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

A 46-year-old woman of African descent with a 23-year history of systemic hypertension and a 10-year history of HIV infection on HAART, with an unconfirmed prior AIDS-defining illness was referred to our institution by an upcountry regional hospital. She presented with chief complaints of right-sided facial, neck, upper limb, and trunk swelling together with shortness of breath for 35 days. Her right-sided swelling was of gradual onset and progressive with no identified aggravating or relieving factors. The swelling was associated with difficulty in swallowing, however, she denied any history of associated pain, numbness, color or temperature changes, or impaired vision. She denied any history suggestive of renal dysfunction, oral aphthous ulcers, or candidiasis. Shortness of breath was of gradual onset and worsened with increased right-sided swelling to the extent that regular activities, including walking and speaking, were impaired. It was associated with a dry cough; however, she denied any history of chest pain, night sweats, fever, or symptoms of heart failure. She reported an unintentional weight loss of over 15 kilograms within the past 1 year. She has neither smoked cigarettes nor worked or lived in or near an asbestos company. She reported that she had been diagnosed as having pulmonary tuberculosis (TB) based on radiographic features a year ago and completed a 6-month course of first-line anti-TB drugs; however, she did not present with documents indicating so. Her last hospitalization was 35 weeks prior when she had an episode of expectorating blood-stained sputum; however, her chest X-ray at that time displayed normal findings (Fig. 1a). Another chest X-ray with unidentified indication was done 21 weeks ago and revealed a right-sided mediastinal widening (Fig. 1b). Her CD4 count 29 weeks prior was 743 cells/μL and her last CD4 count 7 weeks prior to the index admission was 284 cells/μL. She was on a zidovudine, nevirapine, and lamivudine regime for approximately 9 years and was then switched to a tenofovir, lamivudine, and efavirenz regime in the past 11 months. The reasons for the regime switch were not documented, however, she reported good adherence throughout. Her husband and daughter of 28 months died of AIDS 10 years ago.

A physical examination revealed an underweight woman with a body mass index (BMI) of 16.8 kg/m², with right-sided facial, neck, upper limb, and trunk swelling together with distended veins on her chest and abdomen draining downwards. Her blood pressure was 138/90 mmHg, respiratory rate 22 breaths/minute, oxygen saturation 97 % on room air, and she had a temperature of 37.1 °C. A respiratory examination revealed reduced chest expansion, stony dull percussion note, and absent breath sounds on her entire right side with a left-sided tracheal deviation. An apex beat was felt at the ninth intercostal space along the mid clavicular line and auscultation revealed a murmur of tricuspid regurgitation. A local breast examination revealed an edematous right breast that was otherwise normal. A musculoskeletal assessment revealed reduced muscle bulkiness in all four limbs but normal tone, power, and reflexes. The lymph nodes in her cervical, axillary, and femoral regions were not palpable.

She underwent a series of investigations which revealed anemia of iron deficiency: hemoglobin (Hb) 8.17 g/dL, mean corpuscular volume (MCV) 79.8 fL, mean corpuscular hemoglobin (MCH) 24.4 pg/cell, and random distribution of red cell width (RDW) 17.1 fL; however, she had normal renal and liver functions, lipids, electrolytes, and bleeding profiles. The Venereal Disease Research Laboratory (VDRL) test for syphilis, serology for hepatitis B and C, and autoimmune screening using antinuclear antibody (ANA) and antineutrophil cytoplasmic antibody (ANCA) were all negative. Mycobacterium tuberculosis was not detected by a GeneXpert test and her present CD4 count is 146 cells/μL. A chest X-ray revealed a homogenous opacification on her right side with a left-sided tracheal deviation (Fig. 1c), and a computed tomography (CT) scan of her chest revealed a solid mass on her right side (Fig. 2). An abdominal ultrasound revealed a right-sided pleural effusion and hepatomegaly (liver span 16.2 cm). An echocardiogram showed a huge well-circumscribed mass (4.6×3.3 cm) with spontaneous echocardiographic contrast compressing her heart inferiorly. There was severe pulmonary hypertension, that is, her right ventricular systolic pressure (RVSP) was 58 mmHg, but she had preserved left ventricular systolic function with an ejection fraction (EF) of 55 %; no thrombus was seen, and her pericardium was normal (Fig. 3). A CT 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. Such biopsy findings are in keeping with a diagnosis of MLBCL. A bone marrow biopsy showed no evidence of lymphoma.

Although the diagnosis was finally reached, she died of respiratory failure a few days before the biopsy results were available.