Malignant transformation of intrathoracic ancient neurilemoma in a patient without von Recklinghausen's disease.

A case of intrathoracic ancient neurilemoma undergoing malignant change in a 48-year-old woman is reported. The lesion was first discovered incidentally during routine roentgenologic examination of the chest 15 years before its surgical removal. The gross and histologic examination of the tumor showed the features of ancient neurilemoma with extensive regressive changes as well as small preserved areas composed of Antoni type A and B tissues. In addition, obviously histologically malignant foci manifested by the presence of increased cellularity, active mitotic activity, and gradual loss of orginary neurilemomatous differentiation were present. The patient died 16 months after operation of recurrent and distant metastatic disease. At autopsy, there was no evidence of generalized neurofibromatosis or other primary cancer. A review of the available literature revealed only two other similar cases documenting malignant transformation of solitary benign neurilemomas in patienets without von Recklinghausen's disease.