syndromes. FOXL2 mutations are found in granulosa cell tumors of the ovary. In early stages of HDGC, the tumor presents in the form of small intramucosal foci of signet ring cell carcinoma, or as signet ring cell carcinoma in situ, with or without intraepithelial pagetoid spread into adjacent gastric glands. It is not currently known which intramucosal lesions will progress to highly aggressive, invasive HDGC (2).
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References
- C Oliveira et al., “Familial gastric cancer: genetic susceptibility, pathology, and implications for management”, Lancet Oncol, 16, e60–e70 (2015). PMID: 25638682. RS van der Post et al., “Histopathological, molecular, and genetic profile of hereditary diffuse gastric cancer: current knowledge and challenges for the future”, Adv Exp Med Biol, 908, 371– 391 (2016). PMID: 27573781.
