Mammary analog secretory carcinoma parotid gland: Case report of a recently described tumor with review of literature

Abstract

Mammary analog secretory carcinoma (MASC) is a low-grade malignant tumor of salivary glands. It is so named because of its cytohistopahological, immunohistological, and cytogenetic resemblance to secretory carcinoma of the breast. Since the first description of this tumor in 2010, about 70 cases have been reported in literature. We report a case of this recently described tumor in a 21-year-old female. The radiological diagnosis of her parotid swelling was pleomorphic adenoma. The cytological evaluation was suggestive of oncocytoma. The histopathology showed a low-grade malignant neoplasm and the differential included papillary variant of acinic cell carcinoma, oncocytic variant of mucoepidermoid carcinoma, and MASC. Immunohistochemistry confirmed the diagnosis of MASC. We have included a brief review of literature.

A rare case of mammary analogue secretory carcinoma of the parotid gland; A diagnostic and management challenge

“…An average age of 45.7 years has been reported in existing literature [1,3,9]. MASCs are generally low-grade tumors with minimal recurrence rate and rare metastasis, but high-grade transformation and aggressive clinical characteristics have been witnessed and recorded on rare occasions, which manifests as recurrence, regional lymph node metastases, or even diseaserelated fatalities [1,3,4,6,8]. On gross appearance, MASCs may get misdiagnosed as a cystic mass, lymphangioma or a benign nodule.…”

“…They were first described by Skalova et al in 2010 after reviewing 16 salivary gland tumor cases, previously labelled as either acinic cell carcinoma or adenocarcinomanot otherwise specified, and finding features similar to secretory carcinoma of the breast [2]. Characterized by the t(12;15) (q13;q25) translocation, MASCs are generally solitary and well circumscribed lesions and can be found in all age groups, including children and young adults, and typically involve the parotid region, but have been known to affect other locations in the head and neck region as well [1,3,4]. Due to its propensity to display histologic features, such as central nuclei in tumor cells or a pink granulated or vacuolated cytoplasm, typically found in relatively common salivary gland malignancies, MASCs were commonly misdiagnosed as adenocarcinomas -not otherwise specified and acinic cell carcinomas of the salivary glands [5].…”

“…Markers such as DOG1, PAS-D, S100 and mammaglobin are especially useful when used in conjunction to accurately identify MASC [7]. However, immunohistochemistry is utilized as a supportive tool only and confirmation of the diagnosis is made only by demonstrating the characteristic t(12;15)(q13;q25) translocation, which results in the fusion gene ETV6-NTRK3, with the ETV6 gene from chromosome 12 and the NTRK3 gene from chromosome 15 [1,4]. In total, less than 100 cases of MASCs have been reported in existing literature and management guidelines for the tumor are not yet clearly defined.…”

Fine-needle aspiration cytology of mammary analog secretory carcinoma of the parotid gland: A diagnostic conundrum

“…Less common subsites include submandibular glands and other oral cavity subsites such as the soft palate, buccal mucosa, base of tongue, and lips. [2]…”

“…The features that aid in the diagnosis of AciCC are the presence of basophilic cytoplasmic (zymogen) granules which are PAS diastase-resistant and the absence of mucin production. [2] Other helpful features of AciCC are nuclei with macronucleoli and abundant arborizing vessels. However, granular AciCC can be really challenging, which can be resolved using immunohistochemical studies.…”