Lung Cancer (Carcinoma of the Lung)
Lung cancer is broadly categorized into Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC). Each has distinct clinical, histological, and paraneoplastic profiles.
Key Classifications & Dermatological Paraneoplastic Clues
| Type | Key Features | Paraneoplastic Assoc. |
|---|---|---|
| SCLC | Central, aggressive, neuroendocrine origin. | ACTH (Cushing’s), SIADH, Lambert-Eaton. |
| Squamous (NSCLC) | Central, smoking-associated. | PTHrP (Hypercalcemia). |
| Adeno (NSCLC) | Peripheral, most common. | Hypertrophic osteoarthropathy. |
Associated Cutaneous Findings
- Acanthosis Nigricans: While classically associated with GI malignancies, it can occur in rare lung cancer cases.
- Tripe Palms: Thickened, velvety skin on the palms; highly specific for underlying malignancy, particularly lung or gastric cancer.
- Sign of Leser-Trélat: Sudden appearance of multiple seborrheic keratoses.
High-Yield Exam Pearl:
- Squamous Cell Carcinoma (Lung): Remember “CCC”: Central, Cavitation, Calcium (Hypercalcemia via PTHrP).
- Paraneoplastic Dermatosis: Whenever you see “Tripe Palms” in a board-style question, think of internal malignancy (lung cancer if isolated, gastric if accompanied by acanthosis nigricans).