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Revista Española de Cirugía Oral y Maxilofacial

versão On-line ISSN 2173-9161versão impressa ISSN 1130-0558

Rev Esp Cirug Oral y Maxilofac vol.42 no.1 Madrid Jan./Mar. 2020  Epub 04-Maio-2020 


A rare case of a recently described entity: mammary analogue secretory carcinoma (MASC) of the parotid gland

Un caso raro de una entidad descrita recientemente: carcinoma secretorio análogo mamario (CSAM) de la glándula parótida

Frederico Martinsa  *  , Tiago Netoa  , Ana Marquesb  , Rui Balhaua 

aMaxillo-Facial Surgery Department, Centro Hospitalar e Universitário de São João. Porto, Portugal.

bPathology Department, Centro Hospitalar e Universitário de São João. Porto, Portugal.


MASC is a salivary gland tumour which shares histological, immunologic and genetic characteristics with mammary secretory carcinoma including an ETV6 translocation and immunocytochemical positivity for S-100 protein, CK7, and mammaglobin as well as negativity for DOG1. This is a rare tumour with uncommon characteristics when compared to other salivary gland tumours. The case reported here is of a 28-year-old female patient who presented in the ER due to a palpable mass in the left parotid region. She underwent a superficial parotidectomy with using a mini-lifting approach, with tumour resection, followed by radiotherapy. The identified tumour shared most of the clinical characteristics with other cases of MASC described in the literature.

Keywords: MASC; mammary analogue secretory carcinoma; secretory carcinoma; salivary glands


CSAM es un tumor de glándula salival que comparte características histológicas, inmunológicas y genéticas con el carcinoma secretor mamario, que incluye una translocación ETV6 y positividad inmunocitoquímica para la proteína S-100, CK7 y mamaglobina, así como negatividad para DOG1. Este es un tumor raro con características poco comunes en comparación con otros tumores de glándulas salivales. El caso referido aquí es el de una paciente de 28 años de edad que se presentó en la sala de emergencias debido a una masa palpable en la región parotídea izquierda. Se sometió a una parotidectomía superficial con un abordaje de mini-lifting, con resección tumoral, seguida de radioterapia. El tumor identificado compartía la mayoría de las características clínicas con otros casos de CSAM descritos en la literatura.

Palabras clave: CSAM; carcinoma secretorio análogo mamario; carcinoma secretorio; glándulas salivales


MASC is a low-grade malignant salivary gland cancer, first described by Alena Skálová in 20101, with various similarities to the secretory carcinoma of the breast including histology, immunohistochemistry and a genetic translocation2.

Epidemiologically, it is usually encountered in adults with a mean age of 46 years-old3 and a slight male predominance3,4. There have been 11 cases described in the paediatric population5.

There are three main differential diagnosis: AciCC which is positive for DOG1, does not have the ETV6-NTRK3 fusion gene and has basophilic granularity in the cytoplasm as an hallmark2,3; mucoepidermoid carcinoma which is positive for p63 and is usually negative for S100 and mammaglobin in addition to having, in most cases, a t(11;19) translocation3 and, low-grade cribriform cystadenocarcinoma which has epithelial structures surrounded by an intact layer of p63 positive myoepithelial cells2.

MASC is usually found in the parotid gland3,4 followed by the oral cavity and submandibular gland3. The most common presentation is of a slowly growing painless nodule2. In most cases it has good prognosis and an indolent course4. High grade transformation followed by an accelerated clinical course with poor prognosis has been described3,4.


Our case is of a 28-year-old women with no relevant past medical history who presented in the ER with a week old, hard, 5x5mm, adherent and tender nodule in the left parotid region. There was no history of trauma or other symptoms.

Pre-operatory work-up included: blood analysis which showed no relevant alteration; ultrasound which showed a 8x5mm, lobulated, hypoechoic nodule with liquid/cystic content; cytology which described a low grade epithelial / myoepithelial tumour and an MRI describing a bilobulated, 8x5mm, nodule with well-defined borders and a thin wall in the left superficial parotid gland with anterior extension to the masseter muscle.

Thus, we performed a superficial left parotidectomy using a retro-tragal mini-lifting approach. There were no complications during surgery and the facial nerve was preserved.

Follow-up included a pathology exam in which the tumour was described as a brownish-yellow well delimitated nodule with a larger diameter of 0.4 cm. Histology (Figure 1) showed an encapsulated neoplasia (A) with a cribriform/microcystic pattern. Neoplastic cells had irregular nuclei, eosinophilic cytoplasm and secretion product in the gland-like spaces (B). Immunohistochemically (Figure 2) the neoplastic cells were positive for CK7 (C), mammaglobin (D), GATA-3 (E) and S100 protein (F) and negative for DOG-1 (G) and P63 (H).

