MiNEN of base of tongue - first case report in literature.

Introduction: Mixed neuroendocrine and non-neuroendocrine neoplasms (MiNENs) refer to a heterogenous group of rare neoplasms which is usually composed of a neuroendocrine population which is either well differentiated and more frequently poorly differentiated along with a non-neuroendocrine component, each of the above accounting for at least 30% of the tumour population. It is most commonly seen in the gastro-entero-pancreatic tract. MiNENs have an aggressive behaviour due to its high grade neuroendocrine component and have poor prognosis. This is the first case reported in literature of a MiNEN in the oropharynx.

Case report: 69 year old male patient with no co morbidities presented to the outpatient department with complains of odynophagia for 1 month. He had history of neoadjuvant chemotherapy followed by transoral robotic surgery (TORS) with right selective neck dissection (SND) done in 2019 for carcinoma base of tongue. On flexible laryngoscopy, an ulcerative lesion was noted over the left base of tongue. Although PET scan done showed no significant abnormalities. Biopsy from the lesion showed features of poorly differentiated carcinoma along with morphological features of poorly differentiated neuroendocrine carcinoma (small cell carcinoma). He was planned for upfront surgery (TORS with left SND). Post operatively recovery was uneventful and patient was on ryles tube feed for 12 days. Final histopathology report showed features of mixed neuroendocrine non neuroendocrine neoplasm. He has been on follow up for 1 year with no features of recurrence.

Conclusion: MiNEN is an aggressive tumour which has poor prognosis and is most commonly located in the gastrointestinal tract. This is the first case reported in oropharynx who has been successfully treated and has been on follow up.