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Int J Clin Exp Pathol 2013;6(12):2989-2996

Case Report
Long segmental hyperplasia of interstitial cells of Cajal with giant diverticulum formation

Liyan Xue, Tian Qiu, Ying Song, Ling Shan, Xiuyun Liu, Lei Guo, Jianming Ying, Shuangmei Zou, Susheng Shi, Alexandros D Polydorides,
Xinming Zhao, Ning Lu, Dongmei Lin

Departments of Pathology, Imaging Diagnosis, Cancer Institute (Hospital), Peking Union Medical College, Chinese Academy