Mucinous tubular and spindle cell carcinoma of the kidney: Five case reports and review of the literature.

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare and polymorphic tumor, which has been previously considered to be a low-grade malignancy, predominantly occurring in women. To the best of our knowledge, MTSCC with bladder metastasis has never been reported. The current study presents five adult cases of MTSCC that included three male and two female patients. Among the male cases, two were of advanced stage, one with MTSCC and renal chromophobe cell carcinoma with bladder metastasis and the other with MTSCC with invasion of the renal vein. The other three cases with small masses were at an early stage. All five cases had a good prognosis and were without recurrence after several years of follow-up. A 70-year-old male with intermittent gross hematuria, intermittent renal colic, and groin radiation pain for a year (case 1), was incidentally detected to have a left renal density mass by total abdominal enhanced computed tomography scans. In the other four cases, renal masses were found by B-ultrasound. The patient in case 1 underwent a retroperitoneal laparoscopic radical nephroureterectomy with bladder cuff resection and transurethral resection of the bladder tumor, and received gemcitabine hydrochloride via intravesical instillation therapy plus cisplatin chemotherapy every 3 months. The patient in case 2 underwent an open left radical nephrectomy and renal pedicle lymph node dissection. The other three patients underwent a laparoscopic radical nephrectomy. All five patients had no recurrence or new metastasis in other organs after follow-up. In conclusion, the incidence of MTSCC in men and women is not as disparate as reported in previous publications. The characteristics of the images of the five adult cases in the present study showed a considerable consistency, with only minor differences. The malignancy and prognosis of MTSCC are still controversial, and thus inclusion and review of more cases is required to reach a definite final conclusion. Sunitinib and gemcitabine chemotherapy in combination with cisplatin may be effective for the therapy of MTSCC patients with metastasis, but a larger range of treatments needs to be identified.