Case and content by Lauren Brown, MD
Expert radiology interpretation by David Godwin, MD
Differentiate metastatic disease to the lung from primary lung malignancy.
45 yo woman with history of Stage IIB cervical cancer, treated with cisplatin and radiation four years ago, presents with two months of progressive dyspnea and nonproductive cough, acutely worsened in the last week and now associated with pleuritic chest pain. She describes one month of drenching night sweats and unintentional weight loss. She was lost to follow-up after treatment for cervical cancer but reports normal mammogram and chest x-ray two years prior. She has a 50 pack-year smoking history.
Numerous bilateral pulmonary nodules, concerning for neoplasm. Right lower lobar collapse concerning for central obstructing mass. Large right pleural effusion.
Is this more likely to represent metastatic disease or primary lung malignancy?
The masses here are circular, well-circumscribed, and while diffusely present are predominant in the bases and periphery (the right-sided pleural effusion and lobar collapse obscures this finding on the right), consistent with diffusely metastatic disease.
Click to view her CT scan.
Primary lung cancers, in contrast, tend to have ill-defined, spiculated margins.
BONUS: “Cannon Ball” Lesions
These are classically described to occur secondary to renal cell carcinoma or choriocarcinoma, and less commonly due to prostatic adenocarcinoma, synovial sarcomas, or endometrial carcinomas; however, in reality, any metastatic process can have this appearance (Dr. Godwin has seen this with melanoma as well).
In French, the term envolée de ballons (“balloon release”) describes the same finding.
DIAGNOSIS AND OUTCOME
Multiple pulmonary metastases due to neuroendocrine neoplasm of unknown primary.
CT chest/abdomen/pelvis showed numerous hepatic, renal, and ureteral lesions as well as colonic thickening consistent with metastases, without clear cervical abnormality or abdominopelvic or retroperitoneal lymph node enlargement to suggest cervical primary. Biopsy of a hepatic lesion identified a well-differentiated, intermediate grade neuroendocrine neoplasm. She chose to pursue further diagnostics and treatment out of state.
TAKE HOME POINTS
- Primary lung cancers tend to have ill-defined, spiculated margins
- Metastases to the lung characteristically have well-defined borders, and are distributed toward the bases and periphery of the lung reflecting hematogenous spread.
- The multiple large, well-circumscribed, round pulmonary lesions seen here are described as “cannon ball” lesions which are due to metastatic disease.