Cytological features of mammary analogue secretory carcinoma of salivary gland: Fine‐needle aspiration of seven cases

Abstract

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland neoplasm that is defined by ETV6‐NTRK3 gene fusion. There have been few case reports on the cytopathologic features of MASC to date. We examined the clinicopathological and cytological features of seven cases of MASC defined by RT‐PCR analysis of the ETV6‐NTRK3 fusion gene. The cases occurred in three men and four women aged between 39 and 68 years, with a mean of 51.6 years. In five of these seven cases, the tumor involved the parotid gland. Histologically, all cases displayed predominantly microcystic patterns, often a mixture of follicular and papillary‐cystic structures. All tumors were immunoreactive for mammaglobin, S‐100 protein, and vimentin. Available fine‐needle aspiration cytology smears were cellular and exhibited many loosely cohesive syncytial clusters or isolated cells. Many histiocytes, some of which contained hemosiderin pigments, and variously shaped mucinous material were evident in the background or within the epithelial clusters. The majority of cases showed small to medium‐sized follicular structures with secreted materials. Papillary clusters were occasionally found. Tumor cells exhibited small to medium‐sized round to oval nuclei, with a smooth contour and indistinct or small nucleoli, and vacuolated cytoplasm. No tumor cells had obvious intracytoplasmic zymogen granules. It appeared that clusters of small to medium‐sized follicular and papillary configurations consisting of bland tumor cells with vacuolated cytoplasm, but lack of intracytoplasmic zymogen granules, in a mucinous or hemosiderin‐laden histiocyte‐rich background, were a characteristic cytological feature highly suggestive of MASC. Diagn. Cytopathol. 2014;42:846–855. © 2014 Wiley Periodicals, Inc.

Difficulty in the Cytodiagnosis of Mammary Analogue Secretory Carcinoma: Survey of 109 Cytologists with a Case Originating from a Minor Salivary Gland

“…The reported cytological features of MASC are as follows [7,9,12,13,17,18] . (1) The nuclear shape is round to oval, with a smooth contour, and the nuclear atypia is mild to moderate with a fine or open chromatin pattern.…”

Fine-Needle Aspiration Cytology of Mammary Analog Secretory Carcinoma Masquerading as Low-Grade Mucoepidermoid Carcinoma: Case Report with a Review of the Literature

“…Staining for p63 and SMA was negative. This pattern of staining has been observed by most authors [1,3,4,5,6,7,8,9,10,11,12,13]. However, there have been reports of other salivary gland tumors expressing mammaglobin and S-100.…”

“…Mammaglobin staining was observed in 11% of the MEC and 6% of the PA cases studied by Bishop et al [4]. Higuchi et al [12] reported focal p63 expression in 2 of their 7 cases of MASC; however, localization of the stain, i.e. cytoplasmic or nuclear, was not clarified.…”

“…The age of presentation ranges from 13 to 78 years with the mean age being in the 5th decade [14]. The current cytology literature is limited to a few reported cases [1,3,4,5,6,7,8,9,10,11,12,13]. The original cytologic diagnoses of all but 1 of the 23 cases reported in the literature ranged from benign salivary epithelium to high-grade salivary gland carcinoma, the most common diagnosis being acinic cell carcinoma (AcCC) followed by ‘low grade neoplasm' and mucoepidermoid carcinoma (table 1).…”

“…The transformation has been shown to be mediated through the activation of the c-Jun/Fos1 AP1 complex [2]. Nearly 90 cases of MASC have been published in the last couple of years [1,3,4,5,6,7,8,9,10,11,12,13]. In nearly two thirds of the reported cases, MASC presents as a painless, slow-growing mass involving the parotid gland, followed by the minor oral and submandibular salivary glands, with a slight male predominance.…”