Fig. 1

Fig. 1

Three patients with somatic RIT1 variants identified in AVM tissue. a Patient P1 displays a capillary malformation and swelling of the right side of the face. b MRI of P1 at the age of 4 months, the image of a transversal T2 TSE sequence, in which an AVM could be detected; the extent of the lesion is labelled with red dashed line indicating soft tissue edema and flow-voids. c The MR angiography shows increased perfusion on the right side of the face (left side within the panel). d Patient P2 shows a prominent mass of the left cervical/nuchal area. e MR imaging (coronal T2 sequence with fat saturation), which shows the hyperintense isolated intramuscular lesion, flow-voids seen within the lesion representing high AVM flow, and disfiguring overgrowth. f MR angiography, which shows the large AVM connected to the subclavian and the thyrocervical trunk with multi-chambered central nidus. g Clinical aspect of the Patient P3 with swelling on the left forearm, close to the medial side of the elbow. h T2W sagittal images demonstrating a well-defined fusiform shaped hyperintense lesion involving the flexor muscle (pronator teres) of the forearm. Flow voids (red dashed line) are seen within the lesion representing arterial blood vessels. MRI Magnetic Resonance Imaging