Abstract
Background : Schizophyllum commune (S. commune) is a basidiomycete fungus found throughout Japan, commonly in dry logs and dead wood. S. commune is considered edible and is rarely identified as a causative agent of allergic bronchopulmonary mycosis. Herein, we report the cytological and histological features of a typical case of allergic bronchopulmonary mycosis.
Case : A 48-year-old female presented with a 2-week history of persistent fever. A plain chest X-ray revealed evidence of pneumonia in the right middle lobe and mucoid impaction in the rt. B4. Laboratory examination revealed increased serum levels of CRP (12.58 mg/dl) and IgE (5542.6 IU/ml). Serology revealed strongly positive test results for anti-S. commune IgG and IgE antibodies. Transbronchial brush cytology and biopsy were performed to identify the cause of the post-obstructive pneumonia. Cytological and histological finding were as follows. Within a mucinous, inflammatory and allergic background containing eosinophils and Charcot-Leyden crystals, mycotic hyphae were observed. The hyphae were thin and smooth in contour, with a branching mode different from that of Aspergillus fumigatus. Hump-like swellings, called clamp connections, which are known to be characteristic features of S. commune, were visualized near the septae.
Conclusion : S. commune hyphae resemble those of A. fumigatus, which may cause difficulty in the differential diagnosis. However, the characteristic clamp connections of S. commune hyphae can be easily observed in cytological specimens. In patients presenting with pulmonary atelectasis, mucoid impaction and an allergic background, cytological screening bearing in mind the possibility of S. commune is important.
