Increased nerve twigs in small intestinal mucosa with programmed cell death-ligand 1 and somatostatin receptor type 2A expression in recurrent Crohn disease A case report

Rationale: Inflammatory bowel disease (IBD) patients manifest symptoms of disturbed gut function, such as neural sensory-motor changes. Programmed cell death-ligand 1 (PD-L1), normally present in neural tissue, exists in close apposition to the mucosal immune system and intestinal epithelium, and a bi-directional communication is known to occur at these interfaces. Somatostatin has been shown to suppress the inflammatory reaction, and has been used in several clinical trials to treat inflammatory disorders, such rheumatoid arthritis. Recently, somatostatin receptor type 2A, that regulates neurotransmission, proliferation, and apoptosis, has been recognized in IBD. Although prominent abnormalities in the morphology of the enteric nervous system have been observed in idiopathic IBD, they are more marked in Crohn disease. Patient concerns: A 55-year-old woman with recurrent Crohn disease, just surgically treated for ileal resection, have a stenotic complication. Interventions: At surgery 5 cm of preterminal ileum with stenosis and anastomotic ileocolic block was removed. Diagnoses: The histopathology showed a recurrent Crohn in fistulo-stenotic phase; the stenosis was mainly sustained by mass-forming, ganglioneuromatous hyperplasia. Normally very rare, fine nerve twigs extend up into mucosa but we found a new-formed fibrillary network, extending into the inflammation area at the subepithelial luminal site of the mucosa, that was positive to PD-L1 and somatostatin receptor type 2A (SSTR2A) immunostaining but not visualized in routinary stained slides. Outcomes: After surgery the patient was semestrally followed with clinical endoscopic evaluation that results uneventfully. Lessons: Our case shows that before surgery neuromatous abnormalities can be predicted by immunostained new-formed twigs in the mucosa.