Extraskeletal osteochondroma near the hip: a pediatric case.

Extraskeletal osteochondroma near the hip is rare and its pathological diagnosis is based on radiological and histopathological examination. It is vital that such a diagnosis be considered when a discrete, ossified mass is localized in soft tissues, even at atypical sites. Differential diagnoses include myositis ossificans, a lipomatous lesion, a pseudomalignant osseous tumour, an ossifying fibromyxoid tumour, an extraskeletal chondroma with endochondral ossification, synovial (osteo) chondromatosis, tumoural calcinosis, a synovial sarcoma and an extraskeletal osteosarcoma. Clinical awareness of this benign entity is important as no malignant transformation or metastasis has been reported. Marginal excision with histopathological identification is the treatment of choice.