Desmoids are uncommon mesenchymal tumours that occur at single or multiple anatomical sites, occasionally in association with polyposis coli. This paper describes the use of the triphenylethylene tamoxifen, and a new chlorinated analogue, toremifene, in 20 patients with progressive desmoid disease. Clinical responses ranging from stabilisation of disease to complete resolution were observed in 65% of cases. The antitumour activity of this group of drugs has been attributed to their anti-oestrogenic behaviour. However, desmoids provide a clinical model of a purely mesenchymal tumour which appears to respond despite having generally low levels of hormone receptor. This emphasises the significance of stroma within breast (and other) tumours, in particular how the stroma may regulate the response to these drugs regardless of receptor status.