FOCAL MYOSITIS OF ESOPHAGUS - A DISTINCT INFLAMMATORY PSEUDOTUMOR MIMICKING ESOPHAGEAL MALIGNANCY

Focal myositis is a benign pseudotumor of skeletal muscle that usually occurs in the soft tissue of the extremities. Clinically, it grows ra pidly but usually regresses spontaneously and is often misdiagnosed as a malignancy. We report a case of focal myositis occurring in the upp er esophagus and presenting as a rapidly growing submucosal tumor with severe esophageal stenosis and dysphagia. It was misdiagnosed preoper atively as esophageal malignancy, Histologically, it was characterized by the presence of various-sized skeletal muscle fibers with intersti tial inflammation and fibrosis. The pathological pictures are identica l to polymyositis dermatomyositis, but the stenosis was relieved after operation without recurrence, and levels of the polymyositis-associat ed autoantibodies and serum antibodies and serum enzymes were not elev ated. Therefore, clinical and histological information is needed to ma ke a correct diagnosis.