Non-gynaecological Cytology
Respiratory tract cytology
Anatomy and histology of the respiratory tract
Indications of respiratory tract cytology
Cell sampling and preparation methods
Reporting terminology
Normal cells
Non-cellular elements and specimen contaminants
Benign cellular changes
Inflammation
Respiratory infections
Benign lesions
Preneoplastic changes of respiratory epithelium
Lung cancer and other malignant tumours

Bronchioloalveolar carcinoma

It is considered as a variant of pulmonary adenocarcinoma, accounting for about 5% of lung cancers. It is often multifocal, grossly appearing as a pneumonic consolidation. A characteristic feature is its growth along alveolar septa (lepidic growth pattern), without destroying the underlying alveolar architecture. Two subtypes are recognized: the cuboidal non-mucinous type and the mucinous type.

Cytologic diagnostic features (sputum and bronchial washing)

  • Small glandular clusters
  • Regular small cells with large cytoplasm
  • Nuclear hyperchromasia or vescicular nuclei with prominent nucleoli
  • Clean background

Cytologic diagnostic features (FNA and bronchial brushing)

  • Monotonous cell population
  • Arrangements in cellular balls, sheets and papillae
  • Clean background

The bronchioloalveolar carcinoma can be hardly distinguished from classic adenocarcinoma on cytologic preparations. Some cases may strictly resemble a papillary thyroid carcinoma, because of the presence of psammoma bodies, occasional nuclear grooves and pseudoinclusions, optically clear nuclei. Clinical history is helpful to exclude a metastasis.

Immunocytochemistry

  • Cytokeratin 7 +
  • Cytokeratin 5 –
  • Cytokeratin 20 –
  • Neuroendocrine markers +-
  • TTF-1 +
       
     
FNA of BAC - TTF-1

 

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