Huge mucinous tubular and spindle cell carcinoma of kidney: A rare case report and literature review.

Rationale: Mucinous tubular and spindle cell carcinoma (MTSCC) is a variant of renal cell carcinoma newly added to the WHO classification in 2004. It is a rare variant of renal cell carcinoma and sometimes it is not easy to distinguish MTSCC from papillary renal cell carcinoma, chromophobe renal cell cancer, etc. The prognosis of MTSCC is favorable after surgical resection. Patient concerns: A 45-year-old male patient presented with a right renal mass that was detected on ultrasonography incidentally. The computed tomography scan showed a huge homogenous mass with patchy calcification in the central area, and the lesion was slightly enhanced after contrast injection. Diagnoses: According to postoperative pathology, the patient was diagnosed with MTSCC. Interventions: The patient underwent an open transabdominal radical resection of right kidney and right retroperitoneal lymph node dissection. Outcomes: The surgical outcomes were good, and no recurrence or metastasis was observed during the follow-up. Lessons: MTSCC is a rare malignancy of the kidney and the prognosis is usually favorable. Preoperative enhanced CT and MRI can help differentiate MTSCC from other renal tumors, so as to provide a more suitable surgical approach for those who need to retain renal function as much as possible.