The case of a giant thoracic desmoid tumour in a 44-year-old woman, who presented two years following a breast reconstruction with a latissimus dorsi (LD) flap and implant, is reported. Clinical findings included a rapidly growing, painless mass. Computed tomography (CT) suggested skin and intercostal soft tissue invasion. The tumour was resected en bloc with the LD muscle, implant capsule and underlying rib segments. The resultant thoracic and abdominal wall defects were reconstructed with Dualmesh® and polypropylene meshes respectively. There was no evidence of recurrence at thirty-six months follow-up.