Neuroendocrine apendicopathy in morphologically normal appendices of patients with diagnosis of acute appendicitis: Diagnostic study

Background About 15%–25% of appendices removed to treat acute appendicitis present normal macro- and macroscopic morphology. The objective of this study was to verify an association of proinflammatory, neuroendocrine and immune mediators with morphologically normal appendices removed from patients with clinical laboratorial and imaging characteristics of acute appendicitis. Materials and methods Appendices removed from 121 adult patients of both genders were distributed into three groups according to their following characteristics: group 1: 53 macro- and microscopically normal appendices from patients with clinical, laboratorial and imaging diagnosis of acute appendicitis; group 2: 24 inflamed appendices from patients with clinical, laboratorial, imaging and histopathological diagnosis of acute appendicitis; group 3: 44 normal appendices from patients submitted to right colectomy to treat localized ascending colon adenocarcinoma. All appendices were immunohistochemically studied for gastrin inhibitor peptide, mast cell tryptase, vascular endothelial growth factor; intestinal vasoactive peptide, tumor necrosis factor alpha, interleukin 1, prostaglandin E2, gene-protein product 9.5, CD8 T lymphocytes, synaptophysine, enolase, and S100 protein. Results The group 1 revealed increased levels of synaptophysine, enolase, mast cell tryptase and PGP-9.5 comparing with the other two groups. The group 2 presented increased levels of interleukin 1, CD8 T lymphocytes and prostaglandin E2 comparing with the other two groups. The group 3 confirmed the normal levels of all these neuroendocrine, immune and proinflammatory mediators. Conclusions Morphologically normal appendices removed from patients with clinical and complementary exams indicating acute appendicitis have appendicular neuroimmunoendocrine disorder associated with the mediators synaptophysin, enolase, mast cell-related tryptase and gene-protein product 9.5.
Highlights • 15 % to 25% of the appendices removed to treat acute appendicitis have normal appearance with no inflammatory signs. • All patients with normal appendices removed due to acute appendicitis do not present similar clinical manifestation anymore. • Inflammatory and neuroendocrine appendicopathies present similar clinical laboratorial and imaging characteristics. • Morphologically normal appendices removed from patients indicating acute appendicitis have neuroimmunoendocrine disorders. • Synaptophysin, enolase, mast cell tryptase and gene-protein product 9.5 are associated with neuroimmunoendocrine disorders.