Pathology of Pulmonary Oncocytoma

 Dr Sampurna Roy MD

Histologically, the tumour is composed of a diffuse proliferation of large polygonal cells with an abundant, granular cytoplasm, and round to irregular nuclei with prominent nucleoli.

Smaller eosinophilic cells with hyperchromatic nuclei and larger vacuolated cells are also observed in some cases.

Reports suggest that no mucin production was detected and there were neither argyrophilic nor argentaffin cells, and no serotonin-positive cells.

Immunohistochemically, the tumour cells were positive for cytokeratins, vimentin and antimitochondrial antigen, whereas alpha-actin, chromogranin, synaptophysin, S-100 protein, and HMB-45 were negative.

According to one study on electron microscopy, abundant microvilli , have been described in pulmonary oncocytomas.

Occasional, desmosomes and myelin figures as well as numerous mitochondria were also seen.

No neurosecretory granules were present.

Based on the findings the authors suggested that the tumor might have an epithelial origin from the bronchial serous gland with subsequent cellular degeneration.