Case of metastatic small cell carcinoma of the oropharynx successfully treated with image-guided volumetric modulated arc therapy (IG-VMAT): pushing the limits of technology to match treatment intent.

Extrapulmonary small cell carcinomas (EPSCC) are a rare subtype of neuroendocrine tumours which have been documented to arise from a multitude of sites and treatment outcomes are disappointing. The most common site involved in the head and neck region is the larynx and the oropharynx as a primary site has been infrequently reported. The patient presented with bilateral neck swelling and an ulcerated lesion was noted in the base of tongue (BOT). A biopsy revealed small cell carcinoma (SCC) and was confirmed with immunohistochemistry. The final diagnosis after workup was SCC of BOT stage IVc. He received induction chemotherapy to which the tumour responded partially, followed by curative intent chemoradiotherapy and adjuvant chemotherapy. The patient achieved a radiological complete response to treatment and almost all treatment-induced toxicities resolved. An aggressive approach to managing EPSCC is possible with modern radiotherapy techniques, with tolerable treatment-induced toxicities.