Acute eosinophilic pneumonia possibly triggered by occupational exposure to zygomycetes: a histologically confirmed case report

Acute eosinophilic pneumonia (AEP) is often triggered by smoking or inhaled antigens, but AEP associated with zygomycetes (order Mucorales) remains poorly documented. A 56-year-old male tomato farmer presented with cough, dyspnea, and hypoxemia approximately one month after handling mold-infested tomatoes and soil without wearing a mask. Marked eosinophilia was noted in peripheral blood (10,500/μL) and bronchoalveolar lavage fluid (92%). Transbronchial cryobiopsy demonstrated prominent eosinophilic infiltration of the alveoli and interstitium without evidence of vascular invasion. Cunninghamella and Rhizopus species were isolated from sputum and soil cultures, respectively. Following initial mild improvement with empirical antibiotics and antigen avoidance, the patient improved further with corticosteroid therapy, without antifungal treatment, and showed no recurrence during three months of follow-up after discontinuation. Whereas previously reported zygomycete-associated eosinophilic lung disease has progressed to fatal disseminated mucormycosis, this case remained confined to allergic inflammation and followed a favorable clinical course.