Intramedullary Mature Teratoma

Background:

• Teratomas encompass a variant of multipotential cell tumors that contain mesodermal, ectodermal, and endodermal elements.
• They are classified as mature, immature, or malignant by virtue of the degree of differentiation of said elements. The incidence of spinal teratomas is rare accounting for only 0.15–0.18% of spinal tumors.¹
• The rarity supercedes in the adult population whereas in the pediatric population spinal teratomas account for nearly 5–10% of spinal neoplasms.

Clinical Presentation:

• On account of the more localized occurrence of spinal teratomas in adult population, clinical features encountered include numbness or weakness of either or both the lower extremities, which may occasionally be accompanied by pain.²
• This is in contrast to pediatric intraspinal teratomas, where the nonspecificity of clinical features is often aided by features of progressive scoliosis and skin findings pointing toward spinal dysraphism, which are strong associations of this tumor in the pediatric cohort.

Key Diagnostic Features:

• Intraspinal teratomas are well-encapsulated solid-cystic lesions that display variable signal intensities with the following characteristics: the fatty component demonstrates hyperintense signal on T1- and T2WI and hypointense signal on fat-suppressed sequences; foci of calcification mostly display hypointense signal on all sequences and often show only mild enhancement; last, they are often associated with congenital dysraphic spinal anomalies, particularly in the pediatric cohort.

Differential Diagnoses:

• The classic feature of spinal epidermoid cysts is diffusion restriction and they are unlikely to contain intralesional fat.
• Spinal lipomas show homogeneously hyperintense signal on T1- and T2-weighted images and signal suppression on fat-saturated images. Also, diffusivity is not impaired.
• Spinal arachnoid cyst and spinal neuroenteric cyst demonstrate CSF signal on all sequences with the latter being located ventrally to the spinal canal and frequently associated with vertebral fusion anomalies.

Treatment:

• Total surgical resection is the foremost therapeutic option for symptomatic patients. Teratomas exhibit adhesion to the adjacent neural tissue in approximately 50% of cases making complete resection challenging, however because subtotal resection increases the chance of recurrence, it is advised to remove the tumor as much as possible while preserving the neural tissue. Precaution should be taken to prevent contents of the cystic lesion from leaking into the intradural space to prevent chemical meningitis and complications like hydrocephalus.³