title: Myoepithelioma of parotid gland presenting as infra-auricular subcutaneous mass.
abstract: Myoepithelioma is a rare but well-characterized group of tumours, among which myoepithelioma of the salivary glands is the best known. We report two patients with myoepithelioma of parotid gland presenting as infra-auricular subcutaneous mass. The lesions were clinically suspected to be epidermal cyst. The biopsies revealed that most of the tumour cells showed epithelioid features with oval or spindle eosinophilic cytoplasm. No ductal or syringomatous epithelial structures were observed. The tumour cells showed cytoplasmic immunoexpressions of vimentin, cytokeratin (AE1/AE3), S-100 protein and smooth muscle actin (SMA). In one patient, a strong calponin positivity was observed. Maguetic resonance imaging (MRI) of both patients revealed exophytic, well-defined, strongly enhancing mass in superficial lobe of parotid gland, confirming the parotid gland origin. Myoepithelioma of parotid gland can be presented as a slowly growing tumour of pre- or infra-auricular area. In dermatologic department, it can be misdiagnosed as various dermal or subcutaneous tumours.
authors.affiliation: Department of Dermatology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul 138-736, South Korea.
authors.forename: Mi-Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Soon-Yuhl
authors.initials: SY
authors.lastname: Nam
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Choi
authors.forename: Jee-Ho
authors.initials: JH
authors.lastname: Choi
authors.forename: Kee-Chan
authors.initials: KC
authors.lastname: Moon
authors.forename: Jai-Kyoung
authors.initials: JK
authors.lastname: Koh
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009208:Myoepithelioma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D010307:Parotid Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000378:metabolism; D012983:Soft Tissue Neoplasms / Q000175:diagnosis*; D040521:Subcutaneous Tissue / Q000473:pathology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D000199:Actins; D014408:Biomarkers, Tumor; D009418:S100 Proteins; D014746:Vimentin; D007633:Keratins