Lingual alveolar soft part sarcoma; 14 cases: Novel clinical and morphological observations

Aims: Alveolar soft part sarcoma (ASPS) is a rare sarcoma in the buttocks or thigh of young adults, often with metastases to lung, brain, or bone. This study examines the morphological and clinical features of lingual ASPS. Methods and results: Fourteen cases, in eight males and six females (ages 3-21 years, median 5 years), ranged from 8 to 50 mm, median 25 mm. All tumours were intramuscular, circumscribed and multinodular. Tumours from all but the oldest patient exhibited a predominantly solid (non-alveolar) growth pattern. Vascular invasion was common. Crystals varied in number from none or extremely rare to nearly 100% of tumour cells. Immunohistochemical results: Fifty percent desmin positive, all focally smooth muscle antigen (SMA) positive; negative for vimentin, neural/melanocytic, myoid, histiocytic, and epithelial markers. All tumours were surgically excised; only two patients received chemotherapy. Follow-up on 10 patients showed that all patients were alive without disease (4-32, median 22 years). Only one patient had a microscopic metastasis to lung (3 years) but was without disease at 11 years. Conclusions: Lingual ASPS is a tumour of childhood with a distinctive, predominantly solid growth pattern. Despite typical vascular invasion, the early diagnosis and small tumour size may explain its relatively good outcome.