Renal cell carcinoma with leiomyomatous stroma: A case report and a review of the literature of a provisional entity distinct from conventional renal cell carcinoma

Abstract

Renal Cell Carcinoma with Leiomyomatous Stroma (RCCLMS) is a rare renal cancer with indolent behavior and favorable prognosis. We present a case of rare renal cell carcinoma with leiomyomatous stroma in a 49-year-old male, with an incidental finding of a 1.6 cm renal nodule on MRI scan. The patient underwent partial nephrectomy of the left kidney and subsequent histological examination showed an epithelial tumor composed of clear cell cytoplasm with low grade nuclear features, surrounded by an abundant smooth muscle stroma composed of fascicles of spindle cells. Immunohistochemistry revealed the positive reaction of tumor cells for CK7, CD10, CAIX, vimentin and desmin; negative for AMACR. Molecular testing via FISH study shows lack of 3p deletion. Final diagnosis of RCCLMS was made. The aim of this case report is to highlight the importance of awareness of this disease as well as to differentiate RCCLMS from other renal cancers with less favorable prognosis and higher degree of malignancy like clear cell renal cell carcinoma. Keywords: renal cell carcinoma; leiomyomatous stroma; kidney.