Unmasking the rarity of mammary analogue secretory carcinoma of the minor salivary gland - A case report

Mammary analogue secretory carcinoma (MASC) of the salivary gland was first described by Skálová et al. in 2010. It is often associated with a translocation, t(12;15)(p13;q25), which results in the fusion gene ETV6-NTRK3. Major salivary glands, primarily the parotid gland, are involved in 70 % of cases of MASC, while small salivary glands are involved in less than 25 % of cases. This report aims to consolidate in unveiling, diagnosing, and managing the rarity of MASC in the minor salivary gland and its existing knowledge and encourage new research on this increasingly important salivary gland malignancy. A 27-year-old female reported with a complaint of swelling on the right cheek region of face since 10 weeks. On bimanual palpation, a soft lobulated mass was appreciated beneath the healthy mucosal layer. The radiographic image (orthopantomogram) showed no obvious calcified mass. An excisional biopsy was planned and performed under local anesthesia. Microscopic and immunohistochemistry confirmed the tumor to be a MASC of minor salivary gland. Due to their infrequency and multiplicity of histopathology, MASC presents difficulty in diagnosis. A key to determining diagnostic criteria for MASC is to study cellular morphology, cytoplasmic filament expression, and ultrastructural features of the tumor and apply this information to defining MASC. MASC is an important molecularly defined entity of the salivary gland with low-grade malignant potential. Correct diagnosis is essential for appropriate treatment and will help to provide better information about this potentially low-grade malignant salivary gland neoplasm. •Mammary analogue secretory carcinoma of minor salivary gland•Electron microscopy and Immunohistochemistry•Low-grade carcinoma of salivary glands•Secretory carcinoma of breast