Pulmonary cryptococcoma: a rare and challenging diagnosis in immunocompetent patients

Abstract

Cryptococcal infection is commonly seen in immunocompromised patients, although immunocompetent patients may also be infected. The pathogen's portal of entry is the respiratory tract; however, the central nervous system is predominantly involved. Pulmonary involvement varies from interstitial and alveolar infiltrations to large masses, which are frequently first interpreted as lung neoplasm. The diagnosis of pulmonary cryptococcosis, in these cases, is frequently challenging, which, in most cases, requires histopathological examination. The authors report the case of a young female patient who presented a 20-day history of chest pleuritic pain and fever at the onset of symptoms. HIV serology was negative and CD4 count was normal. The imaging work-up was characterized by a huge opacity in the left inferior pulmonary lobe with a wide pleural base. Computed tomography showed a heterogeneous mass involving the bronchial tree. Mediastinal involvement was poor, and there was a splenomegaly. The patient underwent an exploratory thoracotomy and inferior lobectomy. The histopathological examination revealed a cryptococcoma. As the serum antigenemia was positive, the patient was scheduled for long-term treatment with fluconazole. The authors call attention to including the cryptococcal infection in the differential diagnosis of lung mass, mainly when localized in the lung bases in immunocompetent patients.

Keywords: Cryptococcus; Lung diseases; Pulmonary Surgical Procedures; Therapeutics.

Figure 1. Chest x-ray showing a homogeneous wide pleural base opacity in the inferior left pulmonary lobe.

Figure 2. Thoracic axial computed tomography showing a pulmonary mass with heterogeneous attenuation coefficient in the left lower lobe. A - Mediastinal window; B - Parenchymal window.

Figure 3. Photomicrography of the frozen biopsy. A - Pulmonary parenchyma showing a terminal bronchiole and vessel with altered architecture represented by total replacement of the alveolar tissue by a dense histiocytic infiltration (H&E, 100X); B - Detail of the foamy histiocytic infiltration replacing the alveolar parenchyma (H&E, 200X).

Figure 4. Gross view of the left inferior pulmonary lobe. A - Hilar view; B - Pleural surface view, showing the pleural thickening adhered to the pulmonary parenchyma.

Figure 5. Gross view of the tumoral cross section showing yellowish necrotic areas.

Figure 6. A - Pulmonary parenchyma showing a terminal bronchiole with chronic inflammatory infiltrate and dense histiocytic infiltration replacing the alveoli (H&E, 100X); B - Necrotic area surrounded by granulomas with epitheliod histiocytes and multinucleated giant cells (H&E, 100X); C - Detail of a necrotic area with presence of numerous round birefringent structures with a peripheral halo characteristic of Cryptococcus sp. (H&E, 400X); D - Mucicarmine staining positive decorating the capsule of the Cryptococcus sp yeasts (400X).