Acute promyelocytic leukemia presenting as an extradural mass.

Acute promyelocytic leukemia is potentially a highly curable type of leukemia that usually presents with pancytopenia, coagulopathies and bleeding. We describe a case of an unusual presentation of acute promyelocytic leukemia. A 53 year-old male was admitted complaining of pain and weakness in his legs. He presented at examination a spastic paraparesis with a sensitive level at the eighth thoracic medullar (T8) segment. Magnetic resonance imaging showed a posterolateral extradural mass from T6 through T8 segments with medullar compression. A complete blood count showed anemia, thrombocytopenia and the presence of promyelocytes and blasts. Marrow examination was compatible with the diagnosis of acute promyelocytic leukemia by cytogenetics and polymerase chain reaction for the PML-RARα gene. He was treated with all-trans-retinoic acid therapy plus daunorubicin and presented an all-trans-retinoic acid syndrome. Despite hematological remission, the patient presented neurologic deterioration and had to be treated with radiotherapy (total dose 3000 cGy) of the extradural lesion. The patient evolved with severe sepsis and died without any recovery from his neurologic deficit. Extramedullary infiltration is a very rare complication in acute promyelocytic leukemia. Most cases are related to relapse after initial treatment with all-trans-retinoic acid. The skin and the central nervous system are the most frequently involved sites. This is possibly the first case reported of this condition in which the patient had a symptomatic extradural mass.