Granulocytic Sarcoma of the Spine: MRI and Clinical Review

Granulocytic sarcoma is a tumor formed by myeloid precursors at an extramedullary site. The purpose of this study was to evaluate the MRI findings and clinical manifestations in 32 cases of granulocytic sarcoma of the spine. Thirty-two patients (21 males, 11 females; mean age, 32 years) with myeloid leukemia and spinal granulocytic sarcoma were included in this study. All of the patients underwent radiotherapy with chemotherapy, and four patients underwent surgical decompression or excisional biopsy. All 32 patients underwent MRI of the spine; 21 patients underwent follow-up MRI. Nine patients had spinal granulocytic sarcoma in the initial manifestation of leukemia. The other 23 diagnoses were made during a remission or relapse period. The lumbosacral and thoracic portions of the spine were commonly involved. Twenty-seven patients had multiple or contiguous multilevel involvement. According to location, spinal granulocytic sarcoma was classified as epidural in the central spinal canal, epidural along the nerve course, thickening of the nerve root itself, or prevertebral. Lesions were seen as isointense on T1-weighted images and had intermediate signal intensity with homogeneous enhancement on T2-weighted images. Nine patients had complete reduction of the tumor volume, and 12 patients had partial reduction. The median survival period was 9 months, and the 1-year survival rate was 41%. Knowledge of the imaging findings of spinal granulocytic sarcoma, which consists of multiple extramedullary masses with diffuse leukemic bone marrow infiltration, can lead to early diagnosis and appropriate treatment to reduce neurologic symptoms.