Desmoid tumor of the subscapularis presenting as isolated loss of external rotation of the shoulder. A report of two cases.

Abstract

Isolated loss of external rotation of the shoulder with the arm at the side is a rare clinical finding in patients presenting with a shoulder problem. Most patients with shoulder stiffness are first seen with a loss of mobility involving at least two planes of motion that usually results from primary or secondary adhesive capsulitis1,2. Soft-tissue tumors of the shoulder girdle are rare3. Among soft-tissue tumors, desmoid tumors are very rare and they most frequently occur in the shoulder girdle and the thigh of adolescents and young adults4. Desmoid tumors are slow-growing benign fibrous neoplasms arising from soft tissue and muscle. They have a notoriously high recurrence rate5,6. Adequate surgical resection can be challenging, and early diagnosis is intuitively beneficial in facilitating surgical management before the tumor has invaded and distorted the regional anatomy. We present the cases of two patients with a desmoid tumor originating in the subscapularis muscle who were first seen with vague progressive shoulder pain and a clinical examination pertinent for only marked limitation of active and passive external rotation of the shoulder with the arm at the side. The patients were informed that data concerning their cases would be submitted for publication. CASE 1. A fifty-three-year-old woman who was right-hand dominant and worked as an administrator presented with progressive pain in the left shoulder, including mild night pain, of insidious onset occurring over a two-year period. The pain was described as a dull ache of variable intensity deep within the shoulder. She reported that she had not had any fevers or other systemic symptoms. The only prior treatment was a subacromial injection of lidocaine and corticosteroid, which had been given by her primary care physician, and it had provided no relief. Plain radiographs …