Sacral myolipoma with symptomatic contraction of the conus at standing on tiptoe.

INTRODUCTION

We present a case with spinal myolipoma that was unique in its anatomical composition and symptomatology.

CASE REPORT

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.

CONCLUSION

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.