The differential diagnosis may be sometimes challenging and includes primarily the urothelial (transitional cell) carcinoma and rarely the nephrogenic adenoma
, the paraganglioma and the carcinoid tumours.
The benign lesions include cystitis cystica, cystitis glandularis, von Brunn nests, nephrogenic adenoma
, mesonephric remnant, intestinal metaplasia, and urachal remnant.
1] Nephrogenic adenoma
(also named nephrogenic metaplasia) is a benign entity and a common mimic of adenocarcinoma; this presents a diagnostic challenge in the interpretation of bladder biopsies.
Perhaps the most controversial aspect of nephrogenic adenoma
is its derivation and whether it represents a metaplasia or a benign tumor.
Vesical nephrogenic adenoma
is a rare, benign entity that appears most commonly in middle-aged males.
25,27) Nephrogenic adenoma
is the most important differential diagnosis.
This case is an example of a nephrogenic adenoma
with some unusual morphologic features; however, given the patient's history of previous resections, this is not an unexpected diagnosis.
Although some, such as nephrogenic adenoma
, can be seen in different locations, most are identified in particular organs and, as such, have unique differential diagnostic considerations specific to that organ.
The differential diagnosis of CCA includes nephrogenic adenoma
and other benign reactive processes, as well as primary malignant tumors of the urinary bladder and metastases to the urinary bladder.
The differential diagnosis of micropapillary TCC includes nephrogenic adenoma
and clear cell carcinoma.
Although nephrogenic adenoma
has been reported to result in abnormal urine cytologic test results,[11,12] we found no reference to urine cytologic testing in patients with BPEPs.
may show papillary structures, but the lining cells are usually a single layer of cuboidal, flat, or "hobnailed" cells with no conspicuous cellular atypia.