Aneurysmal bone cyst (ABC) is a rare, benign but locally aggressive bone lesion, most commonly affecting the metaphyseal regions of long bones and the spine. Scapular involvement is extremely uncommon, accounting for less than 3% of cases. We describe the case of a massive, aggressive ABC of the scapula in a 23-year-old female presenting with progressive shoulder pain and a large anterior–posterior mass causing significant functional limitation. Radiographic and MRI findings initially suggested a telangiectatic osteosarcoma. Histopathological analysis confirmed the diagnosis of aneurysmal bone cyst. The patient underwent staged surgical curettage through combined anterior and posterior approaches, followed by rehabilitation. Despite initial improvement, MRI at six months revealed local recurrence, necessitating a total scapulectomy with humeral suspension. Postoperative recovery was satisfactory, with preservation of elbow and hand function and no evidence of recurrence at one year. This case highlights the diagnostic difficulties of scapular ABC due to its radiologic overlap with malignant lesions and the therapeutic challenges imposed by its location. Radical excision remains the definitive treatment for recurrent or extensive forms, offering durable local control and acceptable functional outcomes when reconstructive options are limited.