You’re looking at a chest X-ray, and you see those dramatic, round, well-circumscribed opacities scattered across both lung fields — classic cannonball metastases. 💣
It’s the radiological equivalent of a plot twist. Now the real question: where did these come from?
To help you remember the key cannon ball metastases DDx (differentials), use the mnemonic: “CRASH”
Mnemonic Table: “CRASH”
| Letter | Origin of Metastasis | Notes |
|---|---|---|
| C | Choriocarcinoma | Highly vascular and aggressive. These metastasize like they’re on a world tour. Common in young females with history of molar pregnancy or gestational trophoblastic disease. |
| R | Renal Cell Carcinoma (RCC) | The classic cannonballer. Hematogenous spread with a taste for the lungs. 🩸 CT abdomen is your friend here. |
| A | Adrenal carcinoma | Rare, but when it spreads, it doesn’t hold back. Check for hormone excess as a clue. |
| S | Synovial Sarcoma | A soft tissue sarcoma with a dramatic flair — just like Dr. Faisal Afridi’s ortho cases where the biopsy surprises everyone. |
| H | His Prostate, Her Endometrium | Both can spread hematogenously in advanced stages, though less common. “His and Hers” — like a sinister gift set. 🎁 |
The Case from Panjgur
We had this patient from Panjgur — young male, non-smoker, presents with hemoptysis and weight loss. CT chest shows multiple round, sharply demarcated nodules — classic cannonball appearance.
Initial guess? TB (because, well… Quetta 😅). But sputum was negative, and the CT abdomen? Boom — left renal mass with vascularity.
Dr. Basit Khan muttered, “RCC strikes again. It’s the cannonball king.”
We did the nephrectomy, and the pathology came back clear cell carcinoma. The lungs were already under attack before we could say “interleukin-2.”
🔬 Clinical Tips
- Cannonball metastases = Hematogenous spread — think of tumors with a strong vascular appetite.
- Always correlate with clinical context and primary workup: Beta-hCG for choriocarcinoma, PSA for prostate, imaging for RCC.
- CT Chest and Abdomen is your go-to combo. You can’t fix what you can’t find.
- Don’t over-invest in the “TB reflex” (common in Balochistan): If cannonballs are symmetrical and well-circumscribed, think metastasis first.
That’s all for today, folks! Happy learning! 🙂
Dr. Aurangzaib Qambrani
MBBS, PLAB, MRCP-UK
Sheikh Khalifa Bin Zayed Hospital, Quetta
General Medicine | Gastroenterology | Cardiac Care Unit
