Chest Wall Fibromatosis in the Axilla

Fibromatosis is a rare tumor that is caused by the proliferation of well-differentiated fibroblasts. Two-thirds of all fibromatosis is abdominal. After the abdomen, the shoulder and pelvis are the parts of the human body where fibromatosis occurs most frequently [1]. It invades adjacent tissues and has a recurrence rate of 10% to 90% after excision, even though it is histologically a non-metastatic benign tumor. While fibromatosis in the shoulder, pelvis, mesenterium, head, and neck have been reported, fibromatosis in the axilla is very rare. We report a case of chest wall fibromatosis with left arm involvement that was successfully treated by function-preserving surgery. A 39-year-old female had experienced paresthesia including numbness for 2 years and by chance was found to have a mass at the left axilla during a breast ultrasonography. As the patient had no accompanying symptoms with the left arm numbness, conservative treatment was carried out with monitoring of progress. During the conservative treatment, it was noted that the frequency and intensity of numbness gradually increased and a limited range of motion of the left arm was noted. Physical examination of the left axilla was unremarkable. However, upon careful palpation, a 2×5 cm hard, fixed, oval-shaped painless mass was detected. Erythema or a heating sensation and tenderness were not evident surrounding the mass (Fig. 1). Laboratory and radiologic findings showed no abnormality. On T1 weighted magnetic resonance imaging, a 3×7 cm benign tumor with low signal intensity tightly connected to the chest wall and positioned in front of the subscapularis muscle of the left axilla was observed. Invasion of the chest wall and ribs were not noted and the major neurovascular bundle was not invaded (Fig. 2). Under general anesthesia, for a sufficient operative view, an S-shaped skin incision was made and displaced medially. Following the anterior displacement of the pectoralis major and minor muscles, the mass, except the vital structure area, was exposed and excised by the Enneking staging method [2]. The intercostal muscle and perichondral tissue were also removed together, preserving the pleura and brachial