Mucinous tubular and spindle cell carcinoma of the kidney: A case report and brief review of literature.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare subtype of renal cell carcinoma (RCC), accounting for less than 1% of primary renal tumors. Despite its generally favorable prognosis, accurate diagnosis remains challenging because it overlaps with other RCC variants. The present report describes a case of incidentally detected MTSCC in a patient presenting with elevated low-density lipoprotein. A 39-year-old man presented for evaluation of elevated lipid levels and was incidentally found to have 2 left renal masses on ultrasonography. Computed tomography scan revealed a 26 × 24 mm exophytic lesion in the mid-portion of the left kidney with faint, homogeneous enhancement, and a 7 mm lesion in the upper pole. Magnetic resonance imaging confirmed both lesions with diffusion restriction, suggestive of RCC. Laparoscopic partial nephrectomy was performed. Histopathology examination confirmed MTSCC in the mid-pole lesion and a benign renal tubulopapillary adenoma in the upper pole. The patient's postoperative course was uneventful, and follow-up ultrasonography showed no recurrence. A brief review of the literature identified 5 recent reports encompassing 10 documented cases of renal MTSCC. The distribution by sex was equal, with 5 male and 5 female patients. Tumor occurrence was also evenly split between kidneys, with 5 cases on the right and 5 on the left. The patients' ages varied from 41 to 70 years. Mucinous tubular and spindle cell carcinoma is a rare tumor that may be detected incidentally. Laparoscopic partial nephrectomy may provide an effective, kidney-sparing approach with favorable outcomes.