ARRS 2022 Abstracts

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E1345. Pulmonary Adenocarcinoma: Given the Myriad Manifestations When Should You Suspect it on CT?
Authors
  1. Cleonice Isabela Muller; AMO Multidisciplinary Assistance in Oncology
  2. Maria Abreu; Grupo Ressonar
  3. Juliane Serra; AMO Multidisciplinary Assistance in Oncology
  4. Ana Paula Andrade Barreto; AMO Multidisciplinary Assistance in Oncology
  5. Thamine Lessa Andrade; AMO Multidisciplinary Assistance in Oncology
Background
Lung cancer is the leading cause of cancer death in the world, and adenocarcinoma is the most common histological subtype. The CT manifestations are protean, ranging from solitary nodules, which may be ground-glass, part solid, or solid, with or without cystic component, to multiple nodules or masses, focal or multifocal areas of ground-glass opacity and/or consolidation, or a combination of these findings. The manifestations may mimic a number of other lung diseases and thus result in an incorrect or delayed diagnosis.

Educational Goals / Teaching Points
This exhibit aims to illustrate the typical and atypical manifestations of pulmonary adenocarcinoma on CT; -discuss the key clinical and CT features that should raise the suspicion of pulmonary adenocarcinoma, thus allowing a timely diagnosis; and provide a systematic approach using case-based examples of patients with histologically proven diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Features that increase the likelihood of adenocarcinoma include exposure to risk factors, location of the lesion (s), appearance on CT, and doubling time. Risk factors include smoking history, exposure to secondhand smoke, asbestos, radon gas, or other carcinogens, family history of lung cancer, history of extrathoracic cancer, and age whether smokers or not. It is however also more likely to occur in younger individuals, particularly women, than other types of lung cancer. Although adenocarcinoma may occur anywhere in the lung, it is most commonly peripheral and more likely in the upper rather than the lower lobes. CT features that favor adenocarcinoma in solitary lesions include irregular margins and presence of ground-glass opacity, air bronchograms, or bubble lucencies. Lesions with a ground-glass component tend to grow much slower than other types of lung cancer. Multifocal adenocarcinoma may be unilateral or bilateral and manifest as multiple nodules sometimes centrilobular or multifocal areas of ground-glass opacity and/or consolidation, or a combination of these findings. The consolidation is usually associated with air bronchograms and commonly with volume loss and relatively low attenuation resulting in the CT angiogram sign. These findings tend to grow slow over several months or years.

Conclusion
In conclusion, the CT manifestations of pulmonary adenocarcinoma are highly variable and relatively nonspecific. However, the combination of clinical and certain key CT features should raise suspicion for diagnosis and guidance to the optimal approach, whether CT follow-up, PET/CT scan, or biopsy.