title: Mucinous tubular and spindle cell carcinoma of the kidney: Diagnosis by fine needle aspiration and review of the literature.
abstract: Renal mucinous tubular and spindle cell carcinoma (MTSCC) was recently described as a distinct subtype of renal cell carcinoma (RCC) in the 2004 World Health Organization classification of kidney tumors. MTSCC is a rare low grade malignancy with < 100 cases reported in the literature. To the best of our knowledge, there are 5 case reports with a total of 6 patients describing its diagnosis by fine needle aspiration (FNA). All of these cases were diagnosed as conventional RCC on FNA. Subsequent excisions proved them to be MTSCC. We herein report a case in a 67-year-old male. He presented with abdominal pain and was found to have a new colon adenocarcinoma with metastasis to the liver and lungs. The extent of disease made the patient ineligible for surgical excision, and he received chemotherapy. Work-up also revealed a kidney mass which was later biopsied by FNA and core biopsy. The tumor was composed of epithelial and spindled cell components embedded in a myxoid background. It was positive for CK7, AMCAR, vimentin, and epithelial membrane antigen. The tumor was diagnosed as MTSCC. One year later the kidney mass remained stable. However, the patient developed new metastasis to the liver from colonic primary. The kidney mass was not resected. Although rarely encountered in FNA cytology of the kidney, we believe the cytologic features of this tumor are distinctive and are different from conventional and other subtypes of RCC. Therefore, its accurate diagnosis on FNA is possible once pathologists are aware that MTSCC should be considered in the differential diagnosis of kidney tumors.
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Jiang
authors.initials: J
authors.lastname: Huimiao
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Chepovetsky
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Aylin
authors.initials: A
authors.lastname: Simsir
authors.affiliation: Department of Medical Oncology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Cohen
authors.affiliation: Address: Department of Pathology, NYU Langone Medical Center, New York, NY 10016, USA.
authors.forename: Allen
authors.initials: A
authors.lastname: Leung
keywords: Fine needle aspiration; kidney; renal mucinous tubular spindle cell carcinoma