A CASE OF A PRESACRAL MYELOLIPOMA: IMAGING FINDINGS AND DIFFERENTIAL DIAGNOSIS CHECKLIST OF OTHER PRESACRAL MASSES

PURPOSE: There have been many reports describing adrenal myelolipoma but there have been only few reports of extraadrenal myelolipoma. We describe a case of an elderly woman with lower back pain due to age-related spondyloarthrosis and mild discopathy with a presacral myelolipoma as incidental finding. We also discuss about common and uncommon imaging findings of other presacral masses. METHODS: A 74 years-old woman came to our observation to perform an MRI of the lumbar spine for typical lumbar back pain. MR imaging revealed, in addition to the signs of mild scoliosis and spondylo-disc-arthrosis, a presacral mass showing heterogeneously high signal in all sequences and almost completely suppressed on inversion recovery sequences for fat tissue and not showing significant enhancement after i.v. administration of contrast medium. CT imaging confirmed the fatty nature of the lesion without any sign of bone involvement. RESULTS: CT and MR imaging findings were most consistent with a diagnosis of a rare presacral myelolipoma. Our hypothesis was confirmed at histopathologic analysis which showed a mixture characterized predominantly by mature adipocytes and hematopoietic cells including erythroid, myeloid, and megakaryocytic elements without mesenchimal tissue elements. CONCLUSIONS: We have reported a case of one of the rarest presacral masses and we have emphasized the role of imaging in the differential diagnosis of other presacral masses inclunding liposarcomas, teratomas, dermoids, epidermoids, chordomas, schwannomas and anterior sacral meningoceles.