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

Benign clear cell tumor ('sugar' tumor)

It is a rare tumor, occurring in any age as an asymptomatic peripheral nodule. Because of their immunohistochemical and ultrastructural features, they have been supposed to origin from pericytes; anyway, their origin is a matter of discussion. They consist of polygonal cells with clear, glycogen-rich cytoplasm.

Cytologic diagnostic features

  • Clusters of polygonal and spindle-shaped cells
  • Vacuolated or granular cytoplasm
  • PAS-positive cytoplasm

Differential diagnosis

  • Non-small cell carcinoma with clear cell change
  • Carcinoid tumor
  • Metastatic renal cell carcinoma

Immunocytochemistry is helpful: most sugar tumors are positive for HMB-45, CD34 and S-100 and negative for cytokeratins and CEA.

Pulmonary hamartoma

It presents as an incidental nodule on radiographs, particularly in elderly men. A hamartoma is a neoplasm in an organ that is composed of tissue elements normally found at that site, but growing in a haphazard mass.

Transthoracic FNA is very sensitive and specific in diagnosing this lesion. A mixture of mesenchymal (mainly fibromyxoid and cartilaginous material) and epithelial elements is seen in FNA material. Bland spindle cells in a fibromyxoid stroma and mature cartilage, with chondrocyte in lacunae, are observed; epithelial glandular cells and adipocytes are often present.

     
FNA hamartoma
histology hamartoma

 

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