Oxyphilic granular cell adenoma (oncocytoma)--a histochemical and ultrastructural study.

Oxyphilic granular cell adenoma (oncocytoma) is extremely rare usually benign neoplasm. Specimens from four oncocytomas of the parotid gland were studied by light microscopy using different histochemical stains, and by electron microscopy. The haematoxylin and eosin stained sections revealed large cells with eosinophilic granular cytoplasm. These granules appear blue with phosphotungstic acid haematoxylin stain, purplish blue with mallory aniline blue stain and are moderately reactive to alcian blue and PAS. No elastic fibers could be seen in the intercellular substance using Verhoeff's stain. At the ultrastructural level, the tumour cells were characterized by great numbers of mitochondria. Many of the mitochondria contained glycogen granules. Dividing mitochondria were also observed.

Ultrastructural features of vocal fold nodules and polyps.

Earlier investigation did not show any clear distinctive pathological features that differentiate vocal polyps from vocal nodules. The light microscopic distinctive features between the two lesions point in the direction of a more pronounced epithelial reaction and a more fibrous stromal change in vocal nodules. In the present study, 19 vocal polyps and 11 vocal nodules were subjected to ultrastructural examination aiming at finding distinctive features that may be pathognomic for each of these clinically distinct entities. The study was carried out by EM Philips 400 T. The results demonstrate that nodules showed epithelial changes in the form of gaping of the intercellular junctions and absence of the basal lamina in parts. These changes are less apparent in polyps, whereas the stromal changes are more pronounced and varied. The significance of these results and their interpretation are discussed.