Endocrine GEP-cells in primary testicular teratoma

Differentiated teratomas frequently contain the apparent equivalent of gastrointestinal mucosa. 53 testicular teratomas were investigated for the incidence of entero-endocrine cells. Enterochromaffin(EC)-cells were demonstrated by formaldehyde induced fluorescence (FIF), while the other endocrine cells were identified by immunohistochemistry. 11 of 53 teratomas contained endocrine cells associated with the gastrointestinal epithelium. The most frequently found cell type was the EC-cell, followed by somatostatin-, glucagon- and pancreatic polypeptide-immunoreactive cells. The teratoma tissue blocks (20 of 53) also frequently exhibited normal testicular tissue which did not contain any EC-cell or other entero-endocrine cells. The results are of interest in considering the cytogenesis of entero-endocrine cells and the histogenesis of testicular carcinoids, indicating that the entero-endocrine cells derive from the intestinal carcinoids, indicating that the entero-endocrine cells derive from the intestinal epithelium arising from undifferentiated stem cells. Furthermore, it seems probable that primary testicular carcinoids can develop from pre-existent teratomas by proliferation of their entero-endocrine cells.