Vascular malformations in the uterus: ultrasonographic diagnosis and conservative management

Abstract

Objective: To investigate the presence and outcome of uterine vascular malformations in women with abnormal premenopausal bleeding. Study design: In this observational study 265 consecutive patients with abnormal premenopausal bleeding were examined by the same ultrasonographer with transvaginal gray-scale ultrasonography and color Doppler imaging. A final diagnosis of uterine vascular malformation was based on ultrasonographic findings, hysteroscopy or histological findings. Patients suspected of uterine vascular malformations at ultrasonography were closely monitored. Results: In nine patients (3.4%) we found ultrasonographic features of uterine vascular malformations. Color Doppler imaging showed hypervascularity, marked turbulence, and low-impedance, high-velocity flow. In six patients the condition resolved spontaneously. Two patients with hydatiform mole needed chemotherapy and their condition normalized. One patient underwent a selective embolization of the uterine artery. Subsequently, five patients had uncomplicated pregnancies after resolution of the vascular malformation. Conclusion: Uterine vascular malformations are more common than previously thought. We conclude that conservative management is a valuable option in many of the acquired pregnancy-related cases that are diagnosed with color Doppler imaging.

Introduction

Uterine arteriovenous malformations (AVM) are considered to be rare entities, with in 1997 only 73 cases reported in the literature [1]. However, the true incidence of AVM is unknown. These lesions may be congenital or acquired [2], [3]. Congenital AVM result from a failure in the embryological vascular differentiation [4], leading to multiple vascular connections. AVM are isolated anomalies in otherwise healthy persons [2]. They are extremely variable in size and anatomical location, leading to different clinical presentations. AVM have been reported in head, neck, extremities, but also in bowel, lung, spleen, stomach, pancreas, bladder, uterus or vagina [3], [5]. Congenital uterine AVM tend to invest the surrounding tissues, and constitute a very difficult therapeutical challenge. If asymptomatic no treatment is required. Since proliferation during pregnancy has been reported [2], [6], some authors consider it an absolute contraindication for pregnancy [2]. Most cases, however, are acquired and have resulted from previous uterine surgery or curettage, gestational trophoblast disease, exposure to diethylstilbestrol, infection, endometrial or cervical cancer [7], [8], [9], [10], [11], [12], [13].

Historically the diagnosis of uterine AVM was made only at laparotomy or upon pathological examination of the uterine specimen after hysterectomy had been performed. Subsequently, angiography became the gold standard for diagnosis of this condition [14]. More recently, color Doppler ultrasonography [15], [16] and hysteroscopy [3], [14], [17] have been proposed for obtaining a reliable diagnosis. More recent reports [5], [13], [15], [16], [18] suggest that color Doppler ultrasonography is the preferred method of diagnosing AVM, and that angiography should be reserved for cases in which surgical intervention and therapeutic embolization of the lesion are planned [15]. The ultrasonographic diagnosis of AVM is based on the presence of hypoechoic tortuous spaces in the myometrium demonstrating vascular flow as evidenced by color Doppler [1]. Spectral analysis of the vessels shows low impedance, and high velocity flow. To date it is not known how specific these criteria are to detect true uterine AVM.

Most reported cases so far have been treated with either hysterectomy [2], [3], [7], [13], [14], [15] or embolization of the uterine arteries [12], [20], [21], [22], [23], [24]. Using the published ultrasonographic criteria of AVM, we were surprised by the number of cases of uterine vascular malformations that had been diagnosed in the department of Obstetrics and Gynecology of our institution. We therefore have undertaken present observational study. The aims of the present study were, first, to estimate the proportion of premenopausal women with abnormal vaginal bleeding in whom uterine AVM or vascular malformation was considered to be the cause of abnormal bleeding; second, to analyze the outcome of patients diagnosed with uterine AVM at color Doppler imaging.