๐ฃ Cannonball metastases = large, round, well-defined pulmonary metastases seen on CXR or CT.
They resemble โcannonballsโ due to their spherical appearance.
๐ซ Most often due to haematogenous spread of malignancy. Their discovery usually indicates advanced disease.
๐ฏ Common Primary Cancers Associated
- Renal Cell Carcinoma (RCC): Classic cause; often presents late with lung mets. ๐ข
- Choriocarcinoma: Aggressive; spreads rapidly to lung, causing hemorrhagic cannonballs. ๐ฉโ๐ผ
- Testicular Cancer (NSGCT): Young men may present with cannonball lesions on CXR. โฝ
- Prostate Cancer: Rare, usually very advanced disease. ๐ง
- Breast Cancer: Can produce pulmonary metastases but less often โcannonball-like.โ ๐
- Sarcomas: Especially osteosarcoma & soft tissue sarcoma. ๐ฆด
- Colorectal Cancer: Occasionally produces round pulmonary metastases. ๐ฝ๏ธ
๐ Radiological Appearance
- Chest X-ray: Multiple, round, well-circumscribed opacities in both lungs โ โsnowstormโ of nodules. ๐จ๏ธ
- CT Scan: Precise size, number, distribution; assesses pleura & nodes. ๐ฅ๏ธ
- Pattern: Bilateral, widespread, random distribution โ hallmark of haematogenous spread. ๐
๐ฉบ Clinical Presentation
- Often asymptomatic: Incidental finding during staging scans.
- Cough & Dyspnoea: From bulk disease or airway irritation. ๐ฎโ๐จ
- Hemoptysis: Due to vascular invasion. ๐จ
- B Symptoms: Weight loss, fever, night sweats, fatigue. โก
๐ Differential Diagnosis
- Primary lung cancer (usually spiculated, not rounded).
- Granulomatous infection โ TB, fungal disease, sarcoid ๐ฆ .
- Rheumatoid nodules (in seropositive RA). โ
- Wegenerโs (GPA) โ cavitating nodules. ๐งฉ
- Septic emboli โ esp. IVDU or endocarditis. ๐
๐งช Diagnostic Workup
- Imaging: CXR โ CT chest โ PET-CT for staging.
- Biopsy: CT-guided or bronchoscopic biopsy for histology & IHC. ๐ฌ
- Tumour Markers:
- ฮฒ-hCG โ choriocarcinoma/testicular cancer.
- AFP โ germ cell tumours.
- PSA โ prostate cancer.
- Systemic staging: Abdomen/pelvis imaging for RCC, germ cell, colorectal. ๐ฅ๏ธ
๐ Management
- Depends on primary tumour:
- RCC โ TKIs, immunotherapy (pembrolizumab, nivolumab). ๐
- Choriocarcinoma โ highly chemo-sensitive (methotrexate, EMA-CO). ๐
- Testicular cancer โ BEP chemo regimen (Bleomycin, Etoposide, Cisplatin). โก
- Breast โ systemic chemo, hormonal therapy, targeted (HER2 agents). ๐
- Surgical resection (metastasectomy): Occasionally considered in limited disease โ e.g., osteosarcoma. ๐ช
- Palliative care: Dyspnoea control (oxygen, opioids), pain management. ๐๏ธ
๐ Prognosis
Generally poor โ indicates advanced systemic disease.
โณ Prognosis varies by tumour biology:
๐ Testicular cancer โ curable, even with cannonball mets (5-year survival >80%).
โ ๏ธ RCC, sarcoma, breast, colon โ worse outcomes, dependent on systemic control.
๐ Prognosis linked more to primary cancer type & treatment response than lung disease itself.