Answer: B
Histological Description: There are two slides. The one where there is an adjacent adrenal gland, there is usual chromophobe RCC with raisenoid nuclei with irregular, wrinkled, notched nuclear membrane and perinuclear halos. The cells have a relatively low nuclear to cytoplasmic ratio. Some of the cells have degenerative atypia. This area of the tumor lacks necrosis. There are very infrequent mitotic figures and lacks atypical mitotic figures. On the other slide, the tumor shows increased cellularity, cells with higher nuclear to cytoplasmic ratio, and focal necrosis. There are increased mitotic figures along with atypical mitotic figures. There is extensive extra-renal extension with multiple foci of vascular invasion.

Discussion: On the first slide, the findings are typical of usual Chromophobe RCC, which is not assigned a grade. We add the following note in these cases: “Chromophobe renal cell carcinoma is a well-defined variant that has a significantly better prognosis than conventional (clear cell) carcinoma. While chromophobe renal carcinomas are frequently large (mean diameter was 9.0 cm in one study), two-thirds of them are confined to the kidney at the time of diagnosis. While many of these tumors qualify as Fuhrman (ISUP) nuclear grade 3, the Fuhrman (ISUP) nuclear grading system does not accurately reflect their prognosis. In general, patients with stage pT1 and pT2 chromophobe tumors are almost always cured by surgery, while presentation with pT3 or pT4 disease is rare. Consequently, it is not recommended to assign a Fuhrman (ISUP) nuclear grade to chromophobe renal cell carcinomas (Delahunt B, et al. Fuhrman grading is not appropriate for chromophobe renal cell carcinoma. Am J Surg Pathol, 2007 Jun;31(6):957-60.)” There are a minority of Chromophobe RCCs that are overtly high grade, as in this case. There is no accepted grading system for these cases, and it is appropriate to just diagnose them as “high grade Chromophobe RCC.” The other more common scenario of aggressive chromophobe RCC is when there is a sarcomatoid component, which is assigned Grade 4 based on the sarcomatoid component.