Localized amyloidoma of the chest wall: diagnostic and surgical perspectives

Background An amyloidoma is defined as a solitary, localized, tumor-like deposit of amyloid in the absence of systemic amyloidosis. Amyloidomas occur most frequently in the bladder, followed by the lungs, trachea and bronchi, larynx and vocal cords, tonsils, conjunctivae, orbits, lymph nodes, gastrointestinal tract, and skin. It is extremely rare for an amyloidoma to present in the chest wall. Indeed, only 5 cases of chest wall amyloidoma have been reported. Moreover, all reported lesions were > 10 cm in size and involved the ribs. Herein, we report our experience with a patient who had a chest wall amyloidoma 3 cm in diameter without rib involvement. Case presentation A 3.1 × 1.5-cm tumor situated in the fifth intercostal space of the chest wall was found in an 83-year-old male during a routine health checkup. Chest magnetic resonance imaging showed a mass of intermediate intensity on T1-weighted imaging and low intensity on T2-weighted imaging with heterogeneous contrast enhancement. The tumor was resected during video-assisted thoracoscopic surgery. No adhesions were observed between the tumor and the lung. The tumor was white, hard, elastic, and located in the extrapleural fat without bone involvement. The tumor was removed in a piecemeal fashion because the tumor was fragile and the surgical margin was unclear. A wide resection was achieved, including the intercostal muscle. Pathologic examination of the tumor using Dylon and Congo red staining confirmed amyloid deposition with tumor spread from the fat to the intercostal muscle and vascular walls but no pleural invasion. Without clear evidence of systemic amyloidosis, this patient was diagnosed with an amyloidoma of the chest wall. The postoperative course was uneventful, and he is doing well 1 year after surgery. Conclusion Amyloidoma of the chest wall can present in various ways. An amyloidoma can be a small tumor, as in our patient, or the amyloidoma can be a large, destructive mass with rib involvement. Diagnosis of an amyloidoma should be kept in mind when patients present with chest wall tumors because an amyloidoma can be characterized by invasion within the chest wall independent of size.