Sarcoidosis is a chronic multi-system granulomatous disease that may commonly be revealed as a diagnosis of exclusion when compared to other common granulomatous diseases, as its pathogenesis is not well understood [1]. General clinical manifestations of sarcoidosis have protean presentations, such as fever of unknown origin, weight loss, and lymphadenopathy, followed by more organ-specific symptoms like erythema nodosum, uveitis, uveo-parotid fever, and rarely neurological and renal involvement. The pathological finding revolves around the presence of non-caseating granulomas [2].
Cardiac sarcoidosis, being more common in women, has been found in almost 10% (with occult involvement estimated at 20–25%) of patients with systemic sarcoidosis, with a larger portion of patients remaining asymptomatic [3]. Cardiac involvement can occur at any time during the natural progression of sarcoidosis, sometimes being the only manifestation, with the prognosis solely determined by the extent of involvement. 18 F-FDG PET scan is now the investigation of choice, even in the presence of an inconclusive endomyocardial biopsy, and other modalities like cardiac MRI complement the diagnosis of cardiac sarcoidosis (CS). Cardiac involvement in sarcoidosis automatically escalates the severity of the disease, invariably requiring corticosteroid therapy with added immunosuppression provided by certain biologics [4]. The extremely rare presentation of sarcoidosis as an intra-cardiac mass adds to the diagnostic dilemma and the relatively unheard-of presentation of this condition.
Case presentation
A female in her 40s presented to the emergency department with complaints of palpitations, dyspnea, and light-headedness. She had been experiencing intermittent palpitations and perceived skipped heartbeats for the preceding month, exacerbated by minimal exertion and bending over, causing discomfort. Dyspnea occurred solely during episodes of palpitations or upon exertion, with a solitary episode of light-headedness. The patient denied chest pain, syncope, or presyncope.
The patient’s family history was significant for pulmonary sarcoidosis in her father and systemic lupus erythematosus in two siblings. She did not consume alcohol or tobacco products. On examination, her general appearance was unremarkable, with a heart rate of 54 beats per minute, blood pressure of 136/88 mmHg, and no evidence of volume overload. Auscultation revealed distant consecutive cardiac sounds, with no other significant findings. Laboratory studies, including thyroid function tests, cardiac enzymes, comprehensive metabolic panel, and complete blood count, were within normal limits. The patient did not exhibit visual disturbances.
Chest radiography showed no evidence of an acute cardiopulmonary process. The initial electrocardiogram demonstrated sinus bradycardia with prominent first-degree atrioventricular (AV) block, intermittent second-degree (Mobitz type 1, 2:1 AV block), and premature supraventricular complexes. Telemetry on the following day revealed second-degree type 2 AV block (most prominent) with the lowest heart rate in the 30–40 s range (Fig. 1).
ECG and associated conduction disease progression(A to C). ECG shows very long (~ 500ms) first and intermittent Mobitz I second-degree AV block on initial presentation which eventually progresses onto complete heart block with severe bradycardia during the course in the hospital of the patient
Further cardiac workup revealed a normal echo with a 65% LVEF and a persistent 2:1 AV block on exercise stress testing.
Cardiac magnetic resonance imaging (MRI) demonstrated the presence of two distinct masses within the right atrium: one measuring 27 × 14 mm along the posterior right atrial wall just superior to the inferior vena cava junction, and another more anterior mass measuring 18 × 19 mm located inferiorly along the interatrial septum. The masses were isointense on T1 and T2 sequences and did not exhibit signal suppression on fat-saturated imaging. Homogeneous perfusion was noted within the masses, along with delayed gadolinium enhancement consistent with vascularity and necrosis (initially raising suspicion for malignancy, which was subsequently ruled out by a negative whole-body computed tomography scan) (Fig. 2). Patient was then put on a cardiac diet before being scheduled for PET-CT.
