Collagenous fibroma of the deltoid muscle: clinical, surgical and histopathological aspects.

We report the case of a 66-year-old woman with a tumorous swelling of the right shoulder of approximately 6 months' duration with morphological features consistent with desmoplastic fibroblastoma or collagenous fibroma, a benign fibrous soft tissue tumor with distinct clinico-pathological features. Clinical history, radiological and pathological findings are presented and other cases of collagenous fibroma with unusual location are discussed.