Renal Mucinous Tubular and Spindle Cell Carcinoma and 18F-Fluorodeoxyglucose-PET/CT Findings

Abstract

Clinical Practice Points � Mucinous tubular and spindle cell carcinoma (MTSCC) is an extremely rare primary carcinoma of the kidney that develops by malignant differentiation of the loop of Henle, is commonly confused with papillary renal cell carcinoma (RCC), and was classified in 2004 by the World Health Organization as a variant of RCC. � The tumor affects people of all ages, and the female to male ratio is 4:1. � We present a patient with an incidental finding of renal mass in the left kidney. � The patient underwent a transperitoneal radical nephrectomy. The immunohistochemical examination revealed MTSCC. Distant metastasis or local recurrences were not observed at the 36-month follow-up. � The differentiation of MTSCC from RCC and its subtype exhibiting sarcomatoid differentiation using immunohistochemical methods is considerably important to predict the prognosis. Widespread bone and lung metastases have been reported in the subtype exhibiting sarcomatoid differentiation. � Mucinous tubular and spindle cell carcinoma is generally a low grade tumor associated with good prognosis and its definitive treatment is surgical excision.