Imaging discussion
A lung abscess is defined as a circumscribed area of pus or necrotic
deposits in the lung tissue with the formation of cavities containing
necrotic deposits or fluid caused by a microbial infection, and if
suspected, chest computed tomography (CT) should be done because CT
provides a more accurate anatomical definition than a chest x-ray and
can identify other abscesses and chest lesions that are not clearly
delineated on a chest x-ray 21. On CT, an acute lung
abscess is usually surrounded by a less well-defined area of lung
parenchyma filled with thick necrotic debris, often involving the apical
segment of the inferior lobe of the right lung, which corresponds to the
location in our case 21. Furthermore, in some cases,
CT can distinguish between lung carcinomas and abscesses because
malignant lesions have a thicker wall and are more irregular than
abscesses 21. In our case, this differential diagnosis
was considered due to the presence of irregular borders on CT, absence
of fever, purulent sputum, and leukocytosis, as well as persistence of
the lesion. However, histological studies ruled out malignancy and
confirmed a bacterial lung abscess due to S. intermedius.