Eosinophilic globules in pheochromocytoma of the adrenal medulla. A histochemical, immunohistochemical and ultrastructural study.

Histochemical, immunohistochemical, and ultrastructural characteristics of eosinophilic globules in pheochromocytoma of the adrenal medulla are described. The globules were observed in 7 (63.5%) out of 11 cases of pheochromocytoma of the adrenal medulla. These globules were eosinophilic, PAS-positive with and without diastase predigestion, phosphotungstic acid hematoxylin (PTAH) positive, and autofluorescent under ultraviolet illumination. Although almost all globules were not stained with neuron specific enolase (NSE) using the immunoperoxidase method, a few globules were stained positive. The lectins of Triticum vulgaris (WGA) and Ricinus communis (RCA-120) were weakly bound to most of the eosinophilic globules. Immunohistochemical reactions for alpha-fetoprotein (AFP), alpha-l-antichymotrypsin (ACT), and human chorionic gonadotropin (HCG) revealed negative reaction in these globules. An ultrastructural study revealed no relationship between these globules and chromaffin secretory granules. These findings suggested that the eosinophilic globules in pheochromocytoma of the adrenal medulla were not related to the chromaffin secretory granules and might be some kind of complex protein.