Contributed by Kate Serdy, MD and Anil Parwani, MD, PhD
The patient is a 34 year-old morbidly obese man who presented with abdominal pain and dysuria. A CT scan was performed and revealed a small nodule on the dome of his bladder. Cystoscopy was performed and demonstrated a 2-3 cm tumor at the bladder dome with purulent discharge. A partial cystectomy was performed.
A partial cystectomy specimen was received, measuring 12.3 x 7.2 x 3.3 cm. A tan-brown, firm, granular, exophytic lesion was identified on the surface of the bladder mucosa, measuring 1.5 x 1.4 x 1.3 cm. The cut surface of the lesion was tan-white and smooth with possible extension into the surrounding adipose tissue (Figure 1).
Histologic examination demonstrates a lesion protruding from the mucosal surface of the bladder wall lined by intestinal-type epithelium (Figures 1 and 2). The lamina propria beneath the lesion shows a desmoplastic reaction (Figure 3). In close proximity to the lesion within the bladder wall is an epithelial-lined dilated cystic space (Figures 4 and 5). Sections deep to the lesion demonstrate an exuberant desmoplastic reaction that extends through the detrusor muscle and into the perivesicular fat (Figure 6). Examination of these areas on higher power show scattered large pleomorphic cells with vesicular nuclei, prominent nucleoli and abundant eosinophilic cytoplasm (Figures 7 and 8). The urothelial mucosa adjacent to the adenoma appears normal, with no carcinoma in situ or other urothelial lesions seen.
A paraffin section immunohistologic stain for pancytokeratin demonstrates reactivity in the infiltrating large pleomorphic cells (Figures 9 and 10). These cells are negative for LCA, CD68 and actin.