Rounded atelectasis of the lung.

Rounded atelectasis of the lung (RA) is a lesion well described in the medical literature, yet often very difficult to diagnose. In recent years, the widespread use of high-resolution imaging modalities employed in the struggle against cancer, coinciding with the peak of the asbestos epidemic, have boosted the detection frequency of RA. However, its differential diagnosis still poses a challenge to the pulmonary specialist and the radiologist, as little is known about its pathogenesis. Furthermore, the multifactorial etiology of RA and its occasional coexistence with lung cancer make the task of confidently ruling out malignancy sometimes daunting. This article attempts to provide an update on RA's etiology, radiological evaluation, clinical management, and prognosis based on recent advances in broadly available diagnostic modalities and minimally invasive interventional procedures. An exemplary case of post-tuberculous RA is illustrated, as RA often presents as an unusual finding of a fairly common disease.