A Case of Abdominal Wall Desmoid Tumor after Radical Nephrectomy for Renal Cancer

A 71-year-old man with a right renal tumor underwent nephrectomy. The procedure was converted from laparoscopy to open surgery due to profound bleeding from the renal vein. Pathological diagnosis was clear cell carcinoma G2pT3b v1 ly1 INFα. Three years after surgery, a 5 cm tumor in the abdominal wall was found on computed tomography (CT). A mild uptake was shown on positron emission tomography/CT and as the tumor was located near the surgical wound, recurrence of the renal cell carcinoma was suspected. However, desmoid tumor was suggested by the pathological examination of the tumor biopsy. En-bloc resection of the mass was carried out and the pathological examination showed an array of proliferating and tangling atypical spindle-shaped tumor cells. Immunohistochemical staining of the tumor cells was positive for vimentin, but negative for CD34, c-kit, and s100. Pathological diagnosis was desmoid tumor. There has been no recurrence so far. Desmoid tumor, despite its extremely low incidence, should be considered in a postoperative neoplasm.