Uterine adenomatoid tumors: immunohistochemical characteristics with emphasis on Ber-EP4 immunoreactivity and distinction from adenocarcinoma.
Uterine adenomatoid tumors (UATs) may be difficult to distinguish from metastatic adenocarcinoma, particularly in pelviscopic biopsy specimens, myomectomy specimens, or endometrial samplings. This problem may arise because of the infiltration of vacuolated mesothelial cells between fascicles of prominent smooth muscle, which is a characteristic feature in UAT. This diagnostic difficulty has led to inappropriate surgery as reported in the past. Eleven UATs were studied to clarify the differences between these tumors and metastatic adenocarcinoma. Six of the tumors were grossly indistinguishable from leiomyomas. Histologically, the neoplastic mesothelial cells diffusely infiltrated smooth muscle fascicles in all cases, mimicking the pattern of metastatic adenocarcinoma. Immunohistochemical studies using antikeratin and Ber-EP4 antibodies were positive in the mesothelial component in all 11 and nine tumors, respectively, whereas all 11 UATs were negative using antibodies to carcinoembryonic antigen, CD15, TAG-72, and epithelial membrane antigen. Immunoreactivity using Ber-EP4 was focal, membranous, and usually weak, although a strong signal was present in one case. Immunoreactivity using Ber-EP4 (compared with negativity reported for mesothelial proliferations of other sites) may be related to the unique müllerian characteristic of the female peritoneum. Although nonimmunoreactivity for Ber-EP4 favors a diagnosis of UAT over that of adenocarcinoma, Ber-EP4 immunoreactivity does not exclude UAT.
Otis
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Department of Pathology, Baystate Medical Center, Tufts University School of Medicine, Springfield, Massachusetts 01199, USA.
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D018254:Adenomatoid Tumor / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D001706:Biopsy; D002272:Carcinoembryonic Antigen / Q000276:immunology; D002455:Cell Division; D003937:Diagnosis, Differential; D005260:Female; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D016256:Lewis X Antigen / Q000276:immunology; D008875:Middle Aged; D014594:Uterine Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; C117805:Ber-EP4 monoclonal antibody; D002272:Carcinoembryonic Antigen; D006023:Glycoproteins; D016256:Lewis X Antigen; C047052:tumor-associated antigen 72