Colonic adenocarcinoma metastatic to the urinary tract versus primary tumors of the urinary tract with glandular differentiation: A report of 7 cases and investigation...

Archives of Pathology & Laboratory Medicine,  Sep 2002  by Tamboli, Pheroze,  Mohsin, Syed K,  Hailemariam, Seife,  Amin, Mahul B

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A Report of 7 Cases and Investigation Using a Limited Immunohistochemical Panel

Objective.-To determine whether a limited immunohistochemical panel can help differentiate metastatic colonic adenocarcinoma from primary enteric-type adenocarcinoma of the urinary tract and urothelial (transitional cell) carcinoma with glandular differentiation, which appear morphologically similar but most often necessitate different treatment protocols.

Design.-We examined lower urinary tract tumors (5 urinary bladder, 2 urethral) from 7 patients with a history of colonic adenocarcinoma. The differential diagnoses in these cases included metastatic colonic adenocarcinoma, primary enteric-type adenocarcinoma of the urinary tract, and urothelial carcinoma with glandular differentiation. An immunohistochemical panel consisting of cytokeratin 7 (CK-7), cytokeratin 20 (CK-20), and villin was evaluated in all cases. Four primary enteric-type adenocarcinomas of the urinary tract and 5 conventional urothelial carcinomas were also studied to compare morphologic features and immunohistochemical staining patterns.

Results.-Of the 7 cases, 6 were determined to be metastatic colonic adenocarcinoma and 1 was diagnosed as a primary urothelial carcinoma with glandular differentia

tion. All 6 metastatic colonic adenocarcinomas, 6 of the 7 primary colonic adenocarcinomas, and all 4 primary enteric-type adenocarcinomas of the urinary tract were CK20 positive (1 was CK-20 negative), villin positive, and CK7 negative. The single urothelial carcinoma with glandular differentiation and all 5 control cases of urothelial carcinoma were CK-7 and CK-20 positive, and villin negative.

Conclusions.-We conclude that (1) villin is expressed in primary enteric-type adenocarcinoma of the urinary tract; (2) in difficult cases, urothelial carcinoma with glandular differentiation can be distinguished from colonic adenocarcinoma because the former is CK-7 positive, CK-20 positive, and villin negative, whereas the latter is CK-20 positive, villin positive, and CK-7 negative; (3) clinical information is essential when evaluating lower urinary tract tumors that are clinically and morphologically similar to enteric-type adenocarcinoma of the urinary tract; and (4) the similar immunohistochemical profiles of metastatic coIonic adenocarcinoma and primary enteric-type adenocarcinoma of the urinary tract may be in keeping with the hypothesis that the latter arise from intestinal metaplasia.

(Arch Pathol Lab Med. 2002;126:1057-1063)

Primary adenocarcinomas of the urinary bladder and urethra exhibit a wide spectrum of glandular differentiation that is histologically subtyped as enteric-type, mucinous (colloid), signet ring cell, clear cell, mixed, and adenocarcinoma not otherwise specified.1 Enteric-type adenocarcinoma of the urinary tract is morphologically indistinguishable from metastatic colonic adenocarcinoma,l 2 but certain features, including the location of the tumor, its growth pattern, and clinical history, have been suggested to be useful for distinguishing metastatic colonic adenocarcinoma from primary enteric-type adenocarcinoma of urinary tract.3 Other tumors that need to be included in this differential diagnosis include urothelial (transitional cell) carcinoma with glandular differentiation4 and tumors arising from accessory paraurethral glands, that is, Cowper and Littre glands in men and Skene glands in women, which may present as urethral masses and are morphologically similar to primary urethral adenocarcinomas.5 An additional consideration in males is extension from prostatic ductal (endometrioid) adenocarcinoma, which may closely resemble metastatic colonic adenocarcinoma. This tumor is immunoreactive for prostate-specific antigen, as are the few reported cases of adenocarcinoma of Skene gland.6 Thus, a host of tumors with a predominant or exclusive glandular morphology may involve the urinary bladder or urethra, and it may not always be possible to distinguish these tumors from one another by routine light microscopy alone. However, it is essential to distinguish them, as they most often require different treatment strategies. To date, no reliable morphologic features or ancillary techniques, such as histochemical or immunohistochemical analyses or electron microscopy, have helped resolve this differential diagnostic dilemma.

We studied urinary bladder and urethral tumors in 7 patients with a prior history of colonic adenocarcinoma to determine what morphologic criteria would help reliably differentiate metastatic colonic adenocarcinoma from primary enteric-type adenocarcinoma of the urinary tract. We also evaluated the usefulness of an immunohistochemical panel consisting of cytokeratin 7 (CK-7), cytokeratin 20 (CK-20), and villin for differentiating between metastatic colonic adenocarcinoma, primary enteric-type adenocarcinoma of the urinary tract, and urothelial carcinoma with glandular differentiation.

MATERIALS AND METHODS

Seven patients with a history of colonic adenocarcinoma and subsequent tumors of the urinary bladder or urethra were studied. In addition, 5 randomly selected cases of high-grade invasive urothelial carcinoma and 4 randomly selected cases of primary enteric-type adenocarcinoma of urinary tract were also studied to compare morphologic patterns and immunohistochemical staining patterns. The latter were determined as primary tumors of the urinary bladder, based on the location of the tumor and lack of evidence of prior or subsequent adenocarcinoma at any other site, including the colon (mean follow-up, 43 months).