The Utility of Immunohistochemistry in Diagnosing Tubulocystic Renal Cell Carcinoma with Papillary Morphology

Abstract

Tubulocystic renal cell carcinoma (TC-RCC) is a recently recognized, rare but distinct malignant entity. Pathologists have endeavored to completely define its histomorphologic, immunohistochemical and molecular features. Recounted is a case where the diagnosis of TC-RCC was confounded by presence of papillary morphology. Immunohistochemical expression of alpha-methyl acyl-CoA-racemase and vimentin with corresponding negativity for CK7 and CD10, following distinctive gross and microscopic findings, confirmed a diagnosis of TC-RCC. This report demonstrates the strategic value of performing immunohistochemistry studies to establish a diagnosis of TC-RCC especially when unusual histologic features are encountered. Immunohistochemistry continues to be the most practical approach to diagnosis as molecular testing methods, such as next generation sequencing, remain unfeasible in the local setting. Cautious prognostication is required as accounts of recurrence and metastasis continue to emerge.