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The Clinco-pathological, immunohistochemical and molecular findings of four cases of Mammary Analogue
Secretory Carcinoma (MASC) of salivary glands found in Mexico are described.
The cases were extracted from 253 salivary gland tumors from a single institution in Mexico City. The 85 candidates for initial selection were: low grade mucoepidermoid carcinoma (MEC) (N=70 ), acinic cell cancinoma
(AciCC) (N=14), papillary cystadenocarcinoma (N=1), and adenocarcinoma NOS (N=0). Tumors with some histological features consistent with MASC (N= 17, 6.7%) were studied by immunohistochemistry for mammaglobin,
STAT5, and S-100 protein and four cases were positive (1.5%), thus the diagnosis of MASC was established, and
these were submitted for molecular studies for
ETV6-NTRK3
. Fusion gene was demonstrated in three cases, two
had been erroneously diagnosed as poorly granulated AciCC, and one as low grade MEC with microcystic pattern. Female gender predominated (3:1); one occurred in the parotid, two in minor salivary glands and one in the
submaxillary gland; infiltrating borders, atypical mitosis and lymph node metastases were seen in the parotideal
tumor. Two patients with major salivary gland tumors are alive and well at 10 and 20 months respectively, the two
patients with minor salivary gland tumors are lost.
It can be concluded that is important to think in MASC in poorly granulated AciCC and low grade MEC with
microcystic pattern. Immunohistochemisty studies confirm the diagnosis, preferentially supported by molecular
studies. MASC may follow aggressive behavior or transform into a high grade neoplasm.
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