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

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K) is an unusual renal tumor. It is important to increase the recognition of MTSCC-K and improve the level of clinical diagnosis. The current study presents a case of MTSCC-K with clinical, imaging and pathological examination. A 60-year-old female presented to the First Hospital of Jilin University suffering from lumbodorsalgia on the right side for approximately one month, without gross hematuria and fever. Imaging examination by abdominal computed tomography scan revealed a ~6.5×5.0-cm solid mass in the inferior pole of the right kidney. The patient underwent laparoscopic radical resection of the right kidney. Pathological examination showed that the tumor was composed of small, elongated cords or tubules, in a tightly packed arrangement. Myxoid stroma was shown to be interspersed among the tubular cells, and appeared to exhibit slender tubular spindle cell-like structures. Tumor cells were smaller and cube-shaped or oval, with single small eosinophilic nucleoli and low-grade nuclei. Occasionally, necrosis and foam cell infiltration were observed. Myxoid stroma was stained by acidic mucus. Immunohistochemical markers, including CK7, CK19, EMA, Vimentin and P504S (AMACR) showed positive expression in tumoral cells, but the tumoral cells were CD10-negative. The MTSCC-K is a low-grade polymorphic renal epithelial neoplasm, which may be diagnosed by immunohistochemistry. The patients are likely to have an improved prognosis following surgery compared with patients with other renal cell carcinomas.