Immunohistochemical analysis of spinal intradural xanthomatosis developed in a patient with phytosterolemia.

Multiple intradural xanthomatous tumors developed in 48-year-old female with familial phytosterolemia. These tumors were restricted to the spinal denticulate ligaments. Histological and immunohistochemical findings were fundamentally similar to those of tendinous xanthomas. The major cellular component of these tumors were identified as of mono-histiocytic origin because they possessed myeloid histiocytic antigen (Mac 387), CD11c and lysozyme but not CD15. Sitosterols, campesterols and cholestanols were recovered from the extract of the tumors and the lesions were confirmed to be phytosterolemic xanthomas. Schwann cells stained with anti-S100 protein were confined to the perivascular small nerve bundles and did not show xanthomatous change. Although immunohistochemical preparation of epithelial membrane antigen and desmoplakin I+II revealed the presence of non-neoplastic meningothelial cells in the superficial portion of the tumors, they were too few to play a significant role in the development of these xanthomas.