Mucinous Tubular and Spindle Cell Carcinoma of the Kidney: Touch Imprint Cytologic and Histologic Findings - A Case Report -

The recent WHO classification has recognized mucinous tubular and spindle cell carcinoma (MTSCC) as a distinct entity of renal cell carcinoma, exhibiting a mixed pattern of tubules and a surrounding spindle cell proliferation within a myxoid stroma, with low-grade nuclear features. A 51-year-old woman had an incidentally discovered renal mass. Radiologic examination revealed a large, well defined mass in the lower pole of the right kidney; a right radical nephrectomy was performed. Imprint cytologic smears from fresh surgical specimens showed cellular, cohesive clusters with thick, broad trabecular arrangements and branching structures. On high power fields, the tumor was composed of round-to-oval low-grade nuclei with vesicular chromatin and small nucleoli. The tumor cells had indistinct borders and pale, eosinophilic cytoplasm, In some areas, round-to-elongated tubular structures and spindle cell patterns were noted. Chronic inflammatory cell infiltration was noted, along with a mucinous back-ground and occasional psammoma bodies. Neither significant cytologic atypia nor mitosis was seen.