Extramedullary tumors and leukemia: a diagnostic pitfall for the neurologist.

Objective: To describe neurologic presentations and radiologic findings of extramedullary myeloid tumor (EMT).

Methods: This is a retrospective case series of patients with neurologic presentations of EMT from January 1, 1981, until May 30, 2011. Clinical data abstracted included demographics, presentation, bone marrow involvement, history of hematologic malignancy, complete blood count at presentation, EMT location, imaging findings, treatments, and outcomes.

Results: Of 21 patients, EMT was the initial presentation of underlying hematologic disorder in 12 (57%). Six patients (29%) presented with primary EMT (no bone marrow involvement at presentation). The most common location was the thoracic spine (n = 9), usually manifesting as an epidural mass with vertebral body involvement. The initial diagnosis was incorrect in most (n = 17 [81%]). Treatments included radiation (n = 17 [ 81%]), chemotherapy (n = 14 [67%]), and surgery (n = 6 [29%]). Fifteen patients (71%) died. Estimated Kaplan-Meier median survival from diagnosis for 20 patients with adequate follow-up was 8 months. Of the 6 patients with primary EMT (no known systemic leukemia at diagnosis), 5 died at a median of 24 months (range 8-36 months) and 1 is still alive at 1 year. Of the 6 patients whose leukemia was diagnosed upon presenting with EMT, 3 are still alive.

Conclusions: EMT affecting the nervous system can present in patients without a known hematologic disorder and is often not recognized. Thoracic paraspinal masses are the most common presentation. The prognosis for patients with neurologic presentation of EMT is generally poor, but longer survival is possible in patients presenting with isolated EMT or leukemia first diagnosed at the time of EMT presentation.