title: Long segmental hyperplasia of interstitial cells of Cajal with giant diverticulum formation.
abstract: Sporadic gastrointestinal stromal tumors (GISTs) usually form a well-circumscribed mass. In contrast, diffuse interstitial cell of Cajal (ICC) hyperplasia along the Auerbach plexus without a discrete mass may occur in patients with germline mutations in the NF1, c-KIT or PDGFRA genes. However, sporadic, diffuse ICC hyperplasia without c-KIT or PDGFRA mutations has not been reported. We describe herein one such case, forming a giant diverticulum. A 63-year-old woman with no features of Neurofibromatosis 1 (NF1) presented with increasing abdominal pain for more than 30 years. A large, diverticulum-like mass in the ileum was resected. Microscopically, a diffuse proliferation of bland spindle cells was seen extending for 12 cm, replacing the muscularis propria and lined by intact mucosa. The spindle cells were CD117+/CD34+/DOG1+/SMA+/Desmin-/S100-. Mutation analyses did not reveal any mutations in c-KIT or PDGFRA. The lesion had two silent mutations in the NF1 gene. It is rare of the diffuse form of sporadic ICC hyperplasia showing diffuse longitudinal microscopic growth completely replacing the muscularis propria, mimicking diffuse ICC hyperplasia in hereditary GIST syndromes, but without solid components and no c-KIT or PDGFRA gene mutations. This peculiar form of sporadic ICC hyperplasia may be related to intestinal dysmotility in this ileal segment and giant diverticulum formation.
authors.affiliation: Department of Pathology, Cancer Institute (Hospital), Peking Union Medical College, Chinese Academy of Medical Sciences Beijing, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Xue
authors.forename: Tian
authors.initials: T
authors.lastname: Qiu
authors.forename: Ying
authors.initials: Y
authors.lastname: Song
authors.forename: Ling
authors.initials: L
authors.lastname: Shan
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.forename: Jianming
authors.initials: J
authors.lastname: Ying
authors.forename: Shuangmei
authors.initials: S
authors.lastname: Zou
authors.forename: Susheng
authors.initials: S
authors.lastname: Shi
authors.forename: Alexandros D
authors.initials: AD
authors.lastname: Polydorides
authors.forename: Xinming
authors.initials: X
authors.lastname: Zhao
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Dongmei
authors.initials: D
authors.lastname: Lin
mesh_terms: D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D004252:DNA Mutational Analysis; D004240:Diverticulum / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D016514:Genes, Neurofibromatosis 1; D006801:Humans; D006965:Hyperplasia; D007078:Ileal Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D007150:Immunohistochemistry; D056885:Interstitial Cells of Cajal / Q000737:chemistry / Q000473:pathology*; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D014057:Tomography, X-Ray Computed
chemical_list: D014408:Biomarkers, Tumor; D019009:Proto-Oncogene Proteins c-kit; D020796:Receptor, Platelet-Derived Growth Factor alpha
keywords: ICC hyperplasia; NF1; PDGFRA; c-KIT; giant diverticulum