F-18 Fluorodeoxyglucose Positron Emission Tomography in Pulmonary Cryptococcoma

Abstract

Cryptococcosis is not uncommon. Potential interpretation pitfalls should be kept in mind when fluorodeoxyglucose (FDG) positron emission tomography (PET) is used for differentiating pulmonary nodules and for discriminating infection from malignancy, especially in areas where the prevalence of granulomatous infection is high and in immunocompromised patients. In this case, a nodular mass was shown on chest radiography and computed tomographic (CT) scanning. A consolidated infection or a bronchioloalveolar carcinoma was suspected because the CT scan showed air bronchograms within the mass and another perihilar infiltration. The FDG PET scan clearly delineated the lesion and had intermediately high glucose uptake (standard uptake value, 3.8-4.0), which led to the exclusion of the possibility of bronchioloalveolar carcinoma because most of these tumors had normal or mildly increased FDG accumulation. Cryptococcoma was finally diagnosed. Hence, the CT scan and FDG PET played complementary roles in the differential diagnosis of this nodular mass.

Focal Parenchymal Lung Lesions Showing a Potential of False-Positive and False-Negative Interpretations on Integrated PET/CT

“…Previous reports have suggested intermediate increased 18 F-FDG uptake in fungal infections [4]. However, we encountered two cases of fungal infections (aspergillosis and coccidioidomycosis, respectively) that showed intense 18 F-FDG uptake, thereby mimicking lung cancer (Fig.…”

Pulmonary Cryptococcosis: Imaging Findings in 23 Non-AIDS Patients

“…However, the natural course of the disease on imaging studies, particularly how quickly the lung lesions evolve before adequate treatment of the disease and how the lung lesions show response to surgical or antifungal therapy, has not been well documented. Only a few reports document the PET findings of pulmonary cryptococcosis (14-17). Thus, the purpose of our study was to review patterns of lung abnormalities of pulmonary cryptococcosis on CT images, assess the PET findings of the disease, and evaluate the response of lung abnormalities to the different therapies.…”

Computed tomography (CT) and positron emission tomography with [18F]fluoro-2-deoxy-d-glucose (FDG-PET) images of pulmonary cryptococcosis mimicking lung cancer

“…FDG accumulates in macrophages and young granulation tissue caused by pulmonary cryptococcosis [10]. There have been few reports of FDG-PET analysis of pulmonary cryptococcosis, except for one case report by Hsu et al [4]. In the present series, FDG-PET showed accumulation of FDG in all four cases that were examined by this modality, and these cases were difficult to distinguish from lung cancer.…”

“…However, FDG-PET sometimes shows accumulation in inflammatory and granulomatous conditions such as pulmonary cryptococcosis [4]. FDG accumulates in macrophages and young granulation tissue caused by pulmonary cryptococcosis [10].…”

“…Chest computed tomography (CT) frequently shows solitary or multiple nodular shadows, or occasionally cavitation [1,2]. Also, positron emission tomography using [ 18 F]fluoro-2-deoxy-D-glucose (FDG-PET) sometimes demonstrates accumulation in pulmonary cryptococcosis [4]. These features make it difficult to distinguish pulmonary cryptococcosis from lung cancer or tuberculosis.…”