Epidemiology
Also called collagenous fibroma, it appears as a benign deep-seated mass in adults. It is usually a firm, minimally painful mass; MRI helps show its fibrous content and its borders.
Basic features
It usually grows slowly in the limbs, shoulder girdle, or trunk and can feel firm because of its abundant collagen. Unlike a desmoid tumor, it does not infiltrate aggressively and does not share that tumor's tendency to recur.
Usual treatment
Marginal resection is curative in most cases. It is indicated when the lesion causes symptoms, grows, or leaves diagnostic doubt.
Outcomes and prognosis
The outlook is excellent: it is a benign lesion that does not metastasize and, once removed, practically never comes back, so it does not require prolonged follow-up.