Pulmonary cryptococcosis in non-HIV-infected individuals: HRCT characteristics in 58 patients

Abstract

The aim of this study is to delineate the distinctive high-resolution computed tomography features of pulmonary cryptococcosis in non-HIV-infected patients. This retrospective analysis encompasses high-resolution computed tomography scans from 58 patients with histologically confirmed pulmonary cryptococcosis, focusing on the diagnostic challenges and the factors that lead to misdiagnosis. Analysis of computed tomography scans from these patients indicated that nodular or mass-like presentations were evident in 32 cases (55.2%), consolidation presentations in 7 cases (12.1%), and mixed presentations in 19 cases (32.8%). Lesions were predominantly located in the lower lobes of the lungs (40 cases, 69.0%) and in peripheral zones (55 cases, 94.8%). Notable radiographic signs included the presence of the burr sign in 55 cases (94.8%), lobulation sign in 53 cases (91.4%), halo sign in 53 cases (91.4%), and air bronchogram in 46 cases (79.0%). Moreover, 24 cases (41.4%) exhibited necrosis or cavitation, mediastinal lymphadenopathy was noted in 6 cases (10.3%), and pleural effusion was present in 5 cases (8.6%). Lesions were devoid of calcification. Pulmonary cryptococcosis ought to be contemplated in the differential diagnosis when computed tomography imaging exhibits patterns including, but not limited to, lower lobe and peripheral distribution, a broad base abutting the pleura, clustered growth with a propensity for fusion, air bronchogram within lesions, and peripheral halo sign.

Figure 1.

Representative CT scan of a 39-year-old male patient with hypertension and pulmonary cryptococcosis. (A) The HRCT shows a solid shadow in the lower lobe of the left lung with a broad base adhering to the pleura, and an air bronchogram sign at the proximal end of the shadow (arrow). (B) Nearly 4 months after antifungal treatment with fluconazole, HRCT shows lesions are nearly resolved (arrow). CT = computed tomography, HRCT = high-resolution computed tomography.

Figure 2.

A 31-year-old female, who had no underlying disease and was half a month postpartum, developed a fever of unknown origin accompanied by a sore throat, sticky sputum in the throat region, body aches, and a headache. Laboratory tests indicated an elevated C-reactive protein level. (A) HRCT revealed a solitary mass in the lower lobe of the right lung, with an air bronchogram sign at the proximal end of the lesion and a halo sign around the lesion (arrow). (B) Two weeks after antimicrobial treatment, a new nodular lesion was observed in the dorsal segment of the lower lobe of the right lung (arrow). (C) After obtaining positive serum cryptococcal antigen test results and positively stained tissue specimens, the treatment plan was changed to include fluconazole. A subsequent review of the HRCT at 2 months revealed a reduction in the size of the earliest lesion and the formation of a small internal cavity (arrow). (D) A subsequent review of the HRCT at 5 months demonstrated a further reduction in the size of the earliest lesion (arrow) and the disappearance of the small cavity. HRCT = high-resolution computed tomography.

Figure 3.

Representative CT scan of a 59-year-old diabetic male with pulmonary cryptococcosis. (A, B) HRCT shows multiple nodules clustered in the upper and lower lobes of the right lung with burrs, lobulation, and halo around the lesions (arrow). (C, D) Three months after antifungal treatment with fluconazole, HRCT shows few residual traces (arrow). CT = computed tomography, HRCT = high-resolution computed tomography.