A 20-year-old Saudi male, presented to the emergency room (ER) in December 2013, with a slowly growing epigastric, painless swelling for one month. It was found to be associated with infrequent self-limiting palpitations. Otherwise, he was asymptomatic. Physical examination was unrevealing, other than a mild tenderness over the swelling, along with fluctuation.
This investigation was within normal limits, including complete blood count, renal and liver function tests, and electrolytes, along with an erythrocyte sedimentation rate of 20 mm/h, C-reactive protein of 12.7 mg/L, plus a negative human immunodeficiency (HIV) virus screening. His electrocardiogram (ECG) showed sinus tachycardia with right axis deviation, non-specific T-wave abnormalities in the inferior leads and non-specific QRS changes in the chest leads (Fig. 1). Initial ER bedside abdominal ultrasound confirmed the presence of a collection in the anterior abdominal wall. A plain chest X-ray showed a small loculated right pleural effusion, attached to the right heart border (Fig. 2). Abdominal and chest computed tomography (CT) revealed a multi-located mediastinal and pleural collections involving the pericardium, penetrating the diaphragm wall, causing another sub-diaphragmatic and an abdominal wall collection without evidence of parenchymal lung disease.
Transthoracic echocardiography (TTE) was done to more precisely assess pericardial effusion, ultimately revealing a large homogenous mass in the right atrium, obstructing the right ventricular inflow (Fig. 3); there were no signs of pericardial disease, given preserved systolic function and no valvular disease.
Cardiac magnetic resonance (CMR) showed a large homogenous mass, measuring 25 x 48 mm along the lateral, inferior and inferomedial walls of the right atrium with a homogenous signal demonstrating a significant obstruction (Fig. 4, Panels A-C). The T2-weighted signal did not suggest fatty content of the mass or fibrosis in delayed enhancement images. There was another mass with the same signal intensity along the inferior wall of the left ventricle, engulfing the inferior vena cava, without any sign of obstruction.
Positron emission tomography scan was done, showing multiple soft tissue densities with hypermetabolic activity in the anterior mediastinum, in the right pericardial region, the right supra-diaphragmatic area extending to the midline and in the perivascular region. A hypermetabolic soft tissue density extending from the subcutaneous tissue into the anterior abdominal wall muscles, was also seen. Otherwise, there was physiological uptake in the brain, liver, spleen, gastrointestinal, and genitourinary tracts.
A purulent fluid was drained from the anterior abdominal wall collection. While awaiting culture results, we took a biopsy from the abdominal collection wall, showing caseating granuloma (Fig. 5). Initially, all cultures andacid-fast bacilli (AFB) smears were negative, but three weeks later, mycobacterial culture grew a pansensitive mycobacterium tuberculosis (MTB), confirming the initially suspected diagnosis. MTB-polymerase chain reaction (PCR) from the collection was positive.
A multidisciplinary decision deferred cardiac biopsy or surgery to start first-line anti-TB treatment (ATT) (isoniazid, rifampicin, pyrazinamide and ethambutol), including steroids (prednisolone) to avoid possible paradoxical increase of the mass after initiation of ATT and anticoagulation to preclude thrombus formation andpossible thromboembolism. He was discharged on an enoxaparin subcutaneous injection, which was changed after three months to warfarin, due to compliance issues.
After five months, a repeated TTE and CMR showed regression of the mass to less than 10% of its original size (Fig. 4, Panels D-F). He continued treatment for a total of 12 months. A repeated CMR at four years showed a near-complete resolution of the mass (Fig. 6).