Renal Cell Carcinoma with monosomy 8: A Case Series and Review of the Literature.

OBJECTIVES: Renal cell carcinoma (RCC) is a malignancy commonly encountered by both clinicians and pathologists. Different RCC subtypes are classified based on histologic features, immunohistochemistry profiles, and cytogenetic abnormalities. Accurate diagnosis of subtypes is important as it has prognostic and therapeutic implications. The most common RCC subtype is clear cell renal cell carcinoma (CCRCC); the most frequent genetic abnormalities associated with CCRCC are a deletion of the short arm of chromosome 3 involving 3p21 and mutations involving the Von Hippel-Lindau (VHL) gene. Advances in molecular pathology have identified additional molecular pathways leading to CCRCC. Researchers identified mutations of TCEB-1, monosomy 8, intact chromosome 3 and lack of VHL gene mutations in 4.7% of CCRCC. Additional evidence has been found recognizing RCC with monosomy 8 as a unique RCC subtype by describing cases with similar genetic profiles, non-specific immunohistochemistry, and histomorphology that overlapped with other known RCC types. At the University of Vermont Medical Center (UVMMC), conventional cytogenetics are obtained on all renal neoplasms. Three recent cases of RCC with monosomy 8, normal chromosome 3 morphology, clear cell cytology and non-specific immunohistochemistry profiles were identified. We present these cases to further document this unique subtype and highlight the importance of conventional cytogenetics in the diagnosis of renal cell carcinoma.