Mesenchymal differentiation in trigeminal neurilemmoma.

An unusual neurilemmoma of the trigeminal nerve in a 31-year-old woman is described. The neoplasm was roentgenographically calcified and contained various types of mesenchymal tissue, including a cavernous angioma, cartilage, bone, and adipose tissue. Angioma in combination with neurilemmoma occurs more frequently than other forms of mesenchymal tissue. Lipoma is an uncommon component of neoplasms affecting the cranial nerves. Cartilage and bone are rarely encountered in benign intracranial neurilemmomas. The histogenesis of this combined neoplasm is discussed in relation to the ectomesenchymal properties of the neural crest.