Primary mediastinal large B cell lymphoma in a woman who is human immunodeficiency virus positive presenting with superior vena cava syndrome: a case report

BACKGROUND: The risk of non-Hodgkin lymphoma is increased 200-fold in individuals seropositive for human immunodeficiency virus compared to those free from human immunodeficiency virus. Human immunodeficiency virus-associated non-Hodgkin lymphoma is known for its atypical presentation, aggressive ability, widespread involvement, poor response to chemotherapy, and high relapse potential which makes both the diagnosis and management a difficult undertaking especially in resource-poor settings. CASE PRESENTATION: We report a case of primary mediastinal large B cell lymphoma in a 46-year-old woman of African descent who is human immunodeficiency virus positive who presented with symptoms of superior vena cava syndrome. Her past medical history was remarkable for a 23-year history of systemic hypertension and a 10-year history of human immunodeficiency virus infection. A physical examination revealed an underweight woman with right-sided facial, neck, upper limb, and trunk swelling together with distended veins on her chest and abdomen draining downwards. A respiratory examination revealed a reduced chest expansion, stony dull percussion note, and absent breath sounds on her entire right side with a left-sided tracheal deviation. She had a CD4 count of 146 cells/μL. A chest X-ray revealed a homogenous opacification on her right side with a left-sided tracheal deviation while a computed tomography scan of her chest revealed a solid mass on her right side. An echocardiogram showed a huge well-circumscribed mass (4.6×3.3 cm) with spontaneous echocardiographic contrast compressing her heart inferiorly. She had severe pulmonary hypertension (right ventricular systolic pressure 58 mmHg) but preserved left ventricular systolic function, no thrombus was seen, and her pericardium was normal. A computed tomography angiography of her aorta ruled out an aortic aneurysm. Finally, she underwent mediastinoscopy and a direct biopsy of the mass was taken for histopathology. Hematoxylin and eosin staining demonstrated a dense lymphoid infiltrate of large malignant cells with pleomorphic nuclei in clusters, compartmentalized by fine bands of fibrosis, and frequent mitoses were present. A diagnosis of mediastinal large B cell lymphoma was reached. CONCLUSIONS: The presence of a mediastinal widening coupled with a history of unintentional yet significant weight loss in an individual who is human immunodeficiency virus seropositive should raise an index of suspicion for lymphomas and warrant aggressive investigations and timely management.