Midline Spinal Cord Hamartoma
- Background:
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Spinal hamartomas are rare, benign spinal lesions that occur most commonly in children with neurofibromatosis type 1 or dysraphism. The lesions consist of well-differentiated, mature tissue in an abnormal location, different from those found in NF1.
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In patients with NF1, there is proliferation of glial cells, ganglion cells, disoriented axons, and vessels within the spinal cord.
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Midline spinal cord hamartomas may have adipose tissue, cartilage, bone, lymphoid tissue, synovial membranes, glandular tissue, abnormal vessels, and urinary tract tissue.
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The suggested mechanism by which spinal hamartomas form is both premature and incomplete disjunction of the neural tube from the overlying ectoderm.
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- Clinical Presentation:
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Spinal hamartomas can be located anywhere along the spinal cord. Most patients are asymptomatic and the diagnosis is incidental.
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Patients may have an overlying skin lesion/defect.
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- Key Diagnostic Features:
- Spinal hamartomas are usually asymptomatic and are easily differentiated from other lesions with MRI.
- They are solid, exophytic, focal lesions that are isointense to the spinal cord, with no enhancement, edema, or mass effect.
- Biopsy may be considered to confirm the diagnosis.
- Differential Diagnoses:
- Dermoid: appears bright on T1WI; similar in appearance to an intraspinal lipoma
- Teratoma: contrast enhancement and signal inhomogeneity
- Epidermoid: similar signal intensity to fluid on both T1WI and T2WI
- Astrocytoma: central intramedullary lesion (not exophytic) with increased T2 signal; may have intratumoral cysts and variable contrast enhancement
- Treatment:
- Surgery can be carried out to fix a cosmetic skin defect overlying the lesion or to prevent infection or cord tethering.
