Leiomyosarcoma following therapeutic irradiation for ankylosing spondylitis

Abstract

The occurrence of soft tissue sarcomas following therapeutic irradiation for both benign and malignant conditions is a well recognized, though uncommon, event (Souba et al, 1986; Laskin et al, 1988; Robinson et al, 1988). The majority of these tumours have been classified as malignant fibrous histiocytomas (MFH), with fibrosarcomas and a wide range of other histological subtypes occurring less frequently. Of particular note is the scarcity of reports of leiomyosarcomas that fulfil the criteria for a radiation-induced malignancy. Within the literature, we could find only four such cases, three of which followed the treatment of bilateral retinoblastoma (Lynch & Herr, 1981; Folberg et al, 1983; Font et al, 1983). In this report we present a case of leiomyosarcoma following irradiation for ankylosing spondylitis. In 1987, a 61-year-old Caucasian male presented to a district hospital with a history of upper thoracic back pain that had been present for several years. The patient had been aware of a subcutaneous, non-tender lesion in the upper thoracic paravertebral region for the previous 3 years. A computed tomographic (CT) scan showed a 2–3 cm diameter mass on the right, adjacent to the second and third thoracic vertebral bodies. A biopsy indicated a soft tissue sarcoma but no treatment was offered as the tumour was considered unresectable. Over the subsequent year, the mass fluctuated in size. It then started to grow, with an increase in back and right shoulder pain.