title: Lymphadenoma: case report of a rare salivary gland tumor in childhood.
abstract: Lymphadenoma of the salivary gland is a rare benign tumor with only 11 reported cases in the English language literature, most of which have occurred in adults. We report a case of a lymphadenoma occurring in the parotid gland of a 15-year-old girl. The tumor was composed of variably sized cystic cavities within abundant reactive lymphoid tissue. The cystic spaces were filled with eosinophilic secretions with occasional histiocytes. Many of these features were also apparent on cytologic preparations. The cysts were lined by epithelium lacking atypia and showed luminal and abluminal differentiation both by immunohistochemistry and by electron microscopy. Tumor cells were not cycling as determined by MIB1 immunostaining, and the tumor karyotype was normal. This is only the second case to be reported in the pediatric age group. Ultrastructural features and karyotype analysis are reported for the first time. Although this tumor is rarely encountered by pediatric pathologists, awareness of its existence is important to distinguish it from possible malignant mimics, such as lymphoepithelial carcinoma and metastatic mucoepidermoid carcinoma in a lymph node.
authors.affiliation: Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Kenneth T E
authors.initials: KT
authors.lastname: Chang
authors.forename: Neil K
authors.initials: NK
authors.lastname: Chadha
authors.forename: Richard
authors.initials: R
authors.lastname: Leung
authors.forename: Mary
authors.initials: M
authors.lastname: Shago
authors.forename: M James
authors.initials: MJ
authors.lastname: Phillips
authors.forename: Paul S
authors.initials: PS
authors.lastname: Thorner
mesh_terms: D000235:Adenolymphoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D000293:Adolescent; D014408:Biomarkers, Tumor / Q000378:metabolism; D018277:Carcinoma, Mucoepidermoid / Q000175:diagnosis / Q000556:secondary; D022083:Cytoplasmic Structures / Q000648:ultrastructure; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008214:Lymphocytes / Q000648:ultrastructure; D010307:Parotid Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D010950:Plasma Cells / Q000648:ultrastructure; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D016896:Treatment Outcome; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C115051:TP63 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D007633:Keratins; D019009:Proto-Oncogene Proteins c-kit