An Intramuscular Chondrolipoma of the Scapula: A Case Report of a Rare Tumor in an Unusual Location.

Introduction: Chondrolipomas are rare benign mesenchymal tumors primarily occurring in the shoulder region. To the best of our knowledge, only one case of chondrolipoma arising from the shoulder has been reported. We herein report an intramuscular chondrolipoma located in an unusual area of the scapula. Our case is interesting because magnetic resonance imaging (MRI) that shows lipomatous tumor masses with cartilaginous nodules may mislead surgeons into not considering the possibility of chondrolipomas.

Case Report: A 62-year-old female, without any systemic disease, trauma, or history of surgery, presented with a unique case of a large intramuscular chondrolipoma ofthe scapula. This protruding lump over the right shoulder was present for 3 months in the patient without pain or limited range of motion. A sonographic evaluation revealed a homogeneous hypoechoic lesion in the posterior right shoulder. MRI showed that the chondrolipoma measured 7.5 x 4.6 x 3.9 cm, without remarkable bony invasion, with high signal intensity over the mass in T1- weighted images, indicating cystic changes, and mild signal enhancement within the cyst in T2-weighted images. Surgical marginal excision was performed. We identified yellowish, greasy, and firm soft tissue and two cartilaginous nodules inside the lipomatous tissue. Pathological findings revealed mature adipose tissue with a fibrous capsule and true cartilage inside. Post-operative outpatient follow-up found no recurrence after 2 years.

Conclusion: Intramuscular chondrolipoma arising from the shoulder has been rarely reported. MRI and sonography are helpful in the diagnosis.