Photograph of the boy, then 7 years old, with slowly progressive, clearly painful swelling laterally at the level of the right knee joint. A distinct pulsation is felt on palpation. Genetically confirmed PTEN hamartoma syndrome.
Digital subtraction angiography (DSA) of the knee (left AP projection, left lateral projection) shows an AVM with a rather spherical, aneurysmal nidus as well as another nidus intraosseously in the lateral tibial plateau. This very spherical, aneurysmal nidus together with the painful, progressive mass is suggestive of a PTEN hamartoma.
After successful embolization of the two AVM nidus parts, the radiographic overview images (left AP, right lateral projection) shows a complete cast specimen of the two portions caused by the embolic agent, the so-called cast. This consists of ethylene-vinyl alcohol copolymer, which contains radiopaque tantalum.
The repeat DSA 4 months after the previous embolization (left AP, right lateral) shows an early, circumscribed recurrence. Especially in the case of AVMs associated with a PTEN hamartoma syndrome, patients must attend for follow-up at short intervals, as these AVMs in particular have a high tendency to recur.
PTEN hamartoma syndrome is often diagnosed after a delay. Multiple arteriovenous malformations (AVM), which angiographically appear to include a spherical aneurysm, and a clear accompanying painful soft tissue lesion are often indicative. If this is accompanied by dilated head circumference, a PTEN mutation may be the reason. Early recurrence is common after embolization of these AVMs, and resection of the occluded nidus should be attempted whenever technically possible. This was also the plan in this patient. The recurrence occurred early after the first, angiographically complete embolization. After repeat embolization, the extraosseous portion of the nidus was then successfully resected. The intraosseous portion in the tibia shows no recurrence at follow-up to date.
All images © Wohlgemuth