Tubulocystic Carcinoma of the Bile Duct

Tubulocystic carcinoma of the bile duct is extremely rare and has not been reported in the literature. We reported a case of cystic neoplasm of the liver with distinct histopathological features that could not be clearly classified as of either mucinous or intraductal papillary neoplasm. A 68-year-old Japanese patient had a multicystic biliary tumor within the liver. This tumor was detected on follow-up of polymyalgia rheumatica. The exophytic, multicystic, 35 × 50 mm mass was composed of complex tubulocystic structures. We initially suspected cystadenocarcinoma of the liver and performed radical operation. However, pathology ultimately showed it to be very rare tubulocystic carcinoma that derived from the bile duct. We reviewed the literature and describe the process of our differential diagnosis.

Expression of Aldo-keto-reductase 1B1 (AKR1B1) in tubulocytic carcinoma of kidney.

507 Background: Tubulocystic carcinoma of the kidney (TubCC) is a new entity of tumor not listed in the 2004 WHO classification. The tumor comprised tubules forming duct-like structures exhibiting hobnail change, and resembled collecting duct carcinoma (CDC) by immunostaining; thus, this tumor was named low grade CDC. Since then, similar tumors have been reportedly called tubulocystic carcinoma (TubCC)We explored the possibility whether Aldo-keto-reductase-1B1 (AKR1B1), osmoregulatory protein and abundant in collecting duct, can be used as a marker for the pathologic diagnosis of TubCC. Methods: We prepared anti-AKR1B1 monoclonal antibodies, examined expression of AKR1B1 protein in the human normal kidney. Immunohistochemical expressions of AKR1B1 was examined on normal kidney, 4 cases of TubCC, 10 cases of papillary renal cell carcinoma (pRCC), and 10 cases of invasive urothelial carcinoma (iUC). Results: AKR1B1 expression distributed preferentially in the renal medulla and not in the cortex, reflected by its high concentration in medulla (2.12 ±1.35 μg/mg) compared with cortex (0.13 ± 0.03 μg/mg). Immunohistochemically, AKR1B1 was strongly positive in 3 of 4 TubCC cases. AKR1B1 was negative in cases of either iUC or pRCC. Conclusions: Although the present study was small and preliminary, AKR1B1 may be a more specific and potentially useful marker for TubCC. [Table: see text]