Primary cardiac diffuse large B-cell lymphoma, non-germinal centre B-cell type in an immunocompetent woman

Abstract

Primary cardiac lymphomas are extremely rare and always occur in immunodeficient persons. Here, we report a very rare case of a primary cardiac diffuse large B-cell lymphoma in an immunocompetent 41-year old woman. Echocardiography and computed tomography revealed a mass measuring 74 mm × 49 mm in the right atrium. No tumour formations were recognized in other organs. Laboratory data did not reveal immunosuppression, and the human immunodeficiency virus was negative. Histological and immunohistochemical studies showed that the cardiac tumour was diffuse large B-cell lymphoma, non-germinal centre B-cell type. Epstein–Barr Virus-encoded small RNA was negative by in situ hybridization. The patient died 6 months after the operation.

INTRODUCTION

Primary cardiac lymphomas (PCLs) are extremely rare, accounting for only 2% of primary heart tumours and 0.5% of extranodal lymphomas [1]. PCL always occurs in immunodeficient persons [2]. Herein, we report a very rare case of a primary cardiac diffuse large B-cell lymphoma, non-germinal centre B-cell type in an immunocompetent patient.

CASE REPORT

A 41-year old woman presented with face, neck, right upper limb and right supraclavicular fossa swelling, chest discomfort and generalized fatigue for 2 months. No palpable lymph nodes, liver or spleen were observed. A complete blood picture showed normal. She had normal liver and renal function. Tests for Hepatitis B Virus Surface Antigen (HBsAg), anti-Hepatitis C Virus (HCV) and anti-HIV were negative. Echocardiography revealed a mass arising from the free wall of the right atrium and extending to the opening of the right atrioventricular valves. Chest computed tomography (CT) revealed a low density mass measuring 74 mm × 49 mm (Fig. 1A) in the right atrium and partly extending to the right ventricle. No tumour formations were recognized in other organs. The patient was suspected of cardiac myxoma by echocardiography and CT, and referred to the Department of Cardiac Surgery. The operation was performed via a standard median sternotomy under general anaesthesia. The cannula was inserted into the ascending aorta, superior vena cava, and inferior vena cava and the venous return was through a bicaval cannulation. The tumour was firm, 10 cm × 8 cm × 6 cm in size, attaching to the right atrium and extending to the right ventricle of the heart. The tumour had no clear margin and was resected incompletely in case of impairing the wall of the right atrium. The patient's symptoms were relieved after the operation.

Figure 1:

(A) A CT scan revealed the heterogeneity of soft tissue density located within the enlarged right atrium. (B) The gross of specimen showed cardiac mass measuring 65 mm × 45 mm × 30 mm was nodular, homogeneous and fish-flesh-like on cut surface. (C) A histological examination showed diffuse a infiltrate of large lymphoid cells with oval to irregular nuclei, vesicular chromatin and high mitotic activity were noted (H&E stain, ×400); (D) The large lymphoid cells showed strong, diffuse and membranous expression of CD20, immunohistochemistry staining ×400; (E) tumour cells were positive for bcl-2. Immunohistochemistry staining ×200; (F) high Ki-67 expression in tumour cells. Immunohistochemistry staining ×200.

Macroscopically, the surgical specimen measured 65 mm × 45 mm × 30 mm and the cut surface of the tumour was soft, homogeneous and fish-flesh-like in appearance (Fig. 1B).

Microscopical examination revealed that the tumour had no clear margin and a diffuse infiltrate of large lymphoid cells with oval to irregular nuclei, vesicular chromatin and high mitotic activity were noted (Fig. 1). Immunohistochemical staining showed the tumour cells were positive for CD20, CD79α, vimentin, bcl-2, lambda-chain and negative for CD45RO, CD3, bcl-6, CD10, chromogranin-A, neurone-specific enolase, synaptophysin, CD56, CD30, CD38, CD138, CD99, myoD1, myogenin, kappa-chain, anasplastic lymphoma kinase, CK and S-100 protein. Approximately 90% of the tumour cells showed Ki-67 expression (Fig. 1). Furthermore, tumour cells were negative for Epstein–Barr Virus-encoded small RNA using in situ hybridization. These findings led to the diagnosis of a primary cardiac diffuse large B-cell lymphoma, non-germinal centre B-cell type based on 2008 World Health Organization diagnostic criteria. The patient refused further chemotherapy and died 6 months after the operation.

DISCUSSION

PCL refers to the lymphoma involving only the heart and/or the pericardium. Cairns et al. [3] suggested that PCL could also present elsewhere as small secondary lesions, with the vast bulk of the tumour arising in the heart. According to the generally acknowledged criteria for primary lymphoma in soft tissue [4], we suggest that PCL should meet the following criteria: (i) the tumour occurs in the heart, particularly, the bulk of the tumour is intrapericardial; (ii) the patient has no previous history of lymphoma; (iii) lymphoma is not found in more than two locations including the lymph nodes or extranodal organs; (iv) cases should be excluded if the tumour occurs in sites with abundant lymphoid tissue, such as skin, bone, axilla, groin, scalp, face and retroperitoneum and (v) lymph node structure should not be observed in the biopsy specimen.

PCL was mostly reported as arising in the right atrium and right ventricle of the heart [5], which may disturb the tricuspid valves and cause heart failure and obstruction. The most common presentation of PCL is arrhythmia, followed by pericardial effusion with tamponade, dyspnoea and cardiac failure. Unusual presentations including superior vena cava syndrome, embolic stroke or symptoms suggestive of gastrointestinal disease may occur.

Histologically, the majority of PCL are diffuse large B-cell lymphoma, although rare cases of T-cell, anaplastic and plasmablastic lymphomas have also been described [6]. PCL occurs more frequently in immunocompromised patients, such as in patients with AIDS, in subjects taking immunosupressive drugs, and in cardiac transplantation recipients. However, this reported case had normal immune status.

Complete PCL resection by surgery is very difficult. The main regimen for chemotherapy has been CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) [7]. The prognosis of patients with PCL is poor. The patient in our case refused further chemotherapy and died 6 months after the operation.

Conflict of interest: None declared.