Oncological Outcomes of Primary Renal Malignancies other than Clear Cell Renal Carcinoma: A Retrospective Study from a Tertiary Centre in Southern India

Abstract

Introduction: A lot of research is available about clear cell Renal Carcinomas (ccRCC). But there are lesser known facts about other subtypes of renal malignancies. With advances in immunohistochemical and cytogenetic techniques, new variants of renal tumours are being increasingly reported. The treatment and prognosis of such rare malignancies is still an enigma. Aim: To analyse the incidence, clinicopathological features, surgical treatment, and survival of non clear cell RCC at the tertiary care centre. Materials and Methods: The present study was a retrospective study in which histopathological reports of 77 nephrectomy specimens who underwent surgical treatment for suspected renal tumours from 2013-2018 were reviewed. Of which 19 (24%) patients had documented uncommon histologic variants of RCC. The clinical, demographic, and histologic characteristics of these patients were analysed, and survival was evaluated. The characteristic light microscopy and immunohistochemical features of these lesions were documented. Results: Mean age was 45 years (21-67 years). Out of 19 patients, 14 (73.6%) were males, and 5 (26.4%) were females. Mean tumour size was 8.8 cm (range 6-36) in the largest dimension. About 17 (22%) patients underwent radical nephrectomy, and 2 (2.5%) were treated with partial nephrectomy. Patients with collecting duct, synovial sarcoma, and primitive Neuroectodermal tumour (PNET) had associated inferior vena caval thrombus and underwent venous thrombectomy. Adjuvant treatment in the form of chemotherapy was instituted in collecting duct, adult Wilms and pure sarcomas. There was no mortality in the papillary carcinoma, and the worst prognosis was encountered in collecting duct carcinoma. Conclusion: Papillary variant had a good outcome as compared to other non clear cell carcinomas. RCC with sarcomatoid variant has a poor prognosis. Variants like renal sarcomas are rare but can be managed by nephron sparing surgeries with adjuvant therapies.