Cancer progression in the chest may be challenging to distinguish from benign findings. Both malignant and non-malignant etiologies can manifest as a variety of imaging findings involving the lung parenchyma, pleura, lymph nodes, mediastinum, and chest wall. The spectrum of imaging findings may lead to broad differential diagnoses that include both malignant and benign causes due to overlap in imaging appearances.
Educational Goals / Teaching Points
The goals of this exhibit are to: 1) review pathologies and pitfalls that may mimic cancer progression in the chest, 2) discuss differential diagnoses for common imaging findings of cancer progression, and 3) highlight the overlap in spectrum of malignant and benign findings in the chest using case examples.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Imaging findings include enlarging or new pulmonary nodules or opacities, new pleural abnormalities, enlarging lymph nodes, and new soft tissue or osseous abnormalities. If PET/CT is performed, non-malignant etiologies may have tracer uptake that can mimic cancer progression.
Categories of cancer mimics to be discussed include: infection, trauma, systemic or congenital conditions, and therapy-related / iatrogenic causes.
Non-malignant etiologies may mimic cancer progression in the chest. Careful review of the patient’s history may reveal potential causes for new findings on surveillance imaging. In some cases, follow-up imaging and/or tissue sampling may be needed to definitively diagnose or exclude cancer progression.