Intramuscular Cavernous Hemangioma of the Vastus Intermedius Muscle with Knee Joint Extension: A Case Report

Intramuscular Hemangiomas (IHs) are benign vascular neoplasms usually arising within the striated muscle of the trunk and extremities. These account for less than 1% of all hemangiomas. IH in the distal thigh with extension to knee joint is rarely reported, and may be confused with other lesions. A case of cavernous intramuscular hemangioma that involved distal third of left thigh with extension to knee joint in a 10-year-old girl is reported in this paper. The girl initially presented with sclerotic bony changes in imaging and slow growth during 4 years which at firt was misdiagnosed as osteoid osteoma for a long time. The patient’s parents refused the recommended biopsy of the lesion. Four years later, after the onset of the patient’s complaints of pain and swelling in the distal thigh, another survey with Doppler ultrasound and MRI was done. The tumor was finally diagnosed as hemangioma, and was completely resected. Histopathology confirmed a cavernous hemangioma with free margins. Our case was both an educational and clinical case with radiological presentations like articular involvement of this extra articular hemangioma and there was delay in diagnosis.