Nonsebaceous lymphadenoma of salivary gland: report of a case with immunohistochemistry and review of the literature

Objective. Nonsebaceous lymphadenomas are rare, benign neoplasms. We emphasize the role of immunohistochemistry and attempt to elucidate the pathogenesis, investigating the distribution of two transcription factors, MYC and BLIMP1. Study Design. A 70-year-old man was evaluated for a 3 cm, left parotid mass. Ultrasound-guided fineneedle aspiration biopsy findings were suggestive of a diagnosis of pleomorphic adenoma. A left superficial parotidectomy was performed and based on histopathology a diagnosis of lymphadenoma, nonsebaceous type, was rendered. Results. The tumor was positive for AE1/3, CKA, Bcl2, P63, CD79a, CD3 and MYC; focal positive for CK7 and EMA; negative for CD10, Calponin, CD117 and BLIMP1. Conclusions. The rarity and its superficial resemblance to commoner salivary-gland tumors may present a diagnostic challenge for pathologists. The expression of MYC in the ductal component and the differentiation-related expression of PRDM1 in the superficial keratinizing layers, point to a role for these two transcription factors in the pathogenesis of this neoplasm.