Histopathologic examination revealed that parts of the tumor contained a lobulated architecture composed of sheets, cords, and follicles of chief cells
, oxyphil cells, and clear cells; these findings were consistent with an adenoma.
Chromogranins are proteins within the chief cells
, and S-100 is produced by sustentacular cells (SY38 is another, less specific, marker for neuroendocrine tumors).
Histologically, the cells resemble chief cells
and are uniform, with clear to amphophilic cytoplasm surrounding small, hyperchromatic nuclei (figure, B).
The thymic tissue appeared as a single lobule divided by fine, fibrous septa, and the parathyroid tissue was made up entirely of chief cells
The chief cells
are strongly and diffusely immunoreactive with chromogranin and synaptophysin, while the supporting sustentacular cells react with S-100 protein (figure 2).
Microscopically, the glands are nodular, and examination will identify an increase in parenchymal-cell mass, composed of chief cells
and/or oxyphilic cells (figure).