A clinicopathological and immunohistochemical study of non-urothelial bladder tumours

Non-urothelial bladder tumors (NUBTs) are uncommon accounting for approximately 10% of the total urinary bladder tumors while 90% are urothelial in origin. There are very limited comprehensive studies on NUBTs.

The objectives of the study were to analyze the clinicopathological and immunohistochemical features of NUBTs.

This is a retrospective study of NUBTs diagnosed over a period of 9 years. Patients' files were retrieved from the archives. Gross and microscopic features were recorded. Simple percentage and frequencies were used to interpret the data.

A total 16 cases (10.8% of all bladder tumors) of NUBT were found. Patients' ages ranged from 19 to 87 years with a male: female ratio of 4.3:1. The most common presenting symptom was gross hematuria (81.2%), and the most common location was posterolateral bladder wall. Muscle invasion was seen in 81.2% of cases, and large areas of necrosis were observed in 62.5%. There were two cases of squamous cell carcinoma, five cases each of adenocarcinoma (four secondary and one urachal) and mesenchymal tumors (four malignant and one benign), two cases of amyloid, and one case each of plasmacytomas and paraganglioma. Large areas of necrosis and muscle invasion were noted in high-grade and advanced staged tumors. In all, 43.7% had poor survival.

NUBTs present with similar clinicoradiological findings; however, their histological features along with immunohistochemistry help in the definite diagnosis. One should be aware of these tumors as they frequently present diagnostic and therapeutic challenge. Most of these neoplasms present at an advanced stage. Large or multicentric randomized controlled studies are needed to know the exact behavior and prognosis of these tumors.