Coinfection of Pneumocystis jirovecii and Aspergillus fumigatus in the lung

RATIONALE: Coinfection with Pneumocystis jirovecii and Aspergillus fumigatus in immunocompromised patients carries high mortality. More importantly, paradoxical clinical and radiological responses during treatment remain poorly understood. PATIENT CONCERNS: A 66-year-old male with mantle cell lymphoma who had received prolonged corticosteroid therapy after suspected rituximab-associated lung injury presented with progressive pulmonary symptoms. DIAGNOSES: Concurrent pulmonary infection with P jirovecii and A fumigatus was confirmed by bronchoalveolar lavage combined with metagenomic next-generation sequencing. INTERVENTIONS: The patient was treated with trimethoprim-sulfamethoxazole and voriconazole. OUTCOMES: Clinical symptoms improved markedly; however, chest imaging showed paradoxical progression, possibly reflecting an immune reconstitution inflammatory syndrome-like inflammatory response. LESSONS: bronchoalveolar lavage combined with metagenomic next-generation sequencing enables rapid diagnosis of concurrent opportunistic pulmonary infections. Paradoxical radiographic worsening despite clinical improvement may suggest an immune reconstitution inflammatory syndrome-like inflammatory response, although persistent or progressive infection cannot be excluded.