Spinal epidermoid cyst associated with limited dorsal myeloschisis

Abstract

Background: Epidermoid cysts (ECs) are rare benign tumors arising from epidermal cells, associated with congenital abnormalities or acquired through trauma, surgery, or lumbar punctures. They represent <1% of all intraspinal tumors and may be associated with limited dorsal myeloschisis (LDM).

Case description: A 7-year-old neurologically intact male had a dorsal skin mass since birth located posteriorly in the midline of the inferior thoracic spine. The mass was palpable, painless, mobile, vascularized, and could be transilluminated. Thoracic magnetic resonance imaging showed an extensive intradural extramedullary cystic lesion extending from D6 to D8 that did not enhance with contrast, accompanied by a subcutaneous fluid collection at D8-D9 communicating with the subarachnoid space. The patient underwent gross total resection of the lesion, pathologically confirmed as an EC. The postoperative course was uneventful, with no recurrence 1 year postoperatively.

Conclusion: LDM may be associated with ECs. Early diagnosis and surgical resection of these lesions are essential for favorable outcomes.

Keywords: Congenital epidermoid cyst; Limited dorsal myeloschisis; Spine.

Figure 1:

(a) Posterior view of the thoracic meningocele, (b) positive transillumination test.

Figure 2:

(a) Medullary magnetic resonance imaging (MRI) on a sagittal section in T1-weighted sequence ,(b) T2 sequence, (c) and short-tau inversion-recovery showing an extramedullary intradural cyst from D6 to D8 in T1 hyposignal and T2 hypersignal. (d) Spinal cord MRI on axial section in T1-weighted sequence objecting the extramedullary intradural cystic lesion in T1 hyposignal, (e) T2 sequence showing the subcutaneous fluid formation in T2 hypersignal at the level of D8-D9 communicating with the subarachnoid spaces.

Figure 3:

(a) Band of communication of the meningocele with the mass subcutaneously,(b) epidermoid cyst in extramedullary intradural after opening of the dura, (c) epidermoid cyst in candle wax appearance after resection.

Figure 4:

In the histopathological examination, (a) cystic lesion with stratified squamous epithelium (black arrow) (hematoxylin-eosin, ×100). (b) Stained by leukocyte common antigen (LCA), around the cystic lesion with stratified squamous epithelium (LCA, ×100). (c) Stratified squamous epithelium stained with pancytokeratin. Desquamation of keratin from the epithelial lining can be observed (pancytokeratin, ×100) (White arrow), inflammatory cells (black arrowhead).

Figure 5:

At 1-year follow-up, control magnetic resonance imaging of the spine showed no recurrence.