Variations of cutaneous meningioma have been described as cutaneous heterotopic meningeal nodule (3) and cutaneous meningeal hamartoma (4) or meningothelial hamartoma.
The widely used classification system for cutaneous meningioma was developed by Lopez et al.
6,7) Because of this mechanism, rudimentary meningoceles and acoelic meningeal hamartomas most likely represent 2 ends of a spectrum, (6) and many authors simply prefer the term cutaneous meningioma.
6) An important finding in this type of cutaneous meningioma is the lack of corresponding meningioma of the neuroaxis.
Type III cutaneous meningiomas are tumors that have extended into the dermis or subcutis from a meningioma that involves the neuroaxis (ie, a primary intracranial meningioma).
In an article published in 1992, the authors (14) collected age and site characteristics associated with 92 primary cutaneous meningiomas and found that these tumors tended to present in younger patients with an average age of 34 and a female to male ratio of 4:5.
Type II and III cutaneous meningiomas occur in adults as de novo lesions.
Kalfa et al (21) reported 2 cases associated with a diagnosis of cutaneous meningioma via fine-needle aspiration.
A third group (23) described the fine-needle aspiration findings as a secondary cutaneous meningioma on the scalp of a 45-year-old man with a lesion of 3 months' duration (type III cutaneous meningioma).
Ultrastructural features of cutaneous meningioma are similar to those of intracranial meningioma.
When the diagnosis of cutaneous meningioma enters the differential, careful microscopic examination with the judicious use of selected immunohistochemical stains, especially EMA (Figure, D), can confirm the diagnosis.
In one study, (28) one patient was described with both cutaneous meningioma and pheochromocytoma, although this may have been coincidental as it has not been reported since to our knowledge.