Table 3.2 Common diseases manifesting as patchy and nodular consolidation

Note: GGO ground-glass opacity, ANCA antineutrophil cytoplasmic antibody

necrotizing bronchitis and bronchiolitis, typically associated with a neutrophilic inßammatory reaction [26].

Patient Prognosis

Early diagnosis by bronchoscopic examination and aggressive antifungal therapy is the most important step to improve the prognosis. Mortality rate of the patients with lung transplantation is 24 %. However, the prognosis in those with hematologic malignancy or hematopoietic stem cell transplantation is signiÞcantly worse, showing 72 % of mortality [32].

Pulmonary Cryptococcosis

Pathology and Pathogenesis

Pulmonary cryptococcal lesions usually show solitary or multiple relatively well-deÞned, yellow-to-brown, and oval nodular mass or patchy consolidation. Microscopically, aggregates of foamy histiocytes containing cytoplasmic fungi of 6Ð25 um in size are found. They were stained with GMS, PAS, and mucicarmine [33] (Fig. 3.7).

Symptoms and Signs

The clinical presentation of pulmonary cryptococcosis varies from asymptomatic infection to severe pneumonia with

respiratory failure [34]. Symptoms are nonspeciÞc, characterized by cough, fever, dyspnea, pleuritic chest pain, hemoptysis, and malaise. Acute respiratory failure with rapid progression has been reported [35].

CT Findings

Pulmonary cryptococcosis in non-AIDS patients appears with various patterns of lung lesions and indolent course. The most common CT Þndings are multiple clusterednodular patterns, localized to a lung lobe [26]. Other Þndings include single nodular or scattered nodular lesion, mass-like consolidation, and bronchopneumonia pattern. Diffuse involvement including miliary pattern, lymph node enlargement, and cavitation is seen most commonly in immunocompromised patient [36] (Figs. 3.7 and 3.9).

CT–Pathology Comparisons

Nodular pulmonary cryptococcosis (cryptococcomas) histopathologically consists of central zone of necrosis surrounded by a thick Þbrous capsule. At the interface of the nodule and the parenchyma, the alveolar septa are widened by mononuclear inßammatory cells, granulomas, or reactive lymphoid follicles. The airspaces contain foamy macrophages and proteinaceous eosinophilic ßuid collections. These histopathologic Þndings corresponded to the area of a rim of ground-glass opacity around the nodule [37].

Patient Prognosis

Immune status of the patient, severity of pulmonary involvement, and presence of meningoencephalitis determine the treatment regimen for pulmonary cryptococcosis. With the introduction of new less toxic and more effective antifungal drugs, treatment outcome is favorable [38].

IgG4-Related Lung Disease

Pathology and Pathogenesis

Immunoglobulin G4 (IgG4)-related sclerosing disease is characterized clinicopathologically by an elevated serum IgG4 level, Þbrotic inßammation with numerous IgG4positive plasma cells, and a response to steroid therapy. In lung IgG4-related disease, pathology demonstrates a great variety of pulmonary and pleural lesions, and it is important to know the morphologic variety and clinicopathologic characteristics of this disorder [39, 40] (Fig. 3.10).