Clinicopathological characteristics of kidney mucinous tubular and spindle cell carcinoma.

Kidney mucinous tubular and spindle cell carcinoma (MTSpCC) is a rare renal low-grade pleomorphic epithelial neoplasm featured by tubular and spindle cells with a relatively indolent behavior. This study was designed to clinicopathologically characterize two cases of kidney MTSpCC. Similar to other tumors, the data showed the diagnosis of MTSpCC relies on histological examination. Tumor cells stained strongly for CK19, CK20, and CK7 within the epithelioid component. Whereas evaluating MTSpCC clinically showed no specific symptoms, analyzing MTSpCC microscopically showed multiple elongated tubular branches of tumor cells that are closely arranged in cord-like manner under lightly stained myxoid stroma. MTSpCC also has the spindle cell area; the single tumor cell is small and nucleus round or oval. Immunohistochemical analysis of cytokeratins, electron microscopy, or genetic tests all improves the diagnosis.