대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pulmonary coccidioidomycosis (acute disease)

Radiologic Findings

On initial chest radiograph after hospital admission, there is a mass-like opacity or consolidation in the right lower lung zone and patchy increased opacity in the left lower lung zone. Multiple nodular opacities are suspected in the right upper and lower lung zones (figure 1).
On initial chest CT scan, there are multiple noncalcified nodules and micronodules in the right upper and right lower lobes and, to a lesser extent, in other areas of the lungs (figure 2, 3). Most nodules are relatively centrilobular in distribution, have ill-defined borders, and less than 1cm in diameter. Also there is relatively segmental consolidation with peripheral ground-glass attenuation in the right lower lobe (figure 3, 4), which shows subtle, internal low attenuation areas on mediastinal window setting, suggesting small lung abscesses (figure 5). Mild, diffuse interlobular septal thickening is also suspected. Bilateral mediastinal and hilar lymph node enlargement is noted (figure 4).

The patient lives in Los Angeles, USA, which is an endemic area of coccidioidomycosis.
Percutaneous transthoracic needle biopsy was performed for the diagnosis of lung disease and the final diagnosis was confirmed to be pulmonary coccidioidomycosis through specimen culture.

Brief Review

Coccidioidomycosis is a fungal infection caused by inhalation of spores from Coccidioides species, endemic to the southwestern United States and arid regions of Mexico, Central America, and South America. The patient in this case lives in Los Angeles in southern California, which is an endemic area. The lungs are the target organ in coccidioidomycosis and are involved in a wide spectrum of clinical and imaging manifestations that are categorized as acute, disseminated, or chronic disease.
Coccidioidomycosis is diagnosed by means of direct visualization of mature spherules with special-stain microscopy or isolation of Coccidioides species from biologic specimens at culture, such as sputum, bronchoalveolar lavage fluid, smear from cutaneous lesions, or tissue biopsy samples. In this case, we performed percutaneous transthoracic needle biopsy at the consolidation in the right lower lobe to confirm the diagnosis. Coccidioides species was identified through culture of the tissue specimens.
Acute symptomatic infection is known as primary coccidioidal infection. After an incubation period of 7-21 days, patients present with symptoms that vary from mild influenza-like illness to acute pneumonia. Some patients develop “valley fever”, an allergic syndrome characterized by hypersensitive skin lesions. This case is also an acute infection, and the patient continued to have fever and cough for 2 weeks.
Thoracic manifestations of the acute disease include pulmonary parenchymal abnormalities, intrathoracic adenopathy, and pleural effusion. The most common lung abnormality is consolidation, occurring in 75% of cases and manifesting as solitary or multiple areas of segmental or lobar opacification. The distribution is mostly unilateral, with perihilar and basilar predominance. The density of parenchymal opacification varies from a ground-glass appearance to dense homogenous consolidation, simulating bacterial pneumonia. Another common parenchymal manifestation is nodular opacities, seen in as many as 20% of cases at chest radiography. They are often multiple and well circumscribed and are seen predominantly in the perihilar and lower lung zones, simulating metastatic disease. Mediastinal adenopathy occurs in cases of severe and prolonged lung infection, and paratracheal or other mediastinal adenopathy suggests a greater risk of disseminated disease. Pleural effusion occurs in 15-20% patients with acute disease. In this case, relatively segmental consolidation and peripheral ground-glass attenuation are seen in the lungs, which mimic bacterial pneumonia.
Disseminated disease is the most severe manifestation of coccidioidomycosis. The classic pulmonary manifestation of disseminated disease is miliary nodules caused by hematogenous spread. Chronic pulmonary coccidioidomycosis is diagnosed when clinical symptoms or imaging abnormalities persist beyond 6 weeks and occurs in 5% of patients. Imaging findings of chronic disease include residual nodule, chronic cavity, persistent pneumonia with or without adenopathy, pleural effusion, and regressive changes.

References

1. Capone D, Marchiori E, Wanke B, et al. Acute pulmonary coccidioidomycosis: CT findings from 15 patients. Br J Radiol. 2008;81(969):721-4.
2. Cecilia MJ, Nita BN, Maitraya KP, et al. Pulmonary coccidioidomycosis: Pictorial review of chest radiographic and CT findings. Radiographics 2014;34:912-925
3. Arsura EL, Kilgore WB. Miliary coccidioidomycosis in the immunocompetent. Chest. 117(2):404-9

Keywords

Lung, Infection, Fungal infection,