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.

[Secretory carcinoma of the salivary gland (mammary analogue secretory carcinoma) in children]

Secretory carcinoma of the salivary gland is a tumor that was first described less than 10 years ago and that mainly occurs in the parotid salivary gland in the elderly. Analyzing the literature over 8 years since the first description of the tumor identifies the main clinical, morphological, and genetic signs of the diagnosis of secretory carcinoma with a focus on the pediatric population. Four new cases of secretory carcinoma of the salivary glands, which have been diagnosed in children of the youngest age encountered in the literature, are also described.

Outcomes of treatment of mammary analogue secretory carcinoma of the parotid gland

Mammary analogue secretory carcinoma (MASC) of the salivary gland is a newly-described, rare, malignant tumour. Few patients present with MASC of the parotid gland, so the exact characteristics, outcomes of treatment, and prognosis are unknown. The aim of this study was to analyse the clinical features and outcomes of treatment of MASC of the parotid gland in patients being treated at a single hospital. Five patients with histopathologically-confirmed MASC of the parotid gland between January 2015 and August 2018 were retrospectively enrolled. In all cases preoperative fine-needle aspiration cytology had failed to provide an accurate diagnosis. All patients underwent a macroscopically complete oncological resection. Two patients had postoperative radiotherapy (RT). On immunohistochemical examination all tumours stained for S-100 and mammaglobin but not for DOG1. There were no regional recurrences or distant metastases in any of the patients at their last follow-up. We obtained good results for patients with MASC of the parotid gland with surgical treatment and postoperative RT.