Abstract
BACKGROUND: Chondroma is a slowly growing, benign cartilaginous tumor which predominantly occurs in long bones of the hands and feet. Primary mediastinal chondroma is rare, especially with Horner's syndrome. CASE PRESENTATION: We reported the case of a 31-year-old woman with a posterior mediastinum mass associated with Horner's syndrome. After complete dissection of the mass, a pathological diagnosis of the primary mediastinal chondroma was rendered. The patient has shown no local recurrence or distal disease in a 3.5-year follow-up period. CONCLUSIONS: The preoperative diagnosis of chondroma should combine various examinations for comprehensive evaluation. Complete surgical resection should be the first choice of the treatment due to the risk of malignancy.