Classification of Cutaneous Meningeal Lesion:

1.  Ectopic meningothelial hamartoma :

Site: Scalp (occipital region)  and spinal cord

Clinical presentation: Congenital lesion. Presents as cutaneous lump in children. No true defect of skull or spinal column is present.
 
Microscopic features:  

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- Lesion is characterized by narrow ectatic pseudovascular spaces lined by epithelioid meningothelial cells present in the dermis and subcutis.  Immunohistochemically , these cells were negative for factor VIII-related antigen and Ulex europaeus lectin but were strongly positive with vimentin and epithelial membrane antigen antibodies, this latter being in keeping with the immunohistochemical profile of meningothelial cells.

- Abnormally dense collagen is present in the backround.

- Irregular strands and clusters of meningothelial cells and variable numbers of psammoma bodies may be present in the collagenous stroma.

- Scattered multinucleate cells may be present.
     
2.  Cutaneous meningioma :

Site: Around sensory organs of the head -Eg. paranasal, orbital and aural.

Clinical presentation: Presents as a discrete nodule in adults.

Microscopic features:
The tumour  is  well circumscribed and more cellular. It is composed of meningothelial cells together with spindle cell areas.  Psammoma bodies and meningeal whorls may be present.

3. Type III lesion :

This lesion represents direct extension or distant metastasis of central nervous system meningioma. The tumour spreads into the skin and subcutaneous tissue usually at the site of previous surgery.

Immunohistochemistry: S100 protein, EMA and Vimentin are positive.

Abstracts: The pathology of extracranial scalp and skull masses in young children. Clin Neuropathol. 2004 Jan-Feb;23(1):34-43. Primary ectopic meningioma.J Indian Med Assoc. 2001 Feb;99(2):102-3, 110. Type 1-primary cutaneous meningioma of the scalp.Eur J Pediatr Surg. 2000 Dec;10(6):387-9. Meningeal hamartoma of the scalp. A variant of primary cutaneous meningioma.Acta Pathol Jpn.1992;42(5):353-7. Hamartoma of the scalp with ectopic meningothelial elements. A distinctive benign soft tissue lesion that may simulate angiosarcoma.Am J Surg Pathol. 1990 Jan;14(1):1-11. Custom Search        Your Ad Here Pathopedia-India.com: Contents ; Introduction of Pathology ; An outline of Diagnostic Techniques available in Pathology ; Cellular Injury ; Diagram showing Structural Changes in Reversible and Irreversible Cell Injury ; Autolysis; Heterolysis ; Necrosis; Coagulation (Coagulative) necrosis ; Caseative (Caseous) necrosis ; Liquefaction necrosis ; Fat necrosis ; Fibrinoid necrosis ; Apoptosis ; Gangrene ; Hyaline Change ; Atrophy ; Hypertrophy ; Hyperplasia ; Metaplasia ; Aplasia ; Hypoplasia ;Cellular Accumulations ; Accumulation of Glycogen, complex lipids and carbohydrates ; Pigments ; Melanin ; Pigments derived from Hemoproteins; Hemosiderin and Hemosiderosis ; Primary Hemochromatosis ; Hematin; Bilirubin.