Aim: Alveolar soft part sarcoma is a very rare tumour. Nine cases are reviewed in order to identify new aspects of this tumour.
Methods and results: The clinical course, histological, immunohistochemical and ultrastructural features of nine cases of alveolar soft part sarcoma were reviewed. Proliferative activity and p53 protein accumulation were assessed immunohistochemically. The patients were aged between 18 and 70 years. In the cases with sufficient follow-up, survival was variable with two patients dying within 5 months and four alive at 4 years. Histologically all tumours had an alveolar component but one case also had a spindle component and another case had a pseudoglandular pattern. Six cases showed desmin immunoreactivity, one was muscle-specific actin positive, two were positive for S100 protein and three were positive for vimentin. MIB-1 immunostaining was seen in up to 35% of cells. Two cases showed p53 protein accumulation.
Conclusions: There appeared to be no correlation between short term survival (4 years or less) and clinical presentation, adjuvant treatment, tumour size, histological grade, vascular invasion by tumour, proliferative index, or p53 protein accumulation. Although unusual, spindle cell or pseudoglandular components can be seen in alveolar soft part sarcoma.