Diagnosis: Nephrogenic adenoma of the urinary bladder.

            Comments: The most typical microscopic feature consists of tubules lined by cuboidal or low columnar epithelium. Cystically dilated glands lined by flattened or hobnail cells or disclosing thyroid-like pattern are also frequently seen. A peritubular hyaline rim of collagen is a common finding (Fig. 5, arrow).