Hilar lymphocele following blunt trauma

Abstract

IntroductionBlunt chest trauma rarely causes thoracic duct injury. A very rare occurrence of contained mediastinal lymph collection has also been reported [1]. To our knowledge, a hilar lymphocele following a blunt trauma has not been reported. We present such a case. Case reportA 34-year-old male patient presented with a complaint of coughing. He had had a motor vehicle accident 2 months prior in which a truck crashed into the back of the car and the victim struck his chest against the dashboard. He did not have any reported injury. His chest X-ray showed a well-defined mass in the right hilum ( Fig. 1). His last chest X-ray, taken 8 years previously, had been normal (Fig. 2). Thoracic CT examination showed a 3-cm mass with well-defined margin (Fig. 3). The density of the mass was fluid-like (20 HU) and showed no contrast enhancement. On MRI examination the mass had low signal intensity (SI) on T1-weighted and high SI on T2-weighted images (Fig. 4). The mass was homogeneous and showed SI similar to cerebrospinal fluid on all MRI sequences. He underwent CT-guided 22-G fine-needle aspiration biopsy in which 13 ml of slightly turbid yellowish fluid was aspirated, and the lesion nearly disappeared on chest X-ray. The fluid was rich in lymphocytes. The cell count revealed 93 % lymphocytes, 6 % neutrophils and 1 % red blood cells under microscopic examination, and biochemical analysis showed 0.9 g/dl of protein and 130 mg/dl triglyceride content. Control X-ray examination 2 days after the procedure showed refilling of the lesion (Fig. 5). T1-weighted MRI examination after a fatty meal did not show any change in SI of the lesion. Follow-up chest Xray and MRI in the first year showed no change in the size and shape of the lesion.The hilar lesion was rich in lymphocytes without malignant or inflammatory cells and showed a fast refilling after aspiration, suggesting a hilar lymphocele which had a narrow connection with the thoracic duct. DiscussionLymphatic system injury of the thorax is most commonly seen in penetrating trauma. Blunt chest trauma rarely causes thoracic duct injury resulting in chylothorax, and a very rare occurrence of contained lymph collection has also been reported [2±4]. On plain chest X-rays these lymphoceles are seen as mediastinal widening or focal masses [1±4]. These masses may develop immediately or several months after injury [1±3]. To our knowledge, lymphocele in the hilum due to blunt trauma has not been reported. There are similar reported cases in various locations. Two of these cases presented in anterior mediastinal location [4,5], two in posterior mediastinal location [2,6], one in the supraclavicular region [3], one adjacent to the trachea [7], one subcutaneous in the chest wall [8] and one over the hilum [9].The CT and MR characteristics of our case suggested a lesion with high water content which could be a congenital cyst or infiltrated lymph node by tuberculosis, sarcoidosis or lymphoma. Although in our case the chest X-ray taken 8 years previously excluded a congenital cyst, an enl...

Imaging of Cystic and Cyst-like Lesions of the Mediastinum with Pathologic Correlation

“…They are not commonly found in the mediastinum. [3738] Most lymphoceles, also known as chylous pseudocyst, cystic lymphangiomas, and lymphatic duct hygroma are usually solitary and well-circumscribed mass. On a chest radiograph, lymphocele appears as a smooth focal mediastinal mass or mediastinal widening.…”