RESUMEN
BACKGROUND: Systemic mastocytosis is a mast cell proliferative disorder affecting many organs that is rarely associated with internal bleeding. OBJECTIVE: To describe a case of spinal epidural hematoma in a patient with past medical history of urticaria pigmentosa and osteoporosis diagnosed with systemic mastocytosis. CASE REPORT: A 63-year-old woman with urticaria pigmentosa was admitted to hospital for severe back pain after minor trauma. Physical examination showed pain on pressing T12 and L1 spinous processes, bilateral Lasègue sign, absent ankle jerk, and extensor plantar response. Computed tomography disclosed L3 fracture, and magnetic resonance imaging revealed spinal epidural hematoma and T2 hyperintensive scattered vertebral foci that suggested malignancy. The 24-hour urine histamine was very high. Mast cell infiltration was found in bone marrow biopsy. Because power was normal and there was no clinical sphincter disorder, the patient was successfully treated with conservative care. CONCLUSIONS: To our knowledge, acute intraspinal epidural hematoma has never been associated with mastocytosis. The hematoma was likely related to the vertebral fracture as well as a hemorrhagic diathesis due to anticoagulants released by local mast cells.