Isolated III cranial nerve palsy: a Hodgkin's lymphoma?

A 69-year-old woman developed ptosis and diplopia due to an isolated pupil-involving left oculomotor nerve palsy. General examination was unremarkable. Initial workup showed a mild increase in cerebrospinal fluid proteins. Imaging studies were remarkable for a left oculomotor nerve enhancement in brain MRI and hyperfixation along the nerve's pathway in full body single-photon emission CT. Assuming the possible diagnosis of neurosarcoidosis, the patient was started on high-dose methylprednisolone. Three months later she developed pancytopenia. A bone marrow biopsy was performed and histopathology revealed infiltration by Hodgkin's lymphoma. Adriamycin, bleomycin, vinblastine, dacarbazine protocol chemotherapy was started and full haematological remission obtained after four cycles, despite mild oculomotor nerve palsy persisted. Isolated oculomotor palsy as the first presenting manifestation of a lymphoma is rare and alternative differential diagnosis must be considered in the absence of other lymphoma manifestations. In this case as with many rare initial manifestations of common diseases watchful waiting was crucial to the correct diagnosis and treatment strategy.