A Small Solitary Pulmonary Nodule Discovered by 18F-fluorodeoxyglucose Positron Emission Tomography and CT: Rare Infection Instead of Rare Tumor

Abstract

THE causes of Cushing's syndrome are mainly divided into adrenocorticotropic hormone (ACTH) dependent and independent. ACTH dependent hypercortisolism represents excess ACTH se-creting by the pituitary or tumor outside the pituitary; and the latter one is also called as ectopic ACTH syndrome. Thorax is the most common location of causative lesions for ectopic ACTH syndrome, and the size of lesion is too small to be detected in some cases.1, 2 Cryptococcal pneumonia usually occurs in immunocompromised patients and excess cortisol production can theoretically produce a state of immunodeficiency. Development of cryptococcal pneumonia concomitant with Cushing syndrome (CS) was rare. Here, we report a case of pulmonary nodule in a patient with CS differentiated with ectopic ACTH-producing tumor. Cryptococcal pneumonia was diagnosed following lung resection.