Secretory carcinoma of minor salivary glands of buccal mucosa: A case report and review of the literature.

INTRODUCTION AND IMPORTANCE: Secretory carcinoma (SC) is an uncommon salivary gland neoplasm of the oral cavity that microscopically may mimic acinic cell carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Secretory carcinoma (SC) of the salivary gland has been recently added in fourth edition of the head and neck world health organization. Most of these tumors are located on the parotid gland with very few cases reported in the minor salivary glands of the buccal mucosa. This work has been reported in line with the SCARE criteria. PRESENTATION OF CASE: A 42 years old hypertensive male, shop keeper by occupation, with no prior addiction history, no dental extraction or trauma, presented with complaint of nodular lesion on left buccal mucosa for five years. On Clinical examination, adequate mouth opening, dentulous patient with 2.4 × 2 cm well circumscribed, nodular, non-tender, benign looking lesion was observed on left buccal mucosa near upper alveolus. Overlying mucosa appeared normal with no clinically palpable cervical lymphadenopathy. Histopathology revealed salivary gland neoplasm favoring secretory carcinoma. MRI scan showed lobulated enhancing nodular lesion arising from left buccal mucosa of size 2.3 ∗ 1.3 ∗ 1.7 cm, close to left superior alveolus without involving any cortical areas of marrow infiltration, with bilateral symmetrical level IIa reactive cervical nodes. Wide local excision and ipsilateral selective neck dissection [level 1, 2, 3] was done. Post-operative period was smooth with no complain of paresthesia observed. The final histopathology report showed secretory carcinoma. Two out of six lymph nodes from level I were positive for metastatic carcinoma with no extra nodal extension. Final stage of the tumor was pT1N2bMx. Patient underwent post-operative adjuvant radiotherapy for period of 6 weeks, received total 30 fractions and total dose of 6000 centigray. CLINICAL DISCUSSION: SC behaved clinically an indolent being painless and having long duration of symptoms with normal overlying mucosa. But histopathologically there was cervical node metastasis. That changed final staging and added adjuvant treatment for this patient. The discrepancy in clinical and pathological diagnosis might be due to the indolent clinical behavior of SC arising in the minor salivary gland of buccal mucosa. In the present case, the absence of zymogen granules and presence of microcytic pattern with eosinophilic cytoplasm and eosinophilic secretory material were suggestive of SC. CONCLUSION: This case report represents a rare case of SC of minor salivary glands of buccal mucosa, which was indolent as per clinical presentation but on final histopathological report it had cervical nodal metastasis that changed the final stage of the disease, for which adjuvant radiotherapy was needed. Although Secretory carcinomas are generally considered having a favorable prognosis and are regarded as low- grade carcinomas with limited number of recurrence and cervical nodal metastasis, but sometimes they do metastasize to cervical nodes for which accurate and timely intervention in the form of neck dissection may be performed to establish final staging and start additional treatment modality if required for better outcome of the disease.