Mammary Analogue Secretory Carcinoma of the Parotid Gland: A Rare and Unique Entity

Rosenstein Kenneth

doi:10.15406/joentr.2016.05.00140

Abstract

Mammary analogue secretory carcinoma MASC of the salivary gland is a recently described rare and unique diagnostic entity This unusual lesion corresponds histopathologically and cytogenetically to secretory carcinoma of the breast MASC of the salivary gland displays overlapping features of both mammary secretory carcinoma and acinic cell carcinoma AciCC This tumor is characterized by the chromosomal translocation p q which results in the fusion gene ETV NTRK We report a rare case of MASC presenting as a left parotid mass in a year old male which was confirmed by ETV gene rearrangement studies by Fluorescence in situ hybridization FISH MASC while rare should be considered in the differential diagnosis of salivary gland lesions

Highlights

Mammary analogue secretory carcinoma (MASC) was first described by Skálová et al.,[1] in 2010 as a unique entity of the salivary glands
Diagnosis of MASC is confirmed with the detection of chromosomal translocation (12;15) (p13;q25) leading to the fusion gene ETV6-NTRK3.4,6‒8 As a result of this translocation, the tyrosine kinase is constitutively active
An analysis from a cohort consisting of patients with mixed salivary gland neoplasms showed that post-operative radiation therapy (PORT) was most effective in controlling loco-regional recurrence in patients with incomplete resection or advanced T stage.[8,13]

Summary

Introduction

Mammary analogue secretory carcinoma (MASC) was first described by Skálová et al.,[1] in 2010 as a unique entity of the salivary glands. Low-grade salivary gland malignancies, such as MASC, are usually managed with post-operative radiation therapy (PORT) for the following indications: positive margins, perineural invasion, or the patient has a T3 or T4 tumor.[8,13] An analysis from a cohort consisting of patients with mixed salivary gland neoplasms showed that PORT was most effective in controlling loco-regional recurrence in patients with incomplete resection or advanced T stage.[8,13] A PORT dose of at least 60Gy for the aforementioned indications should be used.[13]. The differential diagnosis includes acinic cell carcinoma, mucoepidermoid carcinoma, adenocarcinoma, not otherwise specified (ADC-NOS), low-grade cribriform cystadenocarcinoma of the salivary gland.[5,8] As evidenced in the literature, the clinical behavior of this neoplasm varies significantly, from a slow-growing mass, metastatic disease at presentation, to death.[8] the clinician should be prudent in establishing an early diagnosis and proceeding with surgery and/or radiation in an expeditious manner

Conclusion

Findings

Discussion