title: Endosalpingiosis in axillary lymph nodes: a possible pitfall in the staging of patients with breast carcinoma.
abstract: The occurrence of benign epithelial inclusions in lymph nodes is well documented and can sometimes mimic metastatic carcinoma. Benign müllerian inclusions, such as endometriosis and endosalpingiosis, are common in pelvic and para-aortic lymph nodes, but their presence in supradiaphragmatic lymph nodes is a rare event. We report our experience with 3 patients found to have endosalpingiosis in axillary sentinel lymph nodes obtained for staging of breast carcinoma. All patients were postmenopausal women, with age ranging between 65 and 75 years. Endosalpingiosis involved a single lymph node in 1 patient, and 2 nodes in each of the other 2; it was present in the lymph node capsule in all the 3 cases, with few glands scattered within the lymph node parenchyma in 2 of the patients. The glands contained ciliated and intercalated peg cells, had no periglandular endometrial-type stroma, and showed no atypia or mitotic activity. The epithelium demonstrated positive nuclear immunoreactivity for WT1 and PAX8, and was devoid of myoepithelium or basement membrane. Endosalpingiosis had been misinterpreted as metastatic carcinoma at another hospital in 1 of the 3 patients, with subsequent dissection of 19 additional benign axillary lymph nodes. We conclude that endosalpingiosis can involve axillary lymph nodes and closely simulate metastatic mammary carcinoma. Morphologic identification of ciliated cells and "peg" cells is most helpful to recognize this benign inclusion, and positive immunoreactivity for WT1 and/or PAX8 can be used to support the diagnosis.
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. corbena@mskcc.org
authors.forename: Adriana D
authors.initials: AD
authors.lastname: Corben
authors.forename: Tatjana
authors.initials: T
authors.lastname: Nehhozina
authors.forename: Karuna
authors.initials: K
authors.lastname: Garg
authors.forename: Christina E
authors.initials: CE
authors.lastname: Vallejo
authors.forename: Edi
authors.initials: E
authors.lastname: Brogi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology* / Q000556:secondary / Q000601:surgery; D002923:Cilia; D003951:Diagnostic Errors / Q000517:prevention & control*; D004847:Epithelial Cells / Q000737:chemistry / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000032:analysis; D011237:Predictive Value of Tests; D021701:Sentinel Lymph Node Biopsy; D019564:Unnecessary Procedures; D025721:WT1 Proteins / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors; D025721:WT1 Proteins