Background: Pneumocystis pneumonia (PCP) is common in patients with HIV infection but may also occur in patients with other causes of immunodeficiency, including hematologic and solid malignancies.
Methods: To better describe the clinical picture of PCP as to maintain a high level of suspicion in adequate cases, we studied 56 cancer patients with PCP and compared them to 56 cancer patients with bacterial pneumonia.
Results: Among 56 PCP patients, 44 patients (78.6%) had hematologic malignancies (18 recipients of bone marrow transplantation) and 12 patients had solid tumors. The time since diagnosis was 24 months (range, 4 to 49 months). All patients with solid tumors and 20 patients (45.4%) with hematologic malignancies were receiving steroids. Only six patients were receiving PCP prophylaxis. The main symptoms were fever (85.7%), dyspnea (78.6%), and cough (57.1%). Time from symptom onset was 7 days (range, 3 to 14 days). PCP presented as severe pneumonia (Pao2, 58 mm Hg [range, 50 to 70 mm Hg]) with bilateral interstitial infiltrates (80.4%) and bilateral ground-glass attenuation (89.3%) by CT. Of the 24 ICU patients (42.9%), 16 patients (19.6%) required mechanical ventilation. Eleven patients (19.6%) died. Compared to 56 patients with bacterial pneumonia, PCP patients were more likely to have non-Hodgkin lymphoma and be receiving long-term steroids; they had longer times since diagnosis, longer symptom duration, higher frequencies of fever and of diffuse lung disease (diffuse crackles, bilateral infiltrates, and hypoxemia), higher frequency of ground-glass opacities, and lower frequency of pleural involvement.
Conclusions: PCP presents as subacute, febrile, hypoxemic, and diffuse pulmonary involvement in patients with solid tumors or hematologic malignancies receiving long-term steroids.