Pulmonary Neoplasms - Lung's Lethal Lineup
- Classification: Small Cell (SCLC) vs. Non-Small Cell (NSCLC) - Adenocarcinoma, Squamous, Large cell.
- Epidemiology: Leading cause of cancer death worldwide. Smoking is #1 risk factor (85-90%).
- NSCLC Subtypes:
- Adenocarcinoma: Most common overall, esp. in non-smokers, women. Peripheral. KRAS, EGFR, ALK mutations.
- Squamous Cell: Central, cavitation. Linked to smoking. PTHrP (hypercalcemia).
- Large Cell: Peripheral, undifferentiated, poor prognosis.
- SCLC: Central, aggressive, early mets. SIADH, Lambert-Eaton. Neuroendocrine origin.
⭐ Most common lung cancer overall is adenocarcinoma, also most common in non-smokers, women, and those < 45 years old.
- Paraneoplastic Syndromes: Common (SIADH, Cushing's, Hypercalcemia, Lambert-Eaton).
- 📌 SPHERE of lung cancer complications: Superior vena cava syndrome, Pancoast tumor, Horner's syndrome, Endocrine (paraneoplastic), Recurrent laryngeal nerve palsy, Effusions (pleural/pericardial).
SPN - Dot Dilemma
- Solitary Pulmonary Nodule (SPN): Focal opacity <3cm, surrounded by lung parenchyma, no associated adenopathy, atelectasis, or pleural effusion.
- Benign vs. Malignant Features:
| Feature | Benign | Malignant |
|---|---|---|
| Margins | Smooth, well-defined | Spiculated, irregular, lobulated |
| Calcification | Dense, Diffuse, Popcorn, Laminated, Central (📌 DDPLC) | Eccentric, stippled, amorphous, absent |
| Cavitation Wall | Thin (<5mm) | Thick (>15mm), irregular |
| Growth (Solid) | Stable >2 yrs | Doubling 20-400 days; interval growth |
| Contrast Enh. | <15 HU | >20 HU |
- Simplified Fleischner Guidelines (Solid Nodules):
Lung Cancer - Mapping Mayhem
Staging is crucial for prognosis and management. Key imaging: CT chest with contrast, PET-CT.
Simplified TNM Staging (8th Ed. Highlights):
| Stage | Key Radiological Correlates |
|---|---|
| T | T1: ≤3cm. T2: >3-5cm or main bronchus, visceral pleura. T3: >5-7cm or chest wall, phrenic nerve, pericardium. T4: >7cm or mediastinum, heart, great vessels, carina. |
| N | N1: Ipsilateral hilar nodes. N2: Ipsilateral mediastinal/subcarinal nodes. N3: Contralateral mediastinal/hilar, supraclavicular nodes. |
| M | M1a: Contralateral lung nodules, malignant pleural/pericardial effusion. M1b: Single extrathoracic metastasis. M1c: Multiple extrathoracic metastases. |
⭐ Common sites of extrathoracic metastasis: adrenals, liver, brain, bone. (📌 Mnemonic: Brain Liver Adrenals Bone - BLAB)
Tumor Types - Character Callouts
| Tumor Type | Location | Cavitation | Effusion | LAD | Notes |
|---|---|---|---|---|---|
| Squamous Cell Ca | Central | Yes | Uncommon | Common | 📌 Central, Cavitation, Cigarettes |
| Adenocarcinoma | Peripheral | Rare | Common | Variable | Non-smokers, lepidic |
| Small Cell Ca (SCLC) | Central | Rare | Common | Bulky | Early mets, paraneoplastic |
| Large Cell Ca | Peripheral | Occasional | Variable | Variable | Large, aggressive |
| Carcinoid (Typical) | Central | No | Rare | Uncommon | Endobronchial, well-defined |
| %%{init: {'flowchart': {'htmlLabels': true}}}%% | |||||
| flowchart TD |
Root["🫁 Lung Cancer
• Primary tumor• Malignant growth"]
%% Path 1: Carcinoid
Carcinoid["🧬 Carcinoid
• Neuroendocrine• Slow-growing"]
TypCarc["🔬 Typical
• Low grade• Fewer mitoses"]
AtypCarc["🔬 Atypical
• Intermediate• Necrosis present"]
%% Path 2: SCLC
SCLC["♋ Small-Cell
• Aggressive type• Central lesion"]
SCC["🔬 Small Cell
• Oat cell type• Rapid spread"]
CSCC["🔬 Combined SC
• Mixed histology• SCLC + NSCLC"]
%% Path 3: NSCLC
NSCLC["♋ Non-Small-Cell
• Most common• NSCLC group"]
Squam["🔬 Squamous
• Hilar mass• Keratin pearls"]
NSquam["🔬 Non-Squamous
• Peripheral mass• Main NSCLC path"]
Saliv["🔬 Salivary
• Glandular type• Rare variants"]
LNEC["🔬 Large Cell NE
• Neuroendocrine• High grade"]
Uncl["🔬 Unclassified
• Other tumors• Rare sub-types"]
%% Sub-path: Non-Squamous Detail
LCC["🔬 Large Cell
• Anaplastic• Large nuclei"]
Adeno["🔬 Adenocarcinoma
• Glandular• Non-smokers"]
AdSquam["🔬 Adenosquamous
• Mixed features• Dual origin"]
OtherNS["🔬 Other NS-NSC
• Rare NSCLC• Misc types"]
%% Connections Root --> Carcinoid Root --> SCLC Root --> NSCLC
Carcinoid --> TypCarc Carcinoid --> AtypCarc
SCLC --> SCC SCLC --> CSCC
NSCLC --> Squam NSCLC --> NSquam NSCLC --> Saliv NSCLC --> LNEC NSCLC --> Uncl
NSquam --> LCC NSquam --> Adeno NSquam --> AdSquam NSquam --> OtherNS
%% Styling style Root fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8 style Carcinoid fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8 style TypCarc fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style AtypCarc fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style SCLC fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8 style SCC fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style CSCC fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style NSCLC fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8 style Squam fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style NSquam fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E style Saliv fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style LNEC fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style Uncl fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style LCC fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style Adeno fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style AdSquam fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252 style OtherNS fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252
> ⭐ Small Cell Lung Cancer (SCLC) is notorious for early metastasis and strong association with paraneoplastic syndromes like SIADH and Lambert-Eaton Myasthenic Syndrome.
## High‑Yield Points - ⚡ Biggest Takeaways
> * **SPN**: Malignancy signs: size >**8mm**, **spiculated margins**, **upper lobe** location.
> * **Squamous Cell Ca**: **Central**, **cavitation**, **hypercalcemia**. **Adenocarcinoma**: **Peripheral**, most common type.
> * **Small Cell Ca**: **Central**, aggressive, **paraneoplastic syndromes** (SIADH, Cushing's).
> * **Pancoast Tumor**: **Apical** location, causes **Horner's syndrome**, **brachial plexopathy**.
> * **Metastases**: Most common lung malignancy overall; multiple **"cannonball" lesions**.
> * **Hamartoma**: Benign; key: **"popcorn" calcification**, **fat density** on CT.
> * **Mesothelioma**: Linked to **asbestos**; key: **pleural thickening**, encasement.