title: Sacral myolipoma with symptomatic contraction of the conus at standing on tiptoe.
abstract: BACKGROUND
  We present a case with spinal myolipoma that was unique in its anatomical composition and symptomatology.
  
  
  METHODS
  An 18-year-old male presented with urinary retention and buttock pain exacerbated by standing on tiptoe underwent untethering of the low-set conus associated with a sacral fatty tract. Electrical stimulation of the spinal roots beside the upper conus induced anomalous caudal movement of the conus and contraction of the gastrocnemius muscle. In the lower conus, an ectopic muscle bridging the conus and dura was found, and the tissue contracted upon electrical stimulation. The histopathological diagnosis was myolipoma involving mature striated muscle and fat cells. Postoperatively his buttock pain was relieved immediately, but urinary retention persisted.
  
  
  CONCLUSIONS
  We posit that his buttock pain, exacerbated by standing on tiptoe, was due to traction of the conus by contraction of the ectopic muscle that was aberrantly innervated from the sacral spinal roots.
authors: Department of Neurosurgery, Yokohama Stroke and Brain Center, l-2-1 Takigashira, Isogo-ku, Yokohama, Kanagawa, 235-0012, Japan, Satoru4756@aol.com.
authors: Satoru
authors: S
authors: Shimizu
authors: Tomoko
authors: T
authors: Miyazaki
authors: Takahiro
authors: T
authors: Mochizuki
authors: Hidehiro
authors: H
authors: Oka
mesh_terms: D000293:Adolescent; D006801:Humans; D008067:Lipoma / Q000473:pathology* / Q000601:surgery; D017116:Low Back Pain / Q000209:etiology; D008297:Male; D011187:Posture; D012447:Sacrum / Q000601:surgery; D013120:Spinal Cord Neoplasms / Q000473:pathology* / Q000601:surgery; D001750:Urinary Bladder, Neurogenic / Q000209:etiology; D016055:Urinary Retention / Q000209:etiology
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