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Squamous Cell Carcinoma of the Lung (SCC)

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Squamous Cell Carcinoma of the Lung (SCC)

Lung squamous cell carcinoma (SCC) is a non-small cell lung cancer (NSCLC) that
typically arises in the central bronchi and is strongly associated with cigarette smoking.

Also called

Epidermoid carcinoma — older term

ICD-10

C34

Specialty

Pulmonology

Onset

Chronic

Reviewed

July 2026

On This Page

Overview

SCC is a centrally located epithelial lung cancer characterized by
keratin production, intercellular bridges, cavitary lesions, and frequent association with
paraneoplastic hypercalcemia due to Parathyroid Hormone Related Protein (PTHrP).

Etiology & Risk Factors

Main cause:

  • Cigarette smoking — strongly associated with lung SCC

Long-term exposure to carcinogens causes:

Bronchial epithelial injury → Squamous metaplasia → Dysplasia → Carcinoma in situ → Invasive SCC

Risk Factors

  • Heavy cigarette smoking
  • Long smoking duration
  • Secondhand smoke exposure
  • Increasing age
  • Occupational exposure to:
    • Asbestos
    • Radon
    • Arsenic
    • Chromium
    • Nickel
  • Air pollution
  • Previous radiation exposure
  • Chronic lung disease

Pathophysiology

• Malignant transformation of bronchial squamous epithelial cells.
• Usually arises centrally from a hilar bronchus.
• Produces keratin and forms intercellular bridges.
• May secrete parathyroid hormone-related peptide (PTHrP), causing hypercalcemia.

Clinical Presentation

-Patients may present with:
• Pulmonary symptoms
• Extrapulmonary symptoms
• Paraneoplastic manifestations
• Features of metastatic disease
-Characteristic features include:
• Central lung mass
• Cavitary lesion arising from a hilar bronchus
• Hypercalcemia due to PTHrP

History Taking

-Assess for:
• Smoking history
• Respiratory symptoms
• Constitutional symptoms
• Symptoms of hypercalcemia
• Symptoms suggestive of metastatic disease

Physical Examination

-Assess for:
• Respiratory findings
• Evidence of hypercalcemia
• General performance status
• Signs of metastatic disease

Investigations of Squamous Cell Carcinoma of the Lung (SCC)​

-Laboratory studies :
• CBC
• Comprehensive metabolic panel
• Hypercalcemia may indicate PTHrP production or bone metastases
• LDH


-Imaging :
• Chest X-ray
• CT chest
Characteristic imaging findings:
• Central lung mass
• Cavitating lesion with air-fluid levels


-Tissue diagnosis:
• Bronchoscopy with transbronchial biopsy (central lesions)
• Histopathological confirmation is required


-Histopathology :
Characteristic findings:
• Keratin pearls
• Intercellular bridges (desmosomes)
• Solid epithelial tumor


-Staging :
May include:
• CT thorax and abdomen
• Brain imaging (MRI preferred)
• PET-CT

Diagnosis of Squamous Cell Carcinoma of the Lung (SCC)​

-Diagnosis is based on:
• Clinical evaluation
• Chest imaging
• Histopathological confirmation by biopsy
• Classification as NSCLC (squamous cell subtype)

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Management Squamous Cell Carcinoma of the Lung (SCC)​

-Management depends on disease stage and should involve a multidisciplinary tumor board whenever available.


Stage I–IIA (No metastases)
• Preferred: Surgical resection with or without chemotherapy
• If not a surgical candidate: Radiotherapy (e.g., stereotactic radiotherapy)


Stage IIB–IIIC
• Preferred: Surgical resection plus chemotherapy
• If inoperable:
• Chemotherapy plus radiotherapy
• Consider adjuvant immunotherapy


Stage IVA–IVB (Metastatic disease)
• Palliative treatment
• If targetable mutation is present:
• Molecular targeted therapy
• If no targetable mutation:
• Chemotherapy and/or immunotherapy

-General principles :
• Early palliative care improves quality of life and may prolong survival.
• Many patients present with advanced disease, making treatment primarily palliative.

Complications

• Hypercalcemia due to PTHrP
• Cavitating lung lesions
• Metastatic disease
• Progressive respiratory compromise

Prognosis of Squamous Cell Carcinoma of the Lung (SCC)​

  • Prognosis depends on the stage at diagnosis.
  • As with other lung cancers, many patients present with advanced disease, resulting in an overall poor prognosis.

Key Points / Clinical Pearls of Squamous Cell Carcinoma of the Lung (SCC)​

• NSCLC subtype.
• Strongly associated with cigarette smoking.
• Usually centrally located.
• Cavitary lesions are characteristic.
• Produces PTHrP → hypercalcemia.
• Histology shows keratin pearls and intercellular bridges.
• Diagnosis requires biopsy.
• Early-stage disease is managed primarily with surgery.
• Advanced disease is treated with chemotherapy, radiotherapy, immunotherapy,
and/or targeted therapy depending on stage and molecular findings.