@article{oai:repository.lib.tottori-u.ac.jp:00005059, author = {Ohnishi, Akemi and Kitamura, Yukisato and Kitamura, Yukisato and Kato, Masako and Kato, Masako and Kawamura, Yoshitomo and Hayashi, Kazuhiko and Hayashi, Kazuhiko and Ohnishi, Akemi and Kawamura, Yoshitomo}, issue = {3}, journal = {Yonago Acta medica, Yonago Acta medica}, month = {Sep}, note = {Pigmented (melanotic) neurofibromas in the appendix are extremely rare. To our knowledge, this is the first case of appendiceal pigmented neurofibroma in a patient without neurofibromatosis 1, which was colonoscopically diagnosed. Histologically, the tumor cells were spindle shaped with indistinct cell borders. The tumor cells had cytoplasms with many gray-brown pigments. Immunohistochemical examinations showed that the tumor cells were strongly positive for S-100 protein, and were focally positive for Melan-A. They were also diffusely positive for Leu7 (CD57), or neuron-specific enolase (NSE). No positive expression of tumor cells was observed for -smooth muscle actin, desmin, CD34, c-kit, HMB45. No mitotic figures were observed. The Ki-67 labeling index was less than 1%. The tumor was thus diagnosed as primary pigmented neurofibroma in the appendix. In the present case, tumor cells showed no mitotic activity and a Ki-67 index of less than 1%, suggesting a benign tumor.}, pages = {65--68}, title = {Pigmented Neurofibroma in the Appendix Diagnosed with Colonoscopy}, volume = {50}, year = {2007} }