Osteochondroma is the most common benign bone tumor, representing 15% of all bone tumors [
10] and 45% of benign bone tumors [
11]. It is common in young patients, usually below 30 years of age, with a ratio of males to females of >1.5:1 [
12]. Although its etiology is still unknown, osteochondroma is known to be a sessile or pedunculated cartilage-capped bony projection arising on the external surface of the bone which contains a marrow cavity that is in continuity with that of the underlying bone [
7,
12]. Osteochondroma is usually painless, but symptoms may result from complications such as mass effect that produce mechanical pressure, restriction of motion, fracture of the bony stalk of the tumor, nerve impingement syndromes and large bursal formation [
2,
7,
13]. Malignant transformation to chondrosarcoma is a very rare event, reported to have an incidence of approximately 1% and characterized by a sudden increase in size of the lesion accompanied by pain, usually described as severe [
7]. Growth of osteochondromas typically ends at the time of closure of the physis; growth during adulthood should raise concern for possible malignancy. In addition a cartilaginous cap thinner than 1cm usually indicates a benign condition, whereas a cap between 1 and 2cm may be considered questionable, and a cap thicker than 2cm generally is a sign of malignant transformation [
7]. Although proximal humerus, distal femur and proximal tibia are the commonest sites by far (90%), involvement of the flat bones has been reported and scapular lesions account for 4% of all described osteochondroma [
11]. Very few tumors arise from the ventral surface of the scapula and they can result in painful limitation of shoulder abduction and pseudowinging of the scapula as in our case. The diagnosis needs a well-steered anamnesis and a careful clinical examination which generally highlights a bony painless mass, considered to be the most frequent presentation of osteochondroma. Patients with an osteochondroma of the scapula may present with other common complaints which include pain, decreased active ROM and crepitus with movements of the involved shoulder [
8,
14]. In other cases, the diagnosis is made incidentally, resulting from X-rays. A plain radiograph is the main diagnostic examination. Anteroposterior and lateral radiographs are generally sufficient to make the diagnosis, but a CT scan usually provides help in characterizing the lesion and planning the treatment, in particular for tumors of the pelvis and scapula. Magnetic resonance imaging is usually saved for cases in which malignant transformation is suspected [
7]. The treatment of choice for this kind of tumor is usually open surgery, which does not show any complication when the glenohumeral joint is preserved [
15]. Tumor relapse is very rare and usually occurs when unclear resection margins are left [
16]. At present, endoscopic resection is considered to be a good option in selected cases as it provides earlier functional recovery and better results in terms of pain relief, post-resection performance and cosmetic outcome [
9,
16,
17].