BACKGROUND: This report describes the pathology of an unusual variant of fibroma of the eyelid. The soft ovoid tumour was excised from the centre of the left lower lid in an 84-year-old patient had been growing slowly for several years. METHODS: The tumour was studied by conventional histology, immunohistochemistry and electron microscopy. RESULTS: The tumor was formed by fibroblasts of spindle and multinucleate type, and the collagenous stroma contained mast cells and blood vessels which exhibited minor inflammatory changes. With the immunohistochemical methods the only positive marker was for vimentin. CONCLUSION: On morphological grounds it was possible to distinguish this extremely rare tumour from other mesenchymal tumours. The presence of distinctive multinucleate giant cells makes the term pleomorphic fibroma an appropriate name for this type of lesion.