Brachial Plexopathy and Cardiac Tamponade: An Uncommon Presentation of Diffuse Large B-Cell Mediastinal Lymphoma

Abstract

INTRODUCTION: Primary mediastinal large B-cell lymphoma (PMLBCL) is a unique type of B-cell lymphoma probably arising from a putative thymic medulla B-cell. PMLBCL comprises seven percent of diffuse large B cell lymphomas (2.4 percent of all non-Hodgkin lymphomas). There is a female predominance and a median age at diagnosis in the third to fourth decade. In some cases, the presentation can be an oncological emergency with locally invasive anterior mediastinal mass arising from thymus causing external pressure on the heart and the surrounding structures. PMLBCL presenting as brachial plexopathy with cardiac tamponade is an uncommon presentation.CASE PRESENTATION: 37-year-old female, who presented to the ED with a 3-week history of left-sided neck pain and progressive swelling with associated 2 weeks history of numbness in the left wrist, tingling sensation in her 4th and 5th finger with weakness on the same side. She endorsed exertional dyspnea and palpitation that worsened over the last 4 days prior to presentation.On examination she was noted to have left sided neck mass about 6 x 8cm, firm, nontender, non-mobile with extension below the clavicle. Tachycardic with Muffled heart sounds and grade 3/6 Systolic Ejection Murmur at right upper sternal border. Flexion deformity with reduced sensation of the left 4th and 5th finger. Chest X-ray shows cardiomegaly with widened mediastinum. Computed Tomography scan was suggestive of anterior mediastinal mass. Echocardiogram done showed large pericardial effusion with Echocardiographic findings consistent with tamponade physiology.She underwent pericardiocentesis with 700 cc of serosanguinous fluid drained and subsequently had CT guided biopsy of the anterior mediastinal mass. Biopsy report showed high grade B-cell lymphoma with Immunostain showing lymphoma cells positive for CD20, BCL6 and negative for BCL2, CD5. She was diagnosed to be High grade stage IIB, commenced on chemotherapy and completed 6 cycles of DA-EPOCH-R.Left hand weakness and neuropathy resolved following chemotherapy. Repeat CT chest and Echocardiogram showed near resolution of the anterior mediastinal mass and pericardial effusion respectively. DISCUSSION: The majority of patients with primary diffuse large B-cell mediastinal lymphoma are symptomaticat the time of diagnosis. Patients present with a locally invasive anterior mediastinal massoriginating in the thymus, with frequent airway compromise and superior vena cava (SVC)syndrome. Symptoms related to the compression or invasion of local structures (i.e., cough, dyspnea, dysphagia, hoarseness) are common, systemic B-symptoms occurs in about 47% ofpatients, brachial plexopathy is an uncommon presentation.CONCLUSIONS: PMBL is a tumor of young adults who present with a rapidly proliferating tumor. At diagnosis, the tumor is usually limited to the mediastinum, therefore high index of suspicion is required in making the diagnosis.