Postirradiation malignant fibrous histiocytoma arising in juvenile nasopharyngeal angiofibroma and producing alpha-1-antitrypsin.

A fatal nasopharyngeal malignant fibrous histiocytoma developed in a young male after irradiation of juvenile nasopharyngeal angiofibroma diagnosed 5 years earlier. The sarcoma extended from the nasopharynx into the floor of the pituitary fossa and into both parasellar regions. There was no clinical evidence of any distant spread. Many of the malignant cells contained cytoplasmic granular and globular PAS-positive inclusions shown to be alpha-1-antitrypsin immunohistochemically. Ultrastructurally, this probably corresponded to electron-dense material with distinctive patterns and which had accumulated within distended ergastoplasmic cisternae of the neoplastic cells. Three previously reported case of postirradiation sarcomas arising in nasopharyngeal angiofibroma were said to be fibrosarcomas and none produced alpha-1-antitrypsin.