Diagnosis and treatment of secretory carcinoma arising from the oral minor salivary gland: Two case reports.

INTRODUCTION: Secretory carcinoma (SC) is a malignancy of the salivary glands, which is similar to SC of the breast regarding its association with neurotrophic tyrosine receptor kinase fusion-positive gene. SC is a recently described salivary gland tumor, and there are a few reports describing oral minor salivary gland-derived SC. We reported two cases of SC in the oral cavity and reviewed the literature.

PATIENT CONCERNS: The patients included a 65-year-old Japanese woman who presented with a mass of the upper lip and an 84-year-old Japanese man who presented with a mass on the buccal mucosa.

DIAGNOSIS: Diagnosis was based on histomorphological and immunohistochemical findings and identification of a specific translocation of the ETS variant 6-neurotrophic receptor tyrosine kinase 3 gene fusion. Case 1 was finally diagnosed using reverse transcription-polymerase chain reaction with formalin-fixed paraffin-embedded tissue samples, while case 2 was diagnosed using fluorescence in situ hybridization analysis.

INTERVENTIONS AND OUTCOMES: In case 1, excisional biopsy was done and there was no recurrence observed in five-year follow-up. In case 2, tumor resection was done and there was no recurrence observed in two-year follow-up.

CONCLUSION: It is highly likely for many cases of SC to be initially diagnosed as acinic cell carcinoma (AciCC) owing to their similar histological findings. The treatment strategy for minor salivary gland-originated SC is similar to that of AciCC; however, SC is often highly malignant and involves a high risk of cervical lymph node metastasis. Thus, establishing an accurate diagnosis together with pathologists and confirming the presence of the ETS variant 6-neurotrophic receptor tyrosine kinase 3 fusion gene using genetic analysis is important.