Adiaspiromycosis

Synonyms

Haplomycosis. Adiasporosis. Fr: Ger: Sp: Adiaspiromicosis.

Definition

Adiaspiromycosis is a rare pulmonary infection with Chrysosporium parvum var. crescens (formerly Emmonsia crescens). C. parvum var. parvum is not known to infect humans. The organisms are dimorphic, forming large spherical cells (200-400 mm) in tissues: mycelial growth occurs in artificial culture medium at 25 °C.

Geographic Distribution

Adiaspiromycosis occurs worldwide.

Epidemiology and Pathology

Chrysosporium parvum var. crescens is a dimorphic fungus which grows slowly in culture as a septate, branching mycelium. It causes a very rare fungal infection of the respiratory tract. The fungus frequently infects rodents and small carnivorous animals, and is found in the soil around their habitations. Histopathologically, the organism, C. parvum var. crescens, forms large spores and provokes a fibrogranulomatous reaction. The granulomas vary in size from 0.5 to 3 mm and may become confluent. In each patient, all are at the same stage of development. Symptoms are probably caused by compression or displacement of the distal airways and alveolar parenchyma.

There is a cutaneous test of unknown reliability, the diagnosis usually being made by identifying the fungus.

Clinical Characteristics

Most patients are asymptomatic; those with disseminated pulmonary disease have general, nonspecific respiratory symptoms, clinically suggesting flu or in more severe infections, pneumonia. Adiaspiromycosis is often a chance finding, even when disseminated nodules are shown on chest imaging. It is not known to have spread beyond the lungs.

Imaging Diagnosis

Chest radiographs may show a single nodule in the lung parenchyma, usually close to a bronchus. Sometimes there are multiple nodules and in some patients there is pneumonic consolidation, seen most commonly in those who have clinical symptoms. When there has been heavy exposure to the fungus, multiple granulomas have resulted. It must be reemphasized that adiaspiromycosis is often an incidental finding and of no clinical significance.