Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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March 18, 2021
Intradural Spinal Mature Teratoma
- Background:
- Spinal dermoid cysts arise from chaotic differentiation of pluripotent somatic cells and can contain developed tissue from all 3 germ cell layers.
- Teratomas have been described in association with spinal malformations, such as spina bifida, dermal sinus, myelomeningocele, and diastematomyelia (split cord syndrome).
- Clinical Presentation:
- Spinal teratomas are exceptionally rare in adults and are more common in children.
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Although they are often found incidentally, they can present with nonspecific symptoms from mass effect such as insidious-onset pain, numbness, and extremity weakness.
- Key Diagnostic Features:
- Spinal teratomas are typically intradural, extramedullary tumors located midline and most commonly in the thoracolumbar region, whereas 40% are intramedullary.
- The imaging appearance is variable, and MRI demonstrates the characteristics of the lesion, including cystic components that are T1 hypointense and T2-FLAIR hyperintense, which may also show fluid-fluid levels, sebaceous portions demonstrating T2 hypointensity due to the presence of cholesterol esters, T1-hyperintense elements of fat, soft-tissue components, calcifications, and hemorrhage. The enhancement may be minimal to heterogeneous.
- When associated with diastematomyelia, characteristic vertebral anomalies may include multilevel spina bifida, hemivertebrae, butterfly vertebrae, and scoliosis.
- Differential Diagnoses:
- Cystic meningioma: Homogeneously enhancing intradural mass that may display a dural tail. These lesions are typically round in shape and follow spinal cord signal on MRI, although calcification and hyperostosis may be visualized.
- Epidermoid cyst: Presents as a hypodense mass typically located within the lumbar region. Epidermoid cysts are usually round or oval, follow CSF signal on MRI, and display restricted diffusion. These lesions are less likely to contain calcification.
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Complex arachnoid cyst: Characterized as a well-circumscribed, homogeneous lesion that demonstrates CSF intensity on MRI and lacks diffusion restriction. These are typically oval in shape and may demonstrate mass effect on the spinal cord.
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Spinal schwannoma: The most common intradural, extramedullary mass, which can be seen as a dumbbell-shaped mass originating from the spinal nerve roots and extending into and remodeling the neural foramina. These lesions are typically well circumscribed, displace nearby structures, and may be heterogeneous from cyst formation, patchy enhancement, or fatty degeneration.
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Neurofibroma: Solitary or multiple spinal neurofibromas are seen in patients with neurofibromatosis type 1. A classic finding is a “target sign,” which is an area of T2 hypointensity with surrounding hyperintensity.
- Treatment:
- The treatment of choice is complete resection with the capsule intact. Incomplete resection is a common occurrence.