18-FDG PET-CT findings revealed several foci of abnormal metabolism in the heart in the background of patchy activity; including at the level of the atrio-caval junction, anterior to the descending thoracic aorta and caudal to the left mainstem bronchus. Additional focus in the right atrium and an additional focus in the space between the 2 atria were also found with no evidence of pleural or pericardial effusion. A more subtle focus of uptake was also noted in the left ventricular apex. The most prominent foci(2 in number) were found in the right atrium(SUV- 8.14 and 8.48 respectively) with associated low level uptake within the bilateral hilar lymph node stations(FDG avid hilar nodes)(Fig. 3).
Repeat ECG showed complete heart block with narrow escape at 33 bpm. Patient was showing progression of conduction disease for which she ended up getting a temporary pacemaker.
Bronchoscopy done in view of avid hilar LN FDG uptake was inconclusive and endobronchial lung biopsy also showed no granulomas or malignancy.
Limited Transesophageal echo done once again, a few months later, showed that there were 2 discrete, well-circumscribed, echogenic structures in the right atrium. The first structure measured 1.3 × 1.2 cm and was located in the superior aspect of the right atrium. The second structure measured 1.2 × 1.4 cm and was located in the inferior interatrial septal region (Fig. 4).
Transthoracic Echo Detecting Mass (A to F)
Patient underwent two endomyocardial biopsies, of which one was normal and the other was ICE guided. Intracardiac echocardiography (ICE) demonstrated a large, pedunculated mass arising from the membranous interventricular septum, extending superiorly and posteriorly into the interatrial septum, and then emerging in a posterior direction from the interatrial septum, covering the coronary sinus and extending to the posterior floor of the right atrium, posterior to the cavo-tricuspid isthmus. A second mass arose from the interatrial septum more superiorly, toward the superior vena cava-right atrial junction, but this was not as well-visualized on ICE compared to other imaging modalities. The latter showed presence of atypical spindle cells but was negative for cell markers, still making it difficult to rule out the possibility of angiosarcoma, hence requiring surgical removal of the mass in order to determine the basic pathology.
Intraoperative pathology demonstrated granulomas on frozen section, and the final surgical pathology revealed nodular, extensive myocardial involvement by non-necrotizing granulomatous inflammation, suggestive of sarcoid-type granulomas. Microscopic examination revealed numerous non-caseating granulomas, diffuse fibrosis, asteroid bodies, and giant cells, all consistent with sarcoidosis. These findings were not compatible with lymphoma, angiosarcoma, rheumatoid nodule, giant cell myocarditis, or a foreign body reaction (Fig. 5). Concurrently Patient’s blood sample was sent to check for levels of Angiotensin converting enzyme(ACE) which was increased(28.4) and there was increase in levels of soluble IL-12 receptor to 5844pg/ml.
Histopathological report of the mass (A–B)
TTE done post cardiac mass excision showed there were still 2 small, but prominent echogenic structures in the free wall of the right atrium though much smaller compared to previous TTE (Fig. 6).
TTE Post surgical removal of intra-cardiac masses(A–B)
Multiple malignancies like intracardiac myxoma and lymphoma were ruled out by a negative biopsy, absence of intra-cranial mets and other relevant investigations. Other rheumatological conditions that could present as intra-cardiac masses like giant cell myocarditis and rheumatoid nodule were duly ruled out by the absence of relevant family history, clinical findings and negative rheumatological work up.
Cardiac amyloidosis too can present with delayed gadolinium enhancement but was ruled out in this patient.
Angiosarcoma was ruled out only after a complete surgical resection of the mass since the biopsy of the masses did reveal atypical spindle cells, which in hindsight were benign and thought to occur due to the associated inflammation caused by sarcoidosis. Following removal of intra-cardiac masses; patient underwent removal of temporary pacemaker and insertion of a dual-chamber ICD implant to treat the complete heart block that had resulted from the progressive conduction disease due to sarcoid; with current rhythm being ventricularly paced at 60-80 bpm.
Patient was started on 30 mg methylprednisone IV daily with eventual tapering, cholecalciferol 200-400 mg for the low vitamin D levels and on outpatient started on infliximab 5 mg/kg q8h and methotrexate 7.5 mg/week. Patient was scheduled for a regular follow up of 3 months after which a TTE would be done to check for disease progression/ clinical remission.
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