Neurological symptoms of leptomeningeal carcinomatosis as the primary manifestation of an adenocarcinoma of the nasal cavity and sinus: a case report and literature review. Carcinomas of the nose and paranasal sinuses are rare solid head and neck tumours. With an incidence of 1-1.5 / 100,000 per year, they account for only 3% of all malignancies in the head and neck region. Sinonasal carcinomas are often adenocarcinomas. Hardwood dust is one possible triggering agent, although the latency period may extend to decades. Central nervous system complications arising from solid tumours of the head can be explained in terms of the close anatomical relationship between the two areas. However, leptomeningeal spread is rare. To our knowledge, this is the first report demonstrating cranial nerve deficits due to a leptomeningeal carcinomatosis as the primary manifestation of an adenocarcinoma of the paranasal sinus and the nasal cavity.