Case report on an unusual pathological triad of oral pyostomatitis vegetans, oral melanoacanthosis, and eosinophilic gastroenteritis in a pediatric patient

Background: Pyostomatitis vegetans (PV) is a rare chronic mucocutaneous disorder that is often associated with inflammatory bowel disease, and comparatively, oral melanoacanthosis is a benign reactive pigmentation of the oral mucosa. Eosinophilic gastroenteritis (EGE) is an uncommon gastrointestinal disorder characterized by eosinophilic infiltration of the gastrointestinal wall. To our knowledge, the coexistence of PV, oral melanoacanthosis, and EGE has not been previously documented. This report explores a potential immunological link among these three diseases and their overlapping inflammatory and clinical manifestations. Case: A 9-year-old Saudi girl presented with oral pigmentation. Her medical history was notable for variable allergies, with symptoms of dysphagia and abdominal pain. Intraoral examination revealed multiple brown macules on the lips, labial mucosa, gingiva, and tongue, as well as cobblestone-like folds in the buccal mucosa. Laboratory investigations demonstrated low iron levels and neutrophil counts, with elevated eosinophil counts and antinuclear antibody levels. Buccal mucosal biopsy revealed features consistent with PV and melanoacanthosis-like changes with melanocytic hyperplasia. These findings supported a diagnosis of PV with atypical melanocytic involvement and suspected gastrointestinal disease. Supportive measures for lip dryness (including lip care and hydration) were recommended, and the patient was referred to a pediatric gastroenterologist. Gastrointestinal work-up included a barium swallow (normal) and endoscopy, which showed moderate esophageal and gastric inflammation, and the biopsies confirmed EGE. The patient was subsequently started on dietary modification instructions, together with proton pump inhibitor therapy and oral corticosteroids, resulting in sustained clinical improvement and stable growth over a 1-year follow-up. Conclusions: This case describes a previously unreported triad of PV, oral melanoacanthosis-like changes, and EGE in a pediatric patient. The overlapping immunological and inflammatory features across these conditions raised the possibility of a common pathogenic mechanism, and awareness of this potential association may facilitate early multidisciplinary diagnosis and management in similar presentations.

Pyostomatitis vegetans; Eosinophilic gastroenteritis; Inflammatory bowel disease; Melanoacanthosis; Buccal mucosa; Oral mucosa

[1] Bardasi G, Romagnoli A, Foschini MP, Mantovani A, Alvisi P. Pyostomatitis vegetans in a pediatric patient with ulcerative colitis: case report of a rare pediatric inflammatory bowel disease extraintestinal manifestation and review of the literature. European Journal of Gastroenterology and Hepatology. 2020; 32: 889–892.

[2] Neville BW, Damm DD, Allen CM, Chi AC. Oral and maxillofacial pathology. 4th edn. Elsevier: Missouri. 2016.

[3] Chrcanovic BR, Martins-Chaves RR, Pontes FSC, Fonseca FP, Pontes HAR, Gomez RS. Pyodermatitis-pyostomatitis vegetans: a case report and systematic review focusing on oral involvement. Oral and Maxillofacial Surgery. 2024; 28: 1405–1414.

[4] Nico MM, Hussein TP, Aoki V, Lourenco SV. Pyostomatitis vegetans and its relation to inflammatory bowel disease, pyoderma gangrenosum, pyodermatitis vegetans, and pemphigus. Journal of Oral Pathology and Medicine. 2012; 41: 584–588.

[5] Yamamoto T. Local neutrophil and eosinophil extracellular traps formation in pyodermatitis pyostomatitis vegetans. Experimental Dermatology. 2024; 33: e14931.

[6] Abellaneda C, Mascaró JM III, Gómez Vázquez M, Martínez-De Pablo I, Iranzo P. All that glitters is not pemphigus: pyodermatitis-pyostomatitis vegetans misdiagnosed as IgA pemphigus for 8 years. American Journal of Dermatopathology. 2011; 33: e1–e6.

[7] Choi JS, Choi SJ, Lee KJ, Kim A, Yoo JK, Yang HR, et al. Clinical manifestations and treatment outcomes of eosinophilic gastroenteritis in children. Pediatric Gastroenterology, Hepatology & Nutrition. 2015; 18: 253–260.

[8] Sunkara T, Rawla P, Yarlagadda KS, Gaduputi V. Eosinophilic gastroenteritis: diagnosis and clinical perspectives. Clinical and Experimental Gastroenterology. 2019; 12: 239–253.

[9] Nelson R, Love L, Krauland K, McCann S. Pyostomatitis vegetans with orofacial and vulvar granulomatosis in a pediatric patient. Cutis. 2022; 110: E11–E15.

[10] Licari A, Votto M, D’Auria E, Castagnoli R, Caimmi SME, Marseglia GL. Eosinophilic gastrointestinal diseases in children: a practical review. Current Pediatric Reviews. 2020; 16: 106–114.

[11] Carlos-Bregni R, Contreras E, Netto AC, Mosqueda-Taylor A, Vargas PA, Jorge J, et al. Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis. Oral Medicine, Oral Pathology and Oral Surgery. 2007; 12: E374–E379.

[12] Abati S, Sandri GF, Finotello L, Polizzi E. Differential diagnosis of pigmented lesions in the oral mucosa: a clinical based overview and narrative review. Cancers. 2024; 16: 2487.

[13] Nigen S, Poulin Y, Rochette L, Lévesque MH, Gagné E. Pyodermatitis-pyostomatitis vegetans: two cases and a review of the literature. Journal of Cutaneous Medicine and Surgery. 2003; 7: 250–255.

[14] Delaporte E, Viget N, Pasturel-Michon U, Catteau B, Hachulla E, Piette F. Pyodermatitis-pyostomatitis vegetans uncovering a case of Crohn disease. Annals of Dermatology and Venereology. 1998; 125: 331–334. (In French)

[15] Aljanobi HA, Alshuyukh MH, Husain MS, Alqahtani WM. Multifocal intraoral melanoacanthomas: two case reports and a literature review. Cureus. 2022; 14: e26946.

[16] Caminiti L, Arasi S, Barni S, Castagnoli R, Gelsomino M, Giovannini M, et al. Eosinophilic gastroduodenitis: a pediatric perspective. Italian Journal of Pediatrics. 2025; 51: 278.

[17] Zammit SC, Cachia M, Sapiano K, Gauci J, Montefort S, Ellul P. Eosinophilic gastrointestinal disorder: is it what it seems to be? Annals of Gastroenterology. 2018; 31: 475–479.

[18] Li M, Jiang W, Wang Z, Lu Y, Zhang J. New insights on IL‑36 in intestinal inflammation and colorectal cancer (review). Experimental and Therapeutic Medicine. 2023; 25: 275.

[19] Jacobs I, Ceulemans M, Wauters L, Breynaert C, Vermeire S, Verstockt B, et al. Role of eosinophils in intestinal inflammation and fibrosis in inflammatory bowel disease: an overlooked villain? Frontiers in Immunology. 2021; 12: 754413.

[20] Low EE, Dellon ES. Review article: emerging insights into the epidemiology, pathophysiology, diagnostic and therapeutic aspects of eosinophilic oesophagitis and other eosinophilic gastrointestinal diseases. Alimentary Pharmacology & Therapeutics. 2024; 59: 322–340.

[21] Daneshjoo R, Talley NJ. Eosinophilic gastroenteritis. Current Gastroenterology Reports. 2002; 4: 366–372.