DISCUSSION In the outpatient clinic children presenting with a swelling in the neck are quite regularly seen with a large variety of causes. Differential diagnosis consists amongst others of arteriovenous malformations, parapharyngeal cysts, branchial cysts, thyreoglossus cysts, dermoid cysts, cavernous haemangioma, cystic hygromas, retention cysts, persistent jugular lymphatic sacs, lymphadenopathy, lymphadenitis and pharyngeal pouches. (1,2). The most important diagnostic clue in our patient was that the swelling only occurred during crying. The differential diagnosis of a swelling in the neck, which occurs during crying, is phlebectasia of the jugular vein, a laryngocele or a superior mediastinal tumour or cyst (1–3). Plain roentgenograms show mediastinal widening or air in the mass in case of a superior mediastinal tumour or laryngocele, respectively. In the case of a phlebectasia of the jugular vein, ultrasound with colour flow imaging shows a distension of the external jugular vein. (1–3). In our patient, we primarily chose to perform an ultrasound (Fig. 2) and the diagnosis phlebectasia of the external jugular vein was made. Jugular phlebectasia is defined as a fusiforme or saccular dilatation of the jugular vein without tortuosity. It is a rare condition: about 100 cases have been reported, of which 31 are children (3). Age ranges from 5 months to 68 years and it is seen more often in boys than girls (4). The right side of the neck is most commonly affected: of the 31 children the phlebectasia of the internal jugular vein was located on the right side in 23 cases, left side 5 cases and bilateral in 3 cases. This is probably caused by anatomical differences between the right and left internal jugular vein (3). Patients usually present with a soft, non-tender, nonpulsatile, saccular of fusiforme swelling in the neck, which occurs on crying, straining or when performing a Valsalva manoeuvre. Other symptoms such as a feeling of constriction, sensation of choking or discomfort during physical activity, coughing or swallowing are rare but have been described (1). Ultrasound with colour Doppler can easily confirm the diagnosis of a phlebectasia by comparing the affected and non-affected side. It shows dilatation of the vein with an increased blood flow when the child starts crying compared to normal circumstances. (1–3) Other diagnostic studies (CT, MR-angiography, venography) are only necessary when diagnosis is not clear or if surgery is indicated (1,2). The aetiology of phlebectasia is not clear. Different hypotheses have been proposed (3). Histopathological studies have shown structural changes of the venous wall in which fibrosis; loss of elastic tissue and hypertrophy of connective tissue; thinning of the venous wall and a decrease or absence of the smooth muscle layer is seen. But other studies have shown no structural abnormalities of the venous wall. Other aetiologic hypotheses that have been proposed are anomalous reduplication of the internal jugular vein (2), increased tonus of the scalenus muscle (3) and compression of the jugular vein between clavicle and the cupula of the right lung (3). Recently, a phlebectasia of the jugular vein has been reported in three patients with Menkes disease. The authors speculated that this predisposition is caused by reduced strength of the cervical fascia due to the lower activity of the copper-dependent enzyme lysyl oxidase (5). Furthermore, elevated intrathoraric pressure seemed to play a role in four children with asthma (6) and a patient on positive pressure ventilation (6). The prognosis of phlebectasia is not clear. Complications that have been described are Horners syndrome and thrombosis (3), but these are rare. Spontaneous rupture has not been described. Management is conservative. Surgical excision or endovascular sclerosis (7) is only indicated if complications or symptoms occur or for cosmetic reasons (1,3,6,7). In our patient, the swelling was first noticed after a trauma. This seems to be a coincidence rather than a cause of phlebectasia. The diagnosis was confirmed by echo Doppler. Since the swelling was asymptomatic the management was conservative.