Sclerosing Mucoepidermoid Carcinoma of the Submandibular Gland Presenting as Chronic Sialadenitis: A Case Report and Review of Literature

Detection of CSF1 gene derangement in 'sclerosing mucoepidermoid carcinoma with eosinophilia' of the parotid gland masquerading as Langerhans cell histiocytosis

Key Clinical Message

When faced with a slowly enlarging firm mass in the parotid gland accompanied by a histological picture of unusual sclerosis with abundant Langerhans cells and eosinophilic infiltrates, sclerosing mucoepidermoid carcinoma with eosinophilia should be considered as one of the differential diagnoses. Further studies are warranted for accurate diagnosis and appropriate treatment.

Abstract

Sclerosing mucoepidermoid carcinoma of the salivary gland with eosinophilia is a rare tumor mostly negative for the MAML2 rearrangement commonly seen in salivary mucoepidermoid carcinoma. It was not listed as an entity in the 2022 WHO Classification of Head and Neck Tumors. We presented one case initially diagnosed as Langerhans cell histiocytosis and recurred as a frankly invasive carcinoma. Molecular studies showed CSF1 gene derangement and provided new understanding concerning the Langerhans cell and eosinophilic reaction. Further molecular studies on this entity would throw light on its oncogenesis and refine its nomenclature.

Sclerosing variant of mucoepidermoid carcinoma: a diagnostic challenge

The sclerosing variant of mucoepidermoid salivary gland carcinoma is extremely rare. It is nearly impossible to diagnose this condition preoperatively. We present a case of a 23-year-old woman with a 1-year history of left parotid enlargement with inconclusive fine-needle aspiration cytology results. MRI showed an irregular parotid mass, and subsequent partial parotidectomy confirmed the diagnosis. We discuss the diagnostic pitfalls of this condition and provide a review of the literature surrounding its pathogenesis and management.