[Secretory carcinoma of salivary gland: a clinicopathological and prognostic analysis of twelve cases].

Objective

To study the clinical manifestations, pathological features, molecular features, differential diagnosis and prognosis of secretory carcinoma of salivary gland (SCSG).

Methods

Twelve cases of SCSG diagnosed in the Department of Pathology, the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2019 were collected and analyzed in terms of histological morphology, immunohistochemistry (Envision method) and molecular detection.

Results

Among the 12 patients, there were 6 males and 6 females, aged 12-67 years old, with a median age of 41.5 years. The lesions in 11 patients were located in the parotid gland. The maximum diameter of the tumors ranged from 0.8 to 5.5 cm. Clinically, slow-growing painless or tender mass was the first symptom, and all patients underwent surgical resection, among which 5 patients received postoperative radiotherapy and chemotherapy, and 1 patient developed local recurrence. Histopathologically, the tumor is characterized by microcystic, solid or tubular structures with unique intravitary homogeneous secretions. Immunohistochemistry showed diffuse expression of CK7, mammaglobin, GATA-3 and S-100 in all cases, and pan-Trk in 10 of the 12 cases. Sox-10 was expressed focally in 9 cases, and Ki-67 index was 5%-20%. In molecular detection, 11 cases had ETV6 gene break/fusion.

Conclusions

SCSG is a relatively rare low-grade malignant salivary gland tumor, with typical histological morphology and immunophenotype, Pan-Trk immunohistochemistry may be related to NTRK fusion, ETV6-NTRK3 gene rearrangement is not only of diagnostic significance, but also Trk-targeted therapy is expected to play a greater role in clinical treatment.