Abstract 14723: A Rare Case of Constrictive Pericarditis: Inflammatory Myofibroblastic Tumor

Abstract

Case Presentation: A 14-year-old female presented with a 3-week history of lower extremity edema, abdominal distension, fatigue, and dyspnea on exertion. Her examination was notable for an elevated jugular venous pulse, abdominal distension with hepatomegaly, and 2+ pitting edema in the bilateral lower extremities. Laboratory findings were within normal limits. EKG showed low-amplitude QRS and echocardiogram confirmed bi-atrial enlargement, a dilated and non-compressible IVC, dyskinetic interventricular septum, and elevated right atrial pressures. Chest computed tomography demonstrated mediastinal mass with findings of a 6.2 x 4-centimeter mass in the pre-vascular space, diffuse necrotic mediastinal lymphadenopathy, and constrictive pericarditis with associated congestive hepatopathy. Cardiac magnetic resonance imaging revealed significant enhancement in T2 STIR with severe circumferential delayed enhancement, diastolic bounce, and respirophasic shift. A right heart catheterization was pursued which revealed elevated filling pressures but preserved cardiac index. The patient underwent video-assisted thoracoscopic biopsy of the mass with an initial histologic diagnosis of inflammatory myofibroblastic tumor (IMT). She underwent radical pericardiectomy for symptom resolution. Discussion: IMT is composed of spindle cells mixed with infiltrates of varying numbers of inflammatory cells. Although IMT can present in any age group, most patients who develop IMT are in adolescence. IMT is incredibly rare and its etiology still remains unclear. It remains difficult to distinguish IMT from a malignant tumor on the basis of imaging. As a result, in most cases, a definitive diagnosis is made based on the histopathological findings from either a resected tumor or a needle biopsy. Management of IMTs presents a challenge as treatment protocols have not clearly been established; radical local excision of the tumor is the mainstay of treatment.