Secondary parathyroid hyperplasia in tuberous sclerosis: report of a case with large eosinophilic ganglion-like cells similar to those of subependymal giant cell astrocytoma, tubers, and atypical angiomyolipoma.

We report a case of secondary parathyroid hyperplasia in a 49-year-old man with tuberous sclerosis. Two parathyroid glands had collections of large, eosinophilic ganglion-like endocrine cells that to our knowledge have not been previously described at this site. These cells are morphologically similar to those of subependymal giant cell astrocytoma, tubers, and atypical angiomyolipoma, all of which may arise in the setting of tuberous sclerosis. These large, eosinophilic ganglion-like cells found in different affected organs appear to be distinctive of tuberous sclerosis. We suggest these large eosinophilic cells arise from a common stem cell precursor that acquires variable phenotypes according to alterations in the cellular microenvironment.