Primary neuroendocrine tumor of the orbit progressing to neoplastic meningitis.

A 60-year-old man presented with multiple cranial neuropathies and an identifiable left orbital lesion along the course of the supraorbital nerve. The pathologic features of the excised orbital lesion were consistent with a poorly differentiated primary neuroendocrine carcinoma. Four years after his diagnosis, the patient succumbed to neoplastic meningitis. No other primary tumor site was identified or clinically apparent during his illness.