Haemangiomas around the knee mimicking medial meniscal tears. Report of two cases and review of the literature

There are few reports in the English literature of extra-articular lesions simulating intra-articular pathology of the knee. Two cases of histologically confirmed haemangiomas related to the distal femur, presenting with knee pain suggestive of medial meniscal damage, are reported. A 27-year-old woman presented with persistent anteromedial right knee pain despite having undergone two arthroscopies for medial meniscal damage. An MRI showed a soft tissue mass on the medial side of the distal femoral metaphysis. The symptoms resolved only after open resection of the lesion. Histology showed a periosteal haemangioma. The second patient, a 24-year-old woman, complained of posteromedial left knee pain for 3 months. Although a medial meniscal tear was suspected, an MRI showed a soft tissue mass close to the bone of the distal femoral diaphysis. The symptoms resolved after open resection of the lesion. Histology showed a soft tissue haemangioma. Both patients were asymptomatic with normal MRI scans 6 to 12 months postoperatively. Although meniscal tears can present in young patients without a history of trauma, an MRI is extremely useful in diagnosing other lesions causing similar symptoms. Haemangiomas around the knee are rare, in particular periosteal haemangiomas of the distal femur as no report has been found in the English literature.