(a)
(b)
(c)
Figure 2: (a) Hematoxylin-eosin stained sections of the adenoma (original magnification ×4 (a-1) and ×40 (a-2)). The adenoma was composed mainly of chief cells and oxyphil cells, covered with a fibrous capsule. No signs of malignancy, such as presence of capsular invasion, angioinvasion, and invasion of the surrounding structures, were observed. (b) Immunostaining for chromogranin A (brown precipitates). Section shows expression of chromogranin A. (c) Immunostaining for PTH (brown precipitates). Section shows expression of PTH.