Spontaneous thrombosis of a residual arteriovenous malformation in eloquent cortex after surgery: Case report

OBJECTIVE AND IMPORTANCE: The presence of a residual arteriovenous malformation (AVM) on postoperative angiograms is typically an indication for prompt return to the operating room to complete resection, because of the risk of early hemorrhage. This approach, however, may involve risks of neurological deficits when the residual AVM is in eloquent cortex. We present a case of complete thrombosis of a residual AVM after surgery. This residual AVM tissue was located in eloquent cortex. Complete spontaneous thrombosis of residual AVMs after surgery has only rarely been reported. This phenomenon raises questions regarding the most appropriate management for residual AVMs in eloquent cortex. CLINICAL PRESENTATION: The patient was a 43-year-old, right-handed, male patient with an AVM centered in the left precentral gyrus. The patient presented with medically intractable seizures and progressive right hemiparesis. After AVM resection, angiography revealed a residual AVM with early venous drainage. Angiography performed 1 week later demonstrated a persisting AVM nidus without early venous drainage. Angiography performed 3 months later demonstrated complete thrombosis of the residual AVM. INTERVENTION: The patient has been monitored for more than 1 year, without additional symptoms or therapy. CONCLUSION: We continue to advocate prompt return to the operating room when postoperative angiography reveals a residual AVM with persistent shunting. When the residual AVM is in eloquent cortex and is small, with a single draining vein, however, observation of the patient (with strict blood pressure control) and repeat angiography after 1 week represent an alternative strategy that is supported by this case report. As this case demonstrates, it is possible for small residual AVMs to thrombose. This may avert the need for reoperation for residual AVMs in eloquent cortex, with the potential for neurological deficits.