[Intraosseous neurinoma]

A case of neurilemmoma in bone localized in the proximal phalanx of the right thumb is described. There are less than 40 cases of this typoe of tumor to be found in the literature. The majority of them were localized in the jaw and maxillary bones. The tumor usually grows slowly, histories of up to 20 years duration being described. Clinical symptoms are not characteristic. X-ray examination shows cystic bone defects. The origin of the neurilemmoma in bone is believed to be cells of SCHWANN of the paravasal nerves, which accompany the nutrient artery. Microscopically two types of cells can be distinguished in the tumor. The neurilemmoma in bone is probably always benign. The therapy of choice is local excision of the tumor.