Large cell carcinoma

By definition, large cell undifferentiated carcinoma lacks the microscopic features of the other lung carcinomas, therefore this diagnosis is made by exclusion. It accounts for about 10% of all lung cancers and it is most commonly located peripherally. Histologically, these tumors are characterized by sheets and nests of large cells with vesicular nuclei and prominent nucleoli.
The cytologic diagnosis of malignancy in large cell undifferentiated carcinoma is not difficult.

Rare variants:

  • giant cell carcinoma
  • basaloid carcinoma
  • lymphoepithelioma-like carcinoma
  • clear cell carcinoma
  • large cell carcinoma with rhabdoid phenotype
  • large cell neuroendocrine carcinoma

Cytologic diagnostic features

  • Disorganized groups of large clearly malignant cells
  • Pleomorphic single cells population
  • Variable, often ill-defined and feathery cytoplasm
  • High N/C ratio
  • Irregular nuclei, striking chromatin clearing, multiple nucleoli
  • Intracytoplasmic neutrophils and necrotic background

Differential diagnosis

  • Radiation reaction
  • Degenerating macrophages
  • Large cell non-Hodgkin lymphoma
  • Melanoma
  • Metastatic carcinoma
  • Sarcoma

Necrotic large cell carcinoma:

Necrotic large cell carcinoma
Necrotic large cell carcinoma (sputum)