Elusive Primary in Low Grade Mucoepidermoid Carcinoma: Dilemma of Chronology and Terminology

Salivary gland tumours constitute an uncommon and diverse group of neoplasms that vary considerably in their histology and biologic behaviour. As per Globocon 2018, salivary gland malignancy account for 0.3% of all cancer cases and 0.2% of all cancer deaths worldwide, reflecting the rarity of these neoplasms. Mucoepidermoid carcinoma (MEC) is a common malignant tumour of major and minor salivary gland, which comprises about 10% of all salivary gland neoplasms and approximately 35% of malignant salivary gland neoplasms. While three fourth of cases of MEC arise in the parotid, they account for a large proportion of salivary gland neoplasms occurring in minor salivary glands. Appending to the uncommonness, unusual presentations like MEC arising in heterotopic rests of salivary gland tissue in intraparotid or extraparotid lymph nodes, and MEC arising in lingual tonsils have been reported. Such diversity of clinical presentation may present a diagnostic challenge. In this continuum, we report a rare and unique case of low grade mucoepidermoid carcinoma of minor salivary gland, which primarily presented as cervical lymph node metastasis, three years before the primary intraoral lesion occurred.