Extrarenal rhabdoid tumor is a rare, highly aggressive tumor of childhood with a poor prognosis. It represents <1% of pediatric soft tissue malignancies, typically involving infants . Frequently involved extrarenal sites include deep locations of the neck, abdomen, and paraspinal regions. The presence of "rhabdoid" cells is the characteristic histologic feature. Recent discovery of a specific genetic mutation enables a more accurate diagnosis. We present a case in an adolescent of extrarenal rhabdoid tumor arising within the sacral canal. This appears to be the first reported case of an extrarenal rhabdoid tumor arising within the sacral canal and mimicking a peripheral nerve sheath tumor. While rare, this tumor can be included in the radiologic differential diagnosis of peripheral nerve sheath tumors in children.

SUMMARY: An 8-month-old boy with Gorlin syndrome presented with a large right-face turn and constant exotropia of the left eye. Eight-millimeter recession of the left lateral rectus muscle was performed at 23 months of age without complete postoperative improvement. Orbital imaging revealed bilateral anomalous extraocular muscles inferolateral to the optic nerves. Surgical resection of the tissue confirmed the accessory musculature with postoperative correction of the strabismus. To our knowledge, this appears to be the first reported case in the radiologic literature.

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