Patient Prognosis

BALT lymphoma shows the indolent clinical course. The estimated 5- and 10-year overall survival rates have been reported to be 90 and 72 %, respectively [21]. Age and performance status are the prognostic factors.

Pulmonary Infarction

Pathology and Pathogenesis

Infarction in the lungs is generally wedge-shaped and commonly multiple. An occluded pulmonary artery is found at the apex of the infarct; the base of the infarct is on the pleura. Any part of the lung may be affected but infarction is most common at the lung bases. It is classically hemorrhagic and appears as a red-blue area in early stage and becomes paler and red-brown due to hemosiderin deposition. With passage of time, Þbrinous replacement begins and eventually converts the infarct into contracted scar. In thromboembolism, alternatively, the embolus may result in pulmonary infarction, which is indicated clinically by an attack of localized pleural pain, dyspnea, and hemoptysis. Often there is more than one embolic episode [11].

Symptoms and Signs

Acute development of more severe dyspnea, pleuritic chest pain, and blood-tinged sputum are the cardinal symptoms of pulmonary infarction. Purulent sputum is absent. Tachypnea, tachycardia, and hypoxia are found. Lower leg swelling and positive HomanÕs sign can be detected, reßecting deep venous thrombosis.

CT Findings

A peripheral wedge-shaped area of consolidation on CT is suggestive of pulmonary infarction [22]. Internal morphologic characteristics of this consolidation include the presence of central lucencies and the absence of air bronchograms [9] (Fig. 3.6). A slight and continuous FDG uptake at the border of a peripheral lung consolidation (rim sign) can be seen at FDG PETÐCT [23]. Cavitation can occur within the central portion of the consolidation.

The consolidation in pulmonary infarction is mainly caused by central blood alveolar Þlling or central necrosis with a peripheral inßammatory reaction [24]. Central lucencies within consolidation are related to areas of central necrosis surrounded by an inßammatory reaction [9]. A rim of FDG uptake in a pulmonary infarction is related to peripheral inßammatory reaction [23].

Patient Prognosis

Early detection and administration of anticoagulation or thrombolytic therapy is the most important for the management of pulmonary infarction. Pulmonary infarction occurs in approximately 20Ð30 % of patients with signiÞcant cardiac or pulmonary disease, the overall prognosis of pulmonary infarction is worse than pulmonary embolism without infarction.

Patchy and Nodular Consolidation

Definition

Lung parenchymal lesions of opaciÞcation (consolidation, poorly deÞned nodules, or ground-glass opacity), with ill-deÞned margin, are occasionally observed in unilateral or bilateral lungs. The lung abnormalities are spotty, inconsistent, or not uniform (patchy) in distribution. They may appear as multifocal lesions of a single pattern or as a simultaneous combination of various patterns of consolidation, poorly deÞned nodules, and ground-glass opacity. They may involve a single lung (Fig. 3.7) or both lungs.

When the lesions of opaciÞcation appear with discrete margin, we call them multiple nodules or masses (please note Chap. 19).

Diseases Causing the Pattern

This pattern of lung abnormalities can be observed in cryptogenic organizing pneumonia or organizing stage of acute pneumonias [10, 25], extensive bronchopneumonia including airway-invasive pulmonary aspergillosis [26] (Fig. 3.8), fungal infection such as cryptococcosis [27] (Figs. 3.7 and 3.9), diffuse form of adenocarcinoma(s) [18],

Fig. 3.6 Pulmonary embolism and consequent lung infarction in a 32-year-old man with chronic liver disease and deep vein thrombosis. (a) Enhanced CT scan (5.0-mm section thickness) obtained at level of basal trunks shows Þlling defects (arrows, embolism) in the bilateral lower lobar pulmonary arteries. (b, c) Lung window images of CT

scans (2.5-mm section thickness) obtained at levels of the cardiac ventricle (b) and liver dome (c), respectively, demonstrate parenchymal opacity in both lower lobes, particularly in the left lower lobe. Consolidative lesions have disappeared after resolution of pulmonary embolism

lymphoproliferative disease including IgG4-related lung disease [5, 28] (Fig. 3.10) and lymphomatoid granulomatosis

[29] (Fig. 3.11), and pulmonary vasculitis including antineutrophil cytoplasmic antibody (ANCA)-associated granulomatous vasculitis (former WegenerÕs granulomatosis) [30] (Table 3.2).

Distribution

Lesions in the above-mentioned diseases show spotty, inconsistent, or not uniform distribution. The abnormalities may depict their distribution along the bronchovascular bundles.

Clinical Considerations

Airway-invasive pulmonary aspergillosis is a disease in immunocompromised patients (those who have hematologic malignancy and who underwent hematopoietic stem cell transplantation) particularly whose peripheral blood absolute neutrophil count is <500 cells/μL (neutropenia). Cryptococcosis is an indolent lung infection in mildly immunocompromised patients [27]. Generalized symptoms and signs, such as diffuse alveolar hemorrhage, acute glomerulonephritis, chronic refractory sinusitis or rhinorrhea, imaging Þndings of nodules or cavities, and multisystemic disease, precede typical imaging Þndings in pulmonary vasculitis [31].

Fig. 3.7 Pulmonary cryptococcosis appearing as localized consolidation or nodule in a 34-year-old immunocompetent woman. (a, b) Lung window images of CT scans (5.0-mm section thickness) obtained at levels of the cardiac ventricle (a) and liver dome (b), respectively, show large area of consolidation and several poorly deÞned nodules (arrows in b) in the left

lower lobe. (c) Low-magniÞcation (×5) photomicrograph demonstrates relatively well-deÞned, homogeneous consolidation lesion without necrotic portion. (d) High-magniÞcation (×200) photomicrograph displays foreign- body-type giant cells (arrows) and histiocytes (open arrows). Inset: mucicarmine staining highlighting yeast-form organisms (arrowheads)

Fig. 3.8 Airway-invasive pulmonary aspergillosis presenting as multifocal areas of consolidation and branching small nodular lesions in a 46-year-old man who had brain tumor and who received corticosteroid therapy. (a, b) Thin-section (1.0-mm section thickness) CT scans obtained at levels of the bronchus intermedius (a) and basal segmental

bronchi (b), respectively, show patchy areas of consolidation (arrows) and extensive areas of cellular bronchiolitis with tree-in-bud signs (arrowheads) in both lungs. Patient had positive antigen for Aspergillus from his serum. Lesions showed improvement after antifungal therapy

Fig. 3.9 Pulmonary cryptococcosis appearing as patchy areas of consolidation, poorly deÞned nodules, or nodular branching lesions in both lungs in a 37-year-old man. (a, b) Lung window images of CT scans (5.0-mm section thickness) obtained at levels of the aortic arch (a) and main bronchi (b), respectively, show patchy areas of poorly deÞned nodules (arrows), areas of consolidation (open arrows), and tree-in-bud

Key Points for Differential Diagnosis

1.In cryptogenic organizing pneumonia or organizing stage of acute pneumonia, consolidation or poorly deÞned nodules are characteristically distributed along the bronchovascular bundles or the subpleural lungs. The areas of consolidation or nodules may show reversed halo sign [10].

2.Pulmonary cryptococcosis most commonly presents as clustered nodules but also as solitary nodular, scattered nodular, or bronchopneumonic lesion and is a slowly progressive and slowly resolving pulmonary infection [27].

3.Lymphoproliferative disease and IgG4-related lung disease manifest diverse patterns of lung abnormality on CT scans, including a single nodular or consolidative pattern, multiple nodular or areas of consolidation, bronchiectasis and

signs (arrowheads) in both lungs. (c) Low-magniÞcation (×5) photomicrograph demonstrates interstitial pneumonitis and alveolar inßammation. Alveolar spaces are Þlled with numerous macrophages (arrows) and giant cells (open arrows) containing small, cyst-like spaces. Both Gomori methenamine silver and mucicarmine staining disclosed yeastform organisms within the cells

bronchiolitis, and diffuse interstitial lung disease pattern [5, 28].

4. Central necrotic low attenuation within a mass or a nodule, peripheral rim-like enhancement and surrounding ground-glass halo are important characteristic Þndings that may help suggest the diagnosis of pulmonary lymphomatoid granulomatosis [29]. Likewise, in ANCA-associated granulomatous vasculitis, central necrosis, rim enhancement, and halo are also seen, and the necrosis is mainly associated with underlying histopathology of neutrophilic microabscesses or a large zone of geographic necrosis that usually appears deeply basophilic due to the presence of nuclear debris of neutrophils [30, 31]. In both the diseases, there may be cavitation within lesions with airway communication and excavation of the central necrotic portion [29Ð31].