TTF1 and tuberous sclerosis: An immunohistochemistry (IHC) panel showed aberrant cytoplasmic expression of octamer-binding transcription factor 4 (OCT-4) in endothelial cells, pericytes, and some astrocyte-type cells; integrase interactor 1 (INI-1) expression was observed in the cytoplasm of neoplastic cells; SEGA was not associated with TSC; the expression of nestin and OCT-4 suggested their origin in neuroepithelial stem cells; thyroid transcription factor 1 (TTF-1) expression supported its origin in diencephalic structures.