Desmoid tumour of the breast as a manifestation of Gardner's syndrome.

INTRODUCTION: Desmoid tumours of the breast are rare. Although benign, they can mimic breast cancer on physical examination, mammography and breast ultrasound and can also be locally invasive. Even though they occur sporadically, they can also be seen as a part of Gardner's syndrome. We describe a case of desmoid tumour in a woman with Gardner's syndrome where the lesion was mammographically occult. PRESENTATION OF CASE: A 63-year old woman presented with four months history of a painful left breast lump. She had a screening mammogram seven months ago which was normal. She is known to have Gardner's syndrome and had a total colectomy, she has also had multiple abdominal desmoids excised in the past. On examination there was a 4cm×5cm firm, mobile lump in the left breast. Her mammograms in the clinic were also normal. Ultrasound suggested a benign lesion of the breast and a core biopsy showed it to be a benign spindle cell lesion. She underwent wide local excision of the lump, the intraoperative mammograms of the excised specimen also failed to detect the lesion. Histopathology of the excised specimen confirmed the tumour to be a benign desmoid tumour. She has now been offered radiotherapy and nonsteriodal anti-inflammatory drugs (NSAIDs) to reduce her chances of a local recurrence. CONCLUSION: A high index of suspicion and a thorough triple examination protocol is necessary to detect rare lesions like a desmoid tumour which can masquerade as breast carcinoma.