SECRETORY CARCINOMA OF THE PAROTID GLAND IN A 9-YEAR-OLD FEMALE PATIENT: A CASE REPORT AND REVIEW OF THE LITERATURE

Introduction Formerly known as mammary analogue carcinoma (MASC), secretory carcinoma of the salivary glands (SCSG) is a low-grade malignancy harboring the ETV6-NTRK3 translocation. SCSG shares morphological and genetic features with secretory carcinoma of the breast. It shows a characteristic protean histological phenotype reminiscent of acinic cell carcinoma, mucoepidermoid carcinoma, and adenocarcinoma, NOS. We report a case of SCSG in a pediatric patient showing a pure zymogen-poor acinic cell carcinoma morphology. Clinical presentation A 9-year-old female patient presented to the ENT clinic with 8 months history of left facial swelling. Imaging studies showed a 2.7 cm lesion of the left parotid gland with no lymphadenopathy. Left lateral lobe parotidectomy with facial nerve dissection and preservation was performed. Gross examination of the tumor revealed a tan, hemorrhagic ill-defined mass, measuring 2.5 × 2.4 × 2 cm. Microscopic examination showed lobulated growth pattern consisting of papillary architecture and microcystic spaces. Lobules of tumor cells were identified in the intraparotid lymph node. The tumor was negative for DOG-1 and strongly positive for Mammaglobin, S-100, GATA-3, CK 7, and Pan cytokeratin. The ETV6 gene translocation was subsequently detected by FISH. Literature review A total of 17 cases of pediatric SCSGs (age range: 8-18 years) have been reported in the literature. The parotid gland (88%) is the most common location. The mainstay of treatment is surgical resection. Based on the limited number of documented cases, SCSG appears to show an indolent biological behavior rarely occurring in pediatric patients. Conclusion Because of the spectrum of histological patterns of SCSG, immunohistochemical markers and genetic documentation of the ETV6-NTRK3 gene fusion are essential to correctly diagnose this tumor.