Myeloblastic meningeal neoplasm: an unusual natural history.

Myeloid sarcoma is a very rare extramedullary malignant tumour, most often associated with acute myeloid leukaemia. We report the case of a man in his early 20s who presented with chronic headache, raised intracranial pressure and progressive vision loss of 2 years duration with no systemic manifestations. He had a history of myeloid sarcoma of the left thigh 15 years ago, treated with external beam radiotherapy and in complete remission for more than 13 years. However, the progressive blindness remained unexplained for 2 years, and he was eventually diagnosed with isolated meningeal relapse without marrow or systemic involvement. Imaging revealed subarachnoid haemorrhage, diffuse leptomeningeal enhancement and involvement of lower dorsal cord and conus, and cerebrospinal fluid cytology showed myeloid blasts. He was managed with intrathecal chemotherapy and craniospinal irradiation, after which he had mild improvement in vision.