The distribution of immunoreactive chromogranins, S-100 protein, and vasoactive intestinal peptide in compound tumors of the adrenal medulla.

Three adrenal medullary tumors that showed admixtures of pheochromocytomatous elements with ganglioneuroma or ganglioneuroblastoma were studied to determine the distribution of immunoreactive chromogranins, S-100 protein, and vasoactive intestinal peptide (VIP). Two tumors consisted of typical pheochromocytoma cells admixed with mature-appearing ganglioneuroma. The third consisted of pheochromocytoma admixed with ganglioneuroblastoma and contained many immature and cytologically atypical cells. In all cases, chromogranin staining was absent or weak in neuronal perikarya and moderate to intense in varicosities of neuronal processes, a finding consistent with the presumed distribution of secretory granules in neurons. Chromogranin staining was also intense in chromaffin cells. Glial cells that stained for S-100 were randomly scattered among chromaffin cells but accumulated in areas with neuronal processes. Weak staining for VIP was present in neuronal cells in one of the two tumors with ganglioneuromatous features. Intense staining for VIP occurred in the third tumor in both neuronal and apparently nonneuronal cells. We conclude that granule distribution and cell-cell interactions for specific cell types in compound tumors tend to mimic those in normal adrenal medulla and sympathetic ganglia. Although immunoreactive VIP was localized exclusively to neurons in one tumor, as in normal tissues, patterns of staining for VIP across tumors are less predictable.