[Case of intraspinal epidural tumor developing after systemic mastocytosis with marked osteosclerosis and...

A 64-year-old man was diagnosed as having urticaria pigmentosa in 1998, and treated with PUVA therapy. In January 2002, X-ray imaging revealed osteosclerosis was detected in the systemic bone and bone scintigraphy. A bone marrow aspiration sample was not obtained due to a dry tap. CT scans showed hepatosplenomegaly and mesenteric lymphadenopathy. Myelofibrosis and diffuse mast cell infiltration were revealed by a bone marrow biopsy, and a diagnosis of systemic mastocytosis with severe osteosclerosis and myelofibrosis was made. In October 2003, he was admitted to our hospital because of mid back pain. A neurological examination showed muscle weakness in the upper and lower limbs, sensory disturbance below the level of Th4 and urinary obstruction. T1 and T2 weighted images of MRI demonstrated a high intensity epidural mass lesion extending from the vertebral level of C5 to Th2 and severely compressing the spinal cord. We considered the possibility of the invasion of the spinal canal by the mastocytosis. The patient was treated with interferon alpha-2b (IFN-alpha2b) and prednisolone. Subsequently, the motor and sensory disturbances were gradually alleviated, and spinal MRI confirmed a marked reduction in the size of the epidural tumor. However, the patient became resistant to interferon, and died of multiple organ failure in spite of steroid pulse and cladribine therapies. Multiple organ infiltration by mast cells was revealed at autopsy.