Adjunctive radiotherapy with a total dose of 60Gy was also performed and, to date, the patient remains asymptomatic with no signs of recurrence.

Figure 1. Histology showed an encapsulated neoplasia (A) with a cribriform/microcystic pattern. Neoplastic cells had irregular nuclei, eosinophilic cytoplasm and secretion product in the gland-like spaces (B) 

Figure 2. Immunohistochemically the neoplastic cells were positive for CK7 (C), mammaglobin (D), GATA-3 (E) and S100 protein (F) and negative for DOG-1 (G) and P63 (H) 


MASC is, generally, a solitary2, firm/rubbery mass with a white to grey cut surface3. Fluid-filled cystic spaces may be seen3. Perineural invasion and extension to extra-glandular tissues occurs often but lymphovascular invasion and necrosis are uncommon2,3. Histologically it is a well-defined multilobulated tumor divided into segments by fibrous septa4. Neoplastic cells have uniform and round nuclei3 with centrally located small nucleoli and eosinophilic vacuolated cytoplasm, and can be arranged in microcystic, cribriform, tubular, papillary, follicular or solid nests pattern3,4. Microscopic foci of invasion can be present although atypia is generally mild and mitotic activity is scarse3,4.

Immunohistochemically, it is positive for a wide-spectrum of cytokeratins (AE1-AE3, CAM5.2, CK7, CK8, CK18, CK19), S100 protein, mammaglobin and, in most cases, GCDFP-15, SOX10, GATA-3 and vimentin3,4. Basal cell / myoepithelial markers such as p63, calponin, CK14, SMA, and CK5/6 are virtually always negative. Most cases are negative for DOG-13

Genetically, a t(12;15)(p13;q25) translocation resulting in the ETV6-NTRK3 fusion gene is present4. ETV6 is a transcriptional regulator and NTRK3 is a membrane receptor kinase3. The fusion gene results in a ligand independent activation of the kinase thus promoting cell proliferation and survival2,3. This fusion gene has not been described in other salivary gland tumours3 .

Imagiologic descriptions are lacking in the literature. On MRI the tumour shows hyperintensity relative to muscle in T1 and hypointensity relative to the parotid gland in T22.

The treatment of choice in MASC is complete surgical resection (standard care for low grade salivary carcinomas) 2,3. Locoregional radiation is sometimes considered, mostly in cases with positive margins or perineural invasion3, although the impact on prognosis is not established2. Systemic chemotherapy can be implemented if distant metastases are present3. Response to tyrosine kinase inhibitors has been described in other tumours with the ETV6 translocation but not in MASC3.


1. Skálová A, Vanecek T, Sima R, Laco J, Weinreb I, Perez-Ordonez B, et al. Mammary analogue secretory carcinoma of salivary glands, containing the ETV6-NTRK3 fusion gene: A hitherto undescribed salivary gland tumor entity. Am J Surg Pathol. 2010;34(5):599-608. DOI: 10.1097/PAS.0b013e3181d9efcc. [ Links ]

2. Sethi R, Kozin E, Remenschneider A, Meier J, VanderLaan P, Faquin W, et al. Mammary analogue secretory carcinoma: Update on a new diagnosis of salivary gland malignancy. Laryngoscope. 2014;124(1):188-95. DOI: 10.1002/lary.24254. [ Links ]

3. Skálová A, Gnepp DR, Lewis JS Jr, Hunt JL, Bishop JA, Hellquist H, et al. Newly Described Entities in Salivary Gland Pathology. Am J Surg Pathol. 2017;41(8):e33-e47. DOI: 10.1097/PAS.0000000000000883. [ Links ]

4. Damjanov I, Skenderi F, Vranic S. Mammary Analogue Secretory Carcinoma (MASC) of the salivary gland: A new tumor entity. Bosn J Basic Med Sci. 2016;16(3):237-8. DOI: 10.17305/bjbms.2016.1321. [ Links ]

5. Ngouajio AL, Drejet SM, Phillips DR, Summerlin DJ, Dahl JP. A systematic review including an additional pediatric case report: Pediatric cases of mammary analogue secretory carcinoma. Int J Pediatr Otorhinolaryngol. 2017;100:187-93. DOI: 10.1016/j.ijporl.2017.07.004. [ Links ]

Received: April 29, 2019; Accepted: September 11, 2019

* Autor para correspondencia: Correo electrónico: Fredecirco Martins:

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