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Lung Cancer Types: Identifying Non-Lung Cancers (Melanoma Is Skin Cancer)

Melanoma is not a type of lung cancer. It arises from melanocytes in the skin (or rarely mucosa/eye). The three main lung cancer types are:

Primary Lung Cancers

Type% of Lung CancersCell of OriginKey Features
Non-Small Cell Lung Cancer (NSCLC)85%Epithelial (bronchial/alveolar)Adenocarcinoma (most common), squamous cell, large cell. Staged I–IV. Targetable mutations (EGFR, ALK, ROS1, KRAS, etc.).
Small Cell Lung Cancer (SCLC)15%Neuroendocrine (Kulchitsky) cellsAggressive, central, early metastasis. Limited vs. extensive stage. Chemo/RT sensitive but high recurrence.
Lung Carcinoid Tumors1–2%NeuroendocrineTypical (low-grade) vs. atypical (intermediate). Slow-growing; may secrete serotonin (carcinoid syndrome).

Other Tumors in the Lung (Not Primary Lung Cancer)

  • Metastases: Breast, colon, kidney, melanoma, sarcoma → lung (common).
  • Mesothelioma: Pleural (asbestos-related); not lung parenchyma.
  • Lymphoma: Primary pulmonary lymphoma (rare).
  • Benign: Hamartoma, papilloma, chondroma.

Diagnostic Clues

  • Biopsy + IHC: TTF-1, Napsin A (adenocarcinoma); p40, CK5/6 (squamous); Synaptophysin, Chromogranin, CD56 (neuroendocrine); S100, HMB-45, Melan-A (melanoma).
  • Molecular profiling (NSCLC): EGFR, ALK, ROS1, BRAF, MET, RET, KRAS, NTRK, PD-L1.

Correct classification determines treatment: surgery, radiation, chemo, targeted therapy, immunotherapy, or combination.

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