Collecting duct carcinoma of the kidney: Clinicopathological and immunoprofile study of the first reported case in KSA

Abstract

Aim (Background): Collecting duct carcinoma (CDC) is a rare variant of renal cell carcinoma (RCC), which usually presents with an aggressive behaviour. There has been no reported case of CDC from Kingdom of Saudi Arabia (KSA), in the literature; and we report this first case of CDC from Almadinah region, KSA. Materials and methods: The paraffin embedded tissue blocks were retrieved from the archives of the pathology department at a tertiary Hospital in Almadinah. Sections were stained with Epithelial membrane antigen (EMA), CD10, Ki-67, E-Cadherin, p63, Vimentin, CK7 and Pan Cytokeratin antibodies. Results: A 60-year-old male presented with right-flank pain, episodes of painless hematuria and low-grade fever for one month. Abdominal ultrasonography and computed tomography (CT) scan revealed enhancing soft tissue density measuring 4.6 x 6.5 cm in the center of right kidney. The patient underwent right radical nephrectomy. Gross pathological examination revealed a tumour in medullary region of the right kidney with invasive growth pattern. Histologically, the tumour was composed of tubulo-papillary spaces; lined by hobnail cells exhibiting marked cytological atypia and nuclear pleomorphism. Immunohistochemically, the tumor cells were strongly positive for EMA, CK-7, Pan-CK (AE1/AE3), CD10 and E-cadherin. It was focally positive for vimentin<br />and negative for p63. Despite radical nephrectomy and radiotherapy, CDC progressed rapidly with multiple metastases, leading to death of the patient within 24 months of diagnosis. Conclusion: We report the first CDC case from western KSA. Early diagnosis and better treatment options may be helpful for improved prognostic outcome in CDC patients.