The radiological manifestations of intramuscular haemangiomas in adults: magnetic resonance imaging, computed tomography and ultrasound appearances.

OBJECTIVE: Intramuscular haemangiomas in adults may appear similar to soft tissue sarcomas on imaging. This study evaluates the imaging characteristics of intramuscular haemangiomas on magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound.

SUBJECTS AND METHODS: Retrospective review of medical records, imaging and pathology details of 34 patients presenting with intramuscular haemangiomas was performed. Age of patient, size, site of lesion and type of imaging was recorded. Lesions were evaluated for calcification, presence of fat, outline, texture, vascularity, enhancement and involvement of local structures.

RESULTS: There were 12 male and 22 female patients aged between 9 years and 90 years (mean 39 years). Twenty-two lesions involved muscles of the extremities and 12 involved muscles of the trunk. Mean duration of the lesions was long: 59.3 months (range 3-240 months), with an average size of 7.5 cm (1.5-15 cm). Imaging comprised 27 MR studies, seven CT scans, 19 ultrasounds, and eight plain films. All lesions were well defined, lobulated and heterogeneous. None showed local invasion. On MRI and CT, 93-100% showed the presence of fat and 100% showed vascular channels and enhancement on MRI, CT and ultrasound. Phleboliths were seen on four plain films (50%) and on the corresponding MR images. On MRI, 70% of lesions had mildly hyperintense signal on T1-weighted sequences and 96% had hyperintense signal on T2-weighted sequences (relative to skeletal muscle). Histopathology confirmed diagnosis in all cases, showing the presence of fat, medium/large vessels and skeletal muscle.

CONCLUSION: Intramuscular haemangiomas have characteristic appearances on MRI, CT and ultrasound. Long history, presence of fat, calcification and internal vessels should alert the radiologist to this diagnosis prior to biopsy.