A 33-year-old Caribbean Black woman with no prior medical history presented to the emergency department with a 1-week history of fever, dyspnea, and generalized weakness. There was no reported history of night sweats. The patient experienced a 5-month duration of unintentional weight loss of approximately 20 pounds. The patient is a medical doctor; however, there was no exposure to patients with tuberculosis. The family history was significant for first-degree relatives with Hodgkin's lymphoma and cholangiocarcinoma.
The patient was tachycardic at 130 beats per minute, tachypneic at 24 breaths per minute, saturating 92% on high flow nasal cannula. There was decreased air entry at the lower base of the left lung. A chest radiograph revealed complete opacification of the left lung zone ("white-out") and a mediastinal mass. A 12-lead electrocardiogram demonstrated marked sinus tachycardia with secondary ST-T changes suggestive of "demand-ischemia." An arterial blood gas sample was consistent with mixed respiratory and metabolic acidosis. The initial tentative diagnosis was suspected type 1 respiratory failure, likely multifactorial from the large pleural effusion in addition to suspected pulmonary embolism. A subsequent computed tomography "pulmonary embolism protocol" scan confirmed an anterior mediastinal mass (6.9 cm x 3.2 cm x 2.6 cm) with an associated large-sized left pleural effusion with perihilar lymphadenopathy and metastatic nodules. It also revealed a large right atrial thrombus (3.8 cm x 2.5 cm x 3.2 cm) without overt pulmonary emboli (see Figures 1 and 2).
She was subsequently transferred to the intensive care unit, where she was stabilized and initiated upon therapeutic enoxaparin, low-dose aspirin, statin, ivabradine, and beta-blockade based on her high-risk Khorana score of 3. Her routine blood investigations were reflective of dehydration (see Table 1). She also had 350 mL of serosanguinous fluid aspirated from her left lung via thoracentesis. Blood, urine, and pleural fluid cultures returned without bacterial growth. During her ensuing 2-week hospitalization, histopathology revealed features suggestive of thymic carcinoma. Neoadjuvant therapy comprising cisplatin, doxorubicin, vincristine, and cyclophosphamide (ADOC) was commenced. Surgical resection of the mass was performed where it was discovered that the tumor had metastasized to the left lung. Subsequent biopsies confirmed this diagnosis, and the neoplasia was staged as pT4 Nx M1. A transesophageal echocardiogram and cardiac MRI (magnetic resonance imaging) confirmed the presence of the right atrial thrombus (see Figures 1 and 2) with a preserved ejection fraction and no McConnell's sign.
She was discharged on most of her inpatient regimen and also transitioned from enoxaparin to oral rivaroxaban at 15 mg twice daily for 3 weeks, thereafter at 20 mg daily for 3 months based on her intermediate-risk HAS-BLED score of 2. During this period, she underwent six cycles of gemcitabine and capecitabine chemotherapy, and a subsequent computed tomography scan 3 months later revealed near-complete right atrial thrombus dissolution (1.1 cm x 2.1 cm x 0.9 cm) (see Figure 3). She has a scheduled serial scan in 3 months with interim outpatient cardiology follow-up appointments.