With an incidence of less than 0.3 per cent, post-radiation sarcomas are rare malignant neoplasms with a very poor prognosis. On average, they occur after a latency period of at least 15 years following radiation therapy with doses ranging from 24 to 80 Gy. We present the case of a post-irradiation malignant fibrous histiocytoma (MFH) on the floor of the mouth in a 79-year-old male patient arising only five and a half years after radiation therapy. The primary tumour was classified as a well differentiated squamous cell carcinoma of the right rim of the tongue. Primary therapy was surgical resection of the tumour and post-operative radiation with 50 Gy. Five and a half years later, the patient developed a rapidly progressing MFH within the field of radiation.

A rare case of cellular benign fibrous histiocytoma (BFH) of the external auditory canal is presented with a discussion of its pathology and management.

Malignant fibrous histiocytoma (MFH) is a common neoplasm of soft tissue. The floor of the mouth is an unusual site of origin and has not been described in the literature previously. Its rarity, aspecific clinical symptoms and complex histopathology combine to make the diagnosis difficult. The treatment of choice is wide surgical excision with adjunctive irradiation.