So there I was, standing beside the CT workstation during a sleepy post-call round when Dr. Danish Ramzan peeked over and said,
“Yaar, this lung lesion is throwing more calcium than a dairy farm.” 🐄
Lo and behold, the scan was lit up with calcified pulmonary metastases — an uncommon but exam-gold finding. These aren’t your average fluffy infiltrates. These are the diamonds of lung metastases — rare, rock-hard, and unforgettable.
Let me share the go-to mnemonic that’s saved me (and a few post-call neurons): BOB CAT 🐾
📚 Mnemonic Table: “BOB CAT” for Calcified Pulmonary Metastases
| Letter | Primary Source | Pearls for Practice |
|---|---|---|
| B | Bone tumors (esp. Osteosarcoma) | The classic. Young patient, aggressive lesion, throws calcified cannonballs into lungs like a radiologic rebellion. |
| O | Ovary (Serous cystadenocarcinoma) | Ovarian tumors can metastasize with calcification, sometimes mimicking granulomas. Don’t let the subtlety fool you. |
| B | Breast carcinoma | Occasionally calcified, particularly treated or mucinous variants. Seen it in a case from Mashkai — fooled the whole team. |
| C | Colon cancer | Especially mucinous adenocarcinomas — they love to calcify when they get to the lungs. Because apparently mucus needs mineral reinforcement. 🧱 |
| A | Any treated tumor | Old rule: What doesn’t kill it, calcifies it. Post-chemotherapy or radiotherapy lesions often calcify. Watch for over-calling. |
| T | Thyroid carcinoma | Especially papillary carcinoma — sneaky and slow, but those calcified nodules pop up like surprise guests at a wedding. 🎉 |
🧠 Clinical Scenario from Washuk
A 17-year-old male from Washuk was referred with chronic cough and mild hemoptysis.
X-ray showed multiple bilateral nodules — dense and calcified. Dr. Bilal Chaudhary initially thought they were granulomas.
CT confirmed calcified cannonballs — biopsy later confirmed pulmonary metastases from osteosarcoma.
Lesson? Not all that glitters is TB — especially in Balochistan. 😉
🤓 How to Think on the Spot (especially during vivas or ward rounds):
- Multiple, well-circumscribed, dense nodules → always think metastatic before granulomatous.
- Ask yourself: Is the patient young? Known malignancy? Treated tumor?
- Don’t forget history — a small thyroid lump 3 years ago can come back as calcified lung mets.
- Treated tumors calcify more often — always double-check for therapy history.
Happy learning! 🙂
Dr. Aurangzaib Qambrani
MBBS, PLAB, MRCP-UK
Sheikh Khalifa Bin Zayed Hospital, Quetta
Departments: General Medicine | Gastroenterology | Cardiac Care Unit
