[Multinucleated cell angiohistiocytoma. Report of 6 cases]. / Angiohistiocytome à cellules multinucléées. A propos de six cas.

Multinucleate cell angiohistiocytoma is a recently described entity. It is a benign vascular proliferation. Clinically, it is characterized by violaceous red papules, often mimicking Kaposi's sarcoma. Acral sites and face were the commonest sites. The six patient's age was between 41 and 64 years and sex ratio was equal. Microscopic features were an increased number of blood vessels together with mononucleated and multinucleated histiocyte-like cells with scalloped borders. Staining of mononucleated cells with CD68, anti vimentin and anti factor XIIIa antibodies emphasized a fibrohistiocytic origin. Loss of factor XIIIa expression in multinucleate cells gets clue to think that these cells are dedifferenciated.

[Spinal melanocytic schwannoma with malignant course. Microscopic and ultrastructural study of a case]. / Schwannome mélanocytique spinal d'évolution maligne. Etude microscopique et ultrastructurale d'un cas.

The authors report a case of recurrent pigmented intraspinal schwannoma with malignant progression. Electron-microscopic study confirmed that melanin pigment was produced by tumor cells and that these cells were derived from the nerve sheath. The histogenesis of pigmented tumors is explained by their neural crest origin and the problem of differential diagnosis of the malignant form with melanoma is discussed.