Atypical CT manifestations of pulmonary sarcoidosis

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SummarySarcoidosis is a granulomatous disease of unknown etiol-ogy that affects different organs and tissues. Pulmonary, mediastinal, and intrathoracic lymph nodes involvement occur in about 90% of patients with sarcoidosis. Radio-logical manifestations of pulmonary sarcoidosis vary sig-nificantly. This article describes focal and reticulonodu-lar changes, as well as consolidation zones and fibroticchanges. Isolated reticular changes due to thickening of intra-, and interlobular septa occur in approximately 50% of sarcoid patients. However, this CT pattern pre-vails only in 15–20% of patients. As a rule, in 80% of sar-coid patients changes in lung parenchyma are combined with intrathoracic lymphadenopathy. In the majority of cases, these changes are bilateral. In 10–13% of patients, foci 89–12 mm in diameter are detected. These foci have a homogenous structure and a well-defined outline. They locate mainly along costal and interlobar pleura, in interlobular septa, and may resemble metastases. In 2.4–4% of patients, these small foci, typical for sarcoid-osis are absent, while the changes are presented by larger nodular masses (>2 cm in diameter) or by masses with fuzzy outlines. Often sarcoidosis mimicking interstitial pneumonia is manifested by the ground-glass opacity of spot-like shape. Abnormalities are located in the up-per lobes. This sign occurs in 16–83% of sarcoidotic pa-tients, mainly at the onset of the disease. It usually com-bines with focal changes in the lungs and intrathoracic lymphadenopathy. Cavitary forms of sarcoidosis are also described. Conclusion. There are multiple pulmonary sarcoidosis manifestations on CT, and they vary a lot. The former allows suspecting the diagnosis, which is later confirmed clinically, morphologically, or by lab meth-ods. Аtypical radiological forms of lung sarcoidosis often mimic other pulmonary diseases. These forms require in-vasive diagnostic methods including abdominal surgery.