Mucinous tubular and spindle cell carcinoma of the kidney - Report of a case with imprint cytologic features

Background Mucinous tubular and spindle cell carcinoma of the kidney is a newly established subtype in the World Health Organization classification. The tumor has a good prognosis, and its diagnosis is clinically important. However, there are no reports of its cytologic features. Here we report the cytologic findings of this rare tumor. Case A 68-year-old female had left-sided abdominal pain, fatigue and hematuria. A large mass in the left kidney was removed. Histologically, the tumor was compatible with mucinous tubular and spindle cell carcinoma. Imprint cytologic examination revealed a large amount of tumor cells arranged in tubular, sheetlike and spindle structures. Some tumor cells showed clear cytoplasm. Nuclear atypia was mild, with occasional distinctive nucleoli. Conclusion The cytologic features of mucinous tubular and spindle cell carcinoma have a varied appearance. It should be included in the differential diagnosis to avoid overtreatment. (Acta Cytol 2006;50:680-682).