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c 2019 The Korean Society of Neurogastroenterology and Motility J Neurogastroenterol Motil, Vol. 25 No. 4 October, 2019 www.jnmjournal.org TO THE EDITOR: Nerve fiber degeneration (NFD) is rarely encountered on abdominal surgical resection specimens. We had recently the opportunity to detect NFD on a gallbladder resection specimen. A multifocal neuroma was detected along with an increased number of normally-sized nerves in the gallbladder adventitia. The medical history revealed a cholecystectomy (20-years previously) as well as chronic rhinitis and rheumatoid arthritis. The treatments included methotrexate, etanercept, tetrazepam, omeprazole, and acetylcysteine. The multifocal traumatic neuroma consisted in 6 non-encapsulated foci. These foci, measuring 1-4 mm, showed an increased number of nerve fibers, of varied sizes, densely packed (Figure). One of the foci (1-mm) showed 2 reactive lymphocyte nodules. The largest neuroma-type focus, showed S100and CD56-positive nerve fibers, disposed concentrically, mixed with epithelial membrane antigen-positive perineural cells. A normal-sized nerve, detected at 1 mm from this neuroma-focus showed a rounded, giantcell-shaped degeneration zone. This intra-nerve S100and CD56positive material (and epithelial membrane antigen-negative) contained rare nuclei. There was no inflammatory infiltrate at contact to this nerve. Here we report intra-nerve NFD in a gallbladder adventitia nerve, at proximity to a multifocal post-traumatic neuroma. The NFD was positive for S100 and CD56 and contained rare nerve fiber nuclei. The origin of intra-nerve NFD was difficult to precise. The hypothesis of post-resection, compensatory-type lesions Gallbladder Nerve Fiber Degeneration: Reactive Drug-induced Change? JNM J Neurogastroenterol Motil, Vol. 25 No. 4 October, 2019 pISSN: 2093-0879 eISSN: 2093-0887 https://doi.org/10.5056/jnm19110 Letter to the Editor Journal of Neurogastroenterology and Motility