LAUSR

To the Editor, persistent cervical swelling can arise from infectious diseases, malignant/benign tumors or cervical lymphedema, e.g., associated with neck surgery or impaired venous drainage [1]. Recurrent cervical swelling is even less common with only a limited number of reported cases caused by lymphatic outflow obstruction [2]. However, due to limited knowledge and imaging options, lymphatic outflow obstruction may be underdiagnosed. Nowadays, new imaging methods, especially MR lymphangiography, can provide valuable information on lymphatic anatomy and flow [3]. We report the rare case of a patient with recurrent left supraclavicular swelling associated with recurrent chylothorax. A 54-year-old woman (history: breast cancer and radiotherapy) presented at an outside hospital with recurrent painless left cervical swelling and shortness of breath. Imaging showed diffuse soft tissue edema as the cause of the clinically apparent swelling without evidence of other causes of cervical swelling (e.g., enlarged lymph nodes, tumor or venous thrombosis). Bilateral chylothorax was detected without evidence of malignancy. Under the suspicion of a lymphatic cause, the patient was referred to our institution. We performed dynamic contrast-enhanced MR lymphangiography, which revealed signs of obstructive lymphatic drainage disorder. The thoracic duct (TD) was dilated to a maximum diameter of 8 mm (normal value up to 5 mm). An additional left para-aortic lymphatic tract was visible draining into the mediastinum. Chylolymphatic reflux into left cervical and mediastinal lymphatics was observed (Fig. 1A). The terminal TD showed a segmental dilatation up to 19 mm with a contrast filling defect (Fig. 2). Subsequent sonography showed an intraluminal mass within the terminal TD as the cause of lymphatic outflow obstruction (Fig. 3A). Sonographically guided diagnostic biopsy was performed with an 18G biopsy needle to rule out a malignant cause. Histological examination confirmed the initial suspicion of a lymphatic thrombus. Post-interventionally symptoms resolved completely without recurrence of cervical swelling or chylothorax (follow-up of 21 months). On follow-up sonography, the thrombus was no longer visible (Fig. 3B). MR lymphangiography showed normalization of TD caliber and near-total resolution of chylolymphatic reflux (Fig. 1B). TD thrombosis is a very rare condition which was linked to minor trauma of the head/neck region or dysfunction of the lymphatico-venous valve [4]. Our patient underwent axillary lymphadenectomy and radiotherapy years prior to the first occurrence of neck swelling and chylothorax, which may have caused changes in the terminal TD. Visualization of the lymphatic vascular system remains challenging. Oily X-ray lymphangiography has long been the mainstay of lymphatic imaging [5], but is time-consuming, technically challenging and prone to complications. Ultrasound can be used to evaluate the terminal TD. However, it yields no information of pathological lymph flow. In recent years, MR-based imaging techniques such as dynamic contrast-enhanced MR lymphangiography (DCE-MRL) have been established to diagnose diseases of the lymphatic system. In our case, a combination of MRL and targeted sonography enabled the diagnosis of lymphatic outflow obstruction. Unfortunately, there are few & C. C. Pieper [email protected]