But I Thought Itʼs a Safe Technique? An Infection of a Solid Mediastinal Mass After Endoscopic Ultrasound (EUS)-Guided Fine Needle Aspiration (FNA)

Abstract

Introduction: There is a known high risk of infection during EUS guided FNA of mediastinal cysts. Here we present a case of an apparent solid mediastinal lesion that in retrospect was an unrecognized solid bronchogenic or duplication cyst. Case description: A 47 year old female with a medical history of hypertension, hypothyroidism and hyperlipidemia presented to her doctor's office with epigastric pain. Labs showed a normal complete blood count, liver enzymes and serum lipase. Abdominal sonography was normal. Given the persistence of pain, a contrast abdominal CT scan was done and revealed a lobulated homogeneous mass within the distal esophagus that measured 3.1x 5.3x 5.2 cm. Esophagogastroduodenoscopy (EGD) was completed and revealed gastritis with no esophageal lesion. EUS was performed and showed a 5cm long extraluminal paraesophageal mass at the distal esophagus extrinsic to the esophageal wall. The mass was well circumscribed, isoechoic, and was sampled with 5 passes of a 22 gauge needle under doppler guidance. The samples were mucoid and white in consistency. Histopathology revealed thick proteinaceous debris with an occasional macrophages. Two days after the FNA the patient developed chest pain with fever and elevated white blood count on labs. CT scan of the chest showed an increase in the size of the distal esophageal mass, now measuring 5.2 x 6.1 x 4.6 cm. Imaging findings along with fever and leukocytosis suggested infection of the lesion. The patient was admitted to the hospital and started on IV antibiotics. Her symptoms resolved and she was discharged home on a prolonged course of IV and oral antibiotics. Four weeks later, a repeat CT scan of the chest showed interval decrease in size and density of distal esophageal mass. Discussion: EUS is useful in distinguishing cystic and solid lesions in the mediastinum. EUS guided FNA of solid mediastinal lesions is considered to be a safe technique. However, FNA can lead to mediastinal cyst infection with associated complications despite pre and post-procedural antibiotics up to an infection rate as high as 14%. Infected duplication cysts must be treated with antibiotics. Thoracotomy with cyst resection must be considered in cases where infection persists despite antibiotic treatment. This case report highlights the caution that must be exercised in sampling all mediastinal lesions since cystic lesions may appear solid if filled with debris, predisposing to a high risk of infection.