Bladder Mass in Elderly Man

Junqi Qian, M.D.

Specimen Type:

Bladder

History:

A 68-year- old man underwent transurethral resection of a mass in the bladder dome. Clinical information is unavailable. Submitted are multiple ovoid fragments of light tan tissue measuring 3.4 x 2.4 x 0.5cm in aggregate.

Pathologic Features:

The tumor is composed of cancer cells with extensive involvement of bladder wall musculature. There is a varied appearance of cancer cells. The most common pattern is the mucinous carcinoma (Fig 1-3). The second most common pattern resembles adenocarcinoma of the colon (Fig 4-6). High-grade poorly differentiated adenocarcinoma is also present.

Differential Diagnosis:

  • Urothelial carcinoma
  • Metastatic colonic adenocarcinoma
  • Urachal adenocarcinoma
  • Diagnosis: Urachal adenocarcinoma

Diagnosis:

Urachal adenocarcinoma is far less common than non-urachal adenocarcinoma of the bladder. Urachal adenocarcinomas arise from the urachus, the fibrous remnant from the embryonic allantoic stalk connecting the umbilicus to the bladder. Urachal remnants are reported to occur most frequently in the bladder dome or posterior wall.

The following criteria are used to classify a tumor as urachal in origin: (1) tumor in the bladder (dome), (2) a sharp demarcation between the tumor and the surface epithelium, and (3) exclusion of primary adenocarcinoma located elsewhere that has spread secondarily to the bladder.

Urachal carcinoma usually involves the muscular wall of the bladder dome, and it may or may not destroy the overlying mucosa. The mass may be relatively small and discrete, but in some cases it forms a large mass invading the retropubic space of Retzius and may extend as far as the anterior abdominal wall.

Microscopically, urachal carcinoma has a varied appearance. Most tumors are mucinous. Nonmucinous type resembles adenocarcinoma of the colon. But other types include colloid carcinoma, signet-ring cell carcinoma, and high-grade poorly differentiated adenocarcinoma.

Although urachal adenocarcinoma may arise from villous adenoma of the urachus, intestinal metaplasia of the urachal epithelium is believed to be the factor predisposing to malignant transformation at this site. Whenever urachal adenocarcinoma or primary adenocarcinoma of the bladder is considered, direct extension or metastasis from colorectal carcinoma must be excluded.

References:

  1. Gopalan A, Sharp DS, Fine SW, Tickoo SK, Herr HW, Reuter VE, Olgac S. Urachal carcinoma: a clinicopathologic analysis of 24 cases with outcome correlation. Am J Surg Pathol. 2009 May;33(5):659-68.
  2. Thomas AA, Stephenson AJ, Campbell SC, Jones JS, Hansel DE. Clinicopathologic features and utility of immunohistochemical markers in signet-ring cell adenocarcinoma of the bladder. Hum Pathol. 2009 Jan;40(1):108-16.