Multimodal Management of Patients with Sinonasal Neuroendocrine Carcinoma with Infiltration of the Skull Base and Intradural Frontobasal Brain Invasion

Background: Neuroendocrine carcinomas (NEC) are rare malignant tumors. They can be classified as well-differentiated, moderately differentiated or poorly differentiated. In the head and neck area, NEC commonly occurs in the larynx. As they rarely appear in the sinonasal tract with skull base and frontal lobe invasion, currently there is no standardized treatment of this entity. Moreover treatment of NEC with skull base and intraparenchymal brain invasion poses several surgical challenges. We present the multimodal management of NEC in a recent small patient series.

Material and Methods: From 2014 to 2015, three patients with NEC and infiltration of the skull base and intradural frontobasal brain invasion have been diagnosed and treated at our hospital. Treatment strategy was discussed in interdisciplinary tumor board.

Results: All patients underwent endonasal endoscopic surgery (EES) with extended surgical approaches to achieve an adequate tumor exposure. In one of them a neoadjuvant chemotherapy consisting of cisplatin and etoposide was performed. Complete resection was feasible in all patients without surgical complications. One patient is currently being treated with adjuvant radiochemotherapy with carboplatin and 5-FU, two patients received no adjuvant treatment. Of the three patients, one presented with a cT1, one with a cT3 and one with cT4 tumor stage. Histologically, we found one G1, one G2, and one G3–4 neuroendocrine carcinoma.

Conclusion: Multimodal and interdisciplinary management of NEC is effective and to our opinion a prerequisite for a successful treatment. Extended endonasal surgical approaches facilitate surgical resection with thorough reconstruction of the frontal base and low perioperative complications.