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.

Ancillary studies in fine needle aspiration of the kidney

“…Mucinous and spindle cell tumors can have papillary areas, but these are uncommon. The presence of mucin is perhaps the best clue on cytology to this tumor . Finally, metastatic lesions can be papillary, but should have a history of tumor elsewhere; the staining profile will depend on the site of origin.…”

Coomassie brilliant blue G-250 acts as a potential chemical chaperone to stabilize therapeutic insulin

“…Insulin amyloidoma marked by extracellular fibrils at the injection site is a medical condition complicating insulin therapy. 1 The instability of monomeric insulin and its fibrillation also interfere with its manufacture, long-term storage, and pharmaceutical use. 2 Overcoming this problem through inclusion of a chemical chaperone such as small molecule, peptide or macrocycle may abrogate fibrilization in insulin formulations.…”

Nadir Görülen Bir Böbrek Tümörü: Müsinöz Tubuler ve İğsi Hücreli Karsinoma

“…Müsinöz tübüler ve iğsi hücreli karsinoma olgularında 1, 4q, 6, 8p, 11q, 13, 14, 15 kromozomlarında kayıp ve 11q, 17 ve 20q kromozomlarında kazanımlar bildirilmiştir. Genomik hibridizasyon verileri ortaya koymaktadır ki bu tümörlerde papiller renal hücreli karsinomada saptanan 7 ve 17 trizomi saptanmaz1,14,17 .Müsinöz tübüler ve iğsi hücreli karsinoma nadir görülen bir renal epitelyal karsinoma tipidir. Papiller karsinoma ile histopatolojik ve immünohistokimyasal bulgular açısından benzer özelliklere sahip olmasına rağmen prognozlarının farklı olması tümöre doğru tanı konulmasını daha da önemli hale getirmektedir.…”