Imaging description

Cavernous hemangioma is the lesion that most commonly contains fat (Figure 89.1); so much so that portions of some cavernous hemangiomas may be indistinguishable from a lipoma. A recurrent history of pain and swelling of the knee in children and young adults is a characteristic presentation of synovial hemangioma (Figure 89.2).

On plain radiographs the presence of phleboliths (calcified thrombi) within muscles are fairly specific of an intramuscular hemangioma. Sung et al. described a spectrum of periosteal reactions in patients with deep soft tissue hemangiomas, including lobulated solid periosteal reaction, solid continuous periosteal reaction, elliptical cortical hyperostosis, undulating periosteal reaction, and thin solid periosteal reaction. Radiographically, the differential diagnosis of reactive bone changes in soft tissue hemangiomas includes both benign and malignant bone and soft tissue neoplasm. Solid continuous periosteal reaction is the most common periosteal response associated with deep soft tissue hemangiomas. This pattern can be easily confused with a stress fracture. An associated elliptical cortical hyperostosis can simulate an osteoid osteoma but the absence of a nidus should help in the differential diagnosis. Coarsened trabecular pattern, similar to that of an intraosseous hemangioma of the spine, can be seen in association with deep soft tissue hemangiomas of the extremities.

On MRI intermediate or slightly high signal intensity on T1-weighted images and strikingly high signals on the T2-weighted images have been described in some studies. The high signal intensity on T1-weighted images corresponds to the fatty tissue in the lesion. In a recent publication Teo et al. described distinguishing features on MRI which helped in differentiating hemangiomas from malignant soft tumors. On T2-weighted images hemangiomas present with multiple lobules or tubules with high-signal intensity configuration interspaced with linear and lace-like areas. The high signals on T2-weighted images reflect the pooling of blood with cavernous spaces and slow flow within dilated venous channels.