Acquired Arteriovenous Malformation Definition: An Improper Use in Diagnostic Radiology Practice.

We read with interest the article by Dr. Rangarajan and colleagues [1] in the November–December 2007 issue of CardioVascular & Interventional Radiology regarding a case of successful endovascular treatment of uterine arteriovenousmmalformation (AVM). The diagnosis was suggested by color Doppler ultrasound (US) examination, while magnetic resonance imaging demonstrated pathological vessels within the uterine fundus at the site of the US abnormality, compatible with the diagnosis of AVM. The authors wrote that ‘‘acquired AVMs are more common than the congenital form, usually resulting from instrumentation or as a complication of malignancy, fibroids, endometriosis, or gestational trophoblastic disease.’’ AVMs or arteriovenous hemangiomas are composed of variable numbers of tortuous, dilated, thin- and thick-walled vessels of varying size, usually with at least a focal presence of an internal elastic lamina [2]. Two hundred seventy-eight cases of AVM are reported in the gynecologic and radiologic literature, without histological documentation except for the case of Chien et al. [3]. Recently, we observed a uterine AVM in a 72-year-old woman. The diagnosis of AVM was suggested by color Doppler US findings and confirmed histologically on a hysterectomy specimen. The term acquired AVM has been widely and improperly used in the radiologic literature and shoud be avoided. The term ‘‘malformation’’ implies a congenital etiology. A malformation is defined as a primary structural defect that results from a localized error of morphogenesis within the first 8 weeks following conception. More subtle defects within organs can arise at a later stage of development; remodeling during later growth of tissue which has been damaged after normal organogenesis can result in an abnormal structure by the time of birth [4]. An AVM may only be congenital and cannot be the complication of other uterine disease. Use of the term acquired AVM should be avoided when histological documentation is not available. In the radiological report the diagnosis of the lesion should be ‘‘descriptive’’ of vascular uterine abnormality. In studies of 25 embolization procedures performed in 15 patients, Ghai et al. [5] emphasize that the term ‘‘malformation’’ implies a developmental origin and that it is therefore improper to use this term in the context of acquired AVM. In conclusion, the term ‘‘arteriovenous fistula’’ or ‘‘arteriovenous shunt’’ should be used instead for acquired AVM in diagnostic radiology practice.