Imaging analysis of 13 rare cases of renal collecting (Bellini) duct carcinoma patients in northern China: a case series and literature review.

Abstract

Background: Collective duct carcinoma (CDC) is a highly malignant kidney tumor which is rare in clinical. We report our 12-year experience of Collecting (Bellini) duct carcinoma (CDC) and retrospectively analyzed patients and tumour characteristics, clinical manifestations, different imaging characteristics including CT, MRI and PET/CT. Methods: From January 2007 to December 2019, we retrospectively examined all renal tumors and identifed 13 cases of CDC from 3 medical centers in the northern China. All 13 patients underwent CT scan, 8 of whom underwent dynamic enhanced CT scan, 2 underwent PET/CT scan and 1 underwent MRCP examination. The lesions were divided into nephritis type and mass type according to the morphology of the tumors.Results: The study group included 10 men and 3 women, with an average age of 64.23±10.74 years old. Of these 13 patients, the main clinical manifestations include gross hematuria, flank pain or waist discomfort. The mean tumour size was 8.48 ± 2.48 cm. In this group of cases, 6 (46.2%) cases are cortical-medullary involved type, 7 (53.8%) cases are cortex-medullary-pelvis involved type. 11 (84.6%) cases were nephritis type and 2 (15.4%) cases were mass type. The lesions appeared solid or complex solid and cystic on CT and MRI. The parenchymal part of 13 CDC tumors showed isodensity or slightly higher density on unenhanced CT scan. Two patients with PET/CT showed increased radioactivity intake. Evidence of intra-abdominal metastatic disease was present on CT in 9 ( 69.2% ) cases.Conclusions: The Collecting (Bellini) duct carcinoma has its certain imaging characteristics which were different from the other renal cell carcinoma. A renal tumor should be considered as CDC when it locates in the junction zone of the renal cortex and medulla, with unclear border, slight enhancement and metastases in early stage. PET/CT can greatly enrich the key information of diagnosis, surgery and treatment options, which provide significant help to the clinic.