Rudimentary Meningocele of the Scalp

Rudimentary meningocele, a variant of primary cutaneous meningioma, is a rare embryologic malformation with meningeal tissue occurring in the skin. This work studied five cases of this condition. All five cases were congenital and presented as alopecic lesions on the occipital area. No underlying bony defect or communication to the intracranial compartment was detected by brain computed tomography (CT) or echoencephalogram. Histologically, the major changes were mostly concentrated in the subcutis, where strands of meningothelial cells were embedded in dense collagenous tissue. The meningothelial cells were immunopositive for vimentin and epithelial membrane antigen and lacked cytokeratin, S-100 protein, smooth muscle actin and endothelial markers. The related literature also was reviewed. (Dermatol Sinica 21 : 394-401, 2003)