GRANULAR-CELL TUMOR OF THE APPENDIX IN A PATIENT IRRADIATED FOR A RECTAL-CARCINOMA

We report on a 47-year-old man with a granular cell tumour of the appendix, discovered incidentally during surgery for a rectal adenocarcinoma that had been irradiated preoperatively. A detailed immunocytochemical analysis revealed positivity for S-100 and neuron-specific enolase (NSE). Electron microscopically, the cytoplasm of the tumour cells contained numerous pleomorphic lysosomes. In the appendix tissue adjacent to the tumour a neuroma and the histological features of radiation injury were present. Our findings suggest that this granular cell tumour may have originated from a pre-existing appendix neuroma which underwent granular degeneration, possibly as a result of radiation. © 1990 Springer-Verlag.