Atsuko Ueyama, Y. Wada, Masahiro Yamamoto
Jul 3, 2020
A 14-day-old term-born, male infant was brought to our outpatient unit because of persistent umbilical discharge. Umbilical examination revealed a trapezoidal, firm granuloma of 20 mm diameter and a small projection on the top (Fig. 1a). This was an unusual presentation that differed from a common umbilical granuloma. Abdominal Doppler ultrasonography revealed the presence of an umbilical arteriovenous (AV) communication. The superior and inferior epigastric arteries connected to each of the umbilical arteries and merged with the umbilical vein (Fig. 1b and c). No other AV communication was observed on ultrasound of the whole body. Based on these findings, an AV malformation (AVM) was suspected. We considered performing computed tomography (CT), weighing the risk of radiation exposure against the benefit of further evaluation. We decided not to perform CT; the ultrasound study provided sufficient information for the surgery. Excision of the AV communication and reconstruction of the umbilicus were performed when the infant was 25 days old (Fig. 1d). The pathology report confirmed the absence of a nidus formation in the AV anastomosis. Therefore, we diagnosed the communication as an AV fistula (AVF), implying that it was acquired postnatally. The postoperative course was uneventful and the patient was discharged on postoperative day 1. Umbilical AV communications are extremely rare and few cases have been reported. The terms AVM and AVF have been used interchangeably in the literature; however, the two entities need to be distinguished based on the pathology findings. In contrast to AVF, AVM exhibits a nidus formation as a congenital vascular anomaly. Umbilical AVF with pathological findings has rarely been reported; almost all patients with this condition had undergone prior placement of a catheter in the umbilical vessel. Therefore, to our knowledge, this is the first case report in the English literature of an umbilical AVF in a healthy neonate, without prior intervention on the umbilicus. In the present case, the anastomosis of the epigastric and umbilical arteries is attributed to AVF formation. The epigastric artery provided extra blood flow to the umbilical artery. This may have interfered with the spontaneous closure of the umbilical arteries, promoting vascularization from the artery into the vein. In addition, placental hormones, human chorionic gonadotropin (hCG), and estrogen, may have promoted the formation of these structures. In cases of acquired uterine AV communications, it is proposed that the effect of hCG and estrogen on the insulted uterine blood vessels plays a role. This inference can be applied in the present case. The histological study of the surrounding tissue was pyogenic. One may hypothesize that umbilical inflammation independently caused AVF. Generally speaking, if this were true, the occurrence of AVF in umbilical granuloma would be more common. Therefore, in the present case, we considered the inflammation was a co-occurring condition with AVF. A patient with AV communications may be asymptomatic or have life-threatening hemorrhage and heart failure, depending on the magnitude of the blood-flow shunting and bleeding. Therefore, early diagnosis is crucial to prevent complications. Ultrasound is a useful modality in this setting. In the present case, the ultrasound was sufficient for ruling out the existence of other AV communications in the whole body and for ensuring surgical safety, as in the previous report. Contrast-enhanced CT has also been used to obtain the whole picture of this type of lesion; however, the risk of radiation exposure and the possible need for sedation (to avoid movement) are concerns as these are often hazardous in neonates. If enough ultrasoundbased information is obtained, the indication for CT should be based on the severity of the case and the patient’s condition When presented with an umbilical granuloma with an unusual appearance, clinicians should consider an AVF in the differential diagnosis, even without prior umbilical intervention. In such cases, whole-body ultrasound imaging is recommended for the detection of other underlying vascular anomalies.