Occupational Hypersensitivity Pneumonitis in a Japanese Citrus Farmer

Abstract

Hypersensitivity pneumonitis (HP) sometimes develops in people working in specific environments. We herein report a case of occupation-related HP in a citrus farmer in Japan. A 66-year-old man developed a fever, dyspnea, and general malaise in March after working near a trash dump filled with moldy tangerines. He presented with leukocytosis, bilateral lung opacities on chest radiographs, and intra-alveolar and interstitial lymphocytic inflammation with fibrotic change on a lung biopsy. His symptoms disappeared after admission and recurred on a revisit to the workplace. Fungal culture and a mycobiome analysis using next-generation sequencing suggested an association with exposure to Penicillium digitatum.

Keywords: Penicillium digtatum; fungi; hypersensitivity pneumonitis; next generation sequencing; occupational hypersensitivity pneumonitis.

Figure 1.

Radiographic findings of the lungs one week prior to the admission. Chest X radiography (A) showed consolidation in the bilateral lungs, and high-resolution computed tomography demonstrated centrilobular nodules (B) and consolidation along with bronchovascular bundles and traction bronchiectasis (C).

Figure 2.

Pathological findings of a transbronchial lung biopsy sample. Hematoxylin and Eosin staining (A: ×40, B: ×200), Elastica van Gieson staining (C: ×200), and immunohistochemistry of CD68 (D: ×200).