Unsuspected primary renal urothelial carcinoma with squamous differentiation in a background of long standing renal calculi: A case report

Introduction: Primary upper urinary tract tumors are quite uncommon. Most of these are malignant epithelial tumors out of which 90% are urothelial carcinomas. The majority of patients are male and elderly. Long standing renal calculus is a common etiology. Insidious onset of disease, lack of specific signs and symptoms and the inability of routine radiological investigations to detect tumour areas lead to delay in diagnosis. Aims and Objectives: to study the histo-morphological features of incidental primary urothelial carcinoma of kidney with squamous differentiation. Materials and Methods: formalin fixed, hematoxylin and eosin stained sections of a nephrectomy specimen submitted in the Pathology department of SN Medical College, Agra, were observed microscopically and findings were noted. Result: A nephrectomy specimen was submitted for histopathological examination. Grossly, kidney was severely hydronephrotic with dilated calyces and multiple calculi. No tumour or growth was noted. Histology revealed primary urothelial carcinoma with squamous differentiation. Vascular and perineural invasion was also noted. Hilum showed presence of urothelial carcinoma in situ with dysplasia. Extensive areas of necrosis were also seen. Conclusion: In patients presenting with long standing renal calculi and poorly functioning kidney, urothelial malignancy should be suspected and radiological investigations like CT scan should be done pre operatively. Squamous differentiation is common in urothelial carcinomas and is associated with aggressive disease.