Developmental venous anomalies (DVAs) are common abnormalities of intracranial venous drainage, which may occur in conjunction with other cerebral vascular malformations and are known for their benign natural history. The authors present the case of a 16-year-old boy who experienced a spontaneous brainstem hemorrhage due to a cavernoma. Preoperative angiography findings revealed a large DVA draining the right cerebellar hemisphere. The patient underwent suboccipital surgery for cavernoma resection and recovered completely from his neurological symptoms. Fourteen months later he returned with progressive symptoms. Repeated angiography demonstrated a complex dural arteriovenous fistula (DAVF) of the transverse sinus, which had developed next to the DVA. Several transarterial and transvenous embolizations were ineffective. Common causes of acquired DAVFs and the potential role of the DVA in the development of the DAVF in this case are discussed on the basis of the pertinent literature.