Presentation
Painless left facial swelling.
Patient Data
Well-defined intramuscular mass within the left masseter, isointense to muscle on T1, hyperintense on T2 with no restricted diffusion (high signal ADC), composed of numerous serpiginous signal voids which are felt to represent vascular structures. The post-contrast dynamic sequences show progressive enhancement with almost fill-in on delayed sequences.
Case Discussion
MRI features most consistent with soft tissue venous malformation, commonly known as soft tissue hemangiomas.
According to newer nomenclature (ISSVA classification of vascular anomalies), these lesions are referred to as slow-flow venous malformations.