De novo development of a lesion with the appearance of a cavernous malformation adjacent to an existing developmental venous anomaly.

A case is presented in which a complex multicystic hemosiderin-containing lesion developed adjacent to a previously documented developmental venous anomaly (venous angioma). This lesion had the characteristic MR imaging appearance of a cavernous malformation. Follow-up MR imaging demonstrated a decrease in both the size and complexity of this lesion, which suggests at least a portion of the lesion was due to sequelae of hemorrhage. This case further supports the association of a de novo, hemosiderin-containing lesion in association with developmental venous anomaly. Implications of these findings are that the commonly seen "cavernous malformations" in association with developmental venous anomaly are acquired lesions, and not congenital in origin. A review of the literature discussing the etiology of cavernous malformations and their reported association with the developmental venous anomaly is provided.