CT findings in "pseudoalveolar" sarcoidosis

Radiographic and Histopathologic Features in Sarcoidosis: A Pictorial Display

Sarcoidosis is a multisystemic granulomatous disorder that can affect virtually any organ. However, pulmonary and thoracic lymph node involvement predominates; abnormalities on chest radiographs are present in 80 to 90% of patients with sarcoidosis. High-resolution computed tomographic (HRCT) scans are superior to chest X-rays in assessing extent of disease, and some CT features may discriminate an active inflammatory component (which may be amenable to therapy) from fibrosis (for which therapy is not indicated). Typical findings on HRCT include micronodules, perilymphatic and bronchocentric distribution, perihilar opacities, and varying degrees of fibrosis. Less common findings on CT include mass-like or alveolar opacities, miliary opacities, mosaic attenuation, honeycomb cysts, and cavitation. With progressive disease, fibrosis, architectural distortion, upper lobe volume loss with hilar retraction, coarse linear bands, cysts, and bullae may be observed. We discuss the salient CT findings in patients with sarcoidosis (with a major focus on pulmonary features) and present classical radiographic and histopathological images of a few extrapulmonary sites.

Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.

[The pseudoalveolar form of sarcoïdosis: a diagnostic pitfall]

BACKGROUND

Sarcoïdosis is a benign systemic granulomatosis whose aetiology remains unknown. Lung is the most frequently involved organ. The pseudoalveolar form of this disease is known to have an acute onset and is quite uncommon. Therefore, diagnosing such a rare variety of sarcoidosis is rather often challenging.

OBSERVATIONS

In the present article, the authors report two cases of pseudoalveolar sarcoidosis. The patients, both young adults, showed no suggestive signs of sarcoidosis at first presentation. This resulted in a considerable delay to diagnosis and to the corticosteroid therapy.

CONCLUSION

The authors emphasize the rarity of the pseudoalveolar form of sarcoidosis. They insist on its roentgenographic characteristics and demonstrate the functional benefits allowed by the precocious medical management. They also propose a current review of the literature.

Sarcoidose pulmonar: achados na tomografia computadorizada de alta resolução

A sarcoidose é uma doença sistêmica de causa indeterminada, caracterizada por granulomas não-caseosos. Embora possa afetar qualquer órgão, esta doença tem sua morbi-mortalidade relacionada principalmente ao acometimento pulmonar, presente em 80% a 90% dos pacientes. Este artigo ilustra as principais manifestações pulmonares da sarcoidose na tomografia computadorizada de alta resolução, incluindo as formas típicas e atípicas.

Large coalescent parenchymal nodules in pulmonary sarcoidosis: "sarcoid galaxy" sign

OBJECTIVE

The purpose of this study was to evaluate the large parenchymal nodules in pulmonary sarcoidosis and to describe a new CT sign termed the "sarcoid galaxy."

CONCLUSION

The CT appearance of pulmonary sarcoidosis suggests that the large nodules arise from a coalescence of small nodules. The large nodules are surrounded by many tiny satellite nodules. These findings were considered to simulate the appearance of a galaxy. This observation was supported by radiologic-pathologic correlation. The sarcoid galaxy sign may be a useful adjunct in the diagnosis of pulmonary sarcoidosis.

Pleural involvement in sarcoidosis

Pleural sarcoidosis is no longer considered rare, as it occurs in about 3% of all cases of sarcoidosis. However, newer methods of detection may boost this level higher. High-resolution computed tomographic scanning has increased our detection of pleural nodules and pleural thickening. Other manifestations include pneumothorax, chylothorax, and hemothorax. Further studies of large numbers of patients are needed to determine the true prevalence of pleural involvement in sarcoidosis.

Pulmonary sarcoidosis

Sarcoidosis involves the bronchi or lung in more than 90 percent of patients. Intrathoracic manifestations are protean, ranging from asymptomatic bilateral hilar lymphadenopathy to chronic, progressive, (ultimately fatal), respiratory insufficiency. The clinical course is highly variable, and optimal management and treatment are controversial. We review the salient radiographic, physiologic, and histopathologic features of pulmonary sarcoidosis and discuss rare intrathoracic complications (e.g., bronchostenosis, mycetomas, nodular sarcoidosis, necrotizing sarcoid angiitis and granulomatosis, pulmonary vascular and pleural involvement). We discuss the chest radiographic staging system and the role of ancillary diagnostic modalities including high resolution thin section computed tomographic scans (HRCT), bronchoalveolar lavage, radionuclide scan, and serum angiotensin enzyme converting enzyme. Indications for therapy and an overview of therapeutic options are outlined.