[Desmoid tumor of chest wall--an important differential diagnosis to malignancies].

Desmoid tumors are rare solid tumors that arise from musculoaponeurotic tissues. They are classified as benign as they do not metastasize. Desmoid tumors can, however, exhibit rapid local growth and clinically they can mimic sarcomas. Their histological appearance can also resemble some malignant neoplasms such as low grade sarcomas, rendering the differential diagnosis difficult. The present report describes a 60-year-old woman with a history of left mastectomy, performed for a lymph node negative adenocarcinoma. At follow-up 4 years later, a solid nodule was palpated below the right breast. The tumor increased in size over several weeks and caused local radiating chest pain. Clinically a breast cancer metastasis was suspected. Open biopsy revealed a desmoid tumor. The tumor was resected together with a part of the anterior hemithorax, and the defect in the chest wall covered with a Goretex-patch. Six months postoperatively, the patient is doing well with no signs of locally recurrent disease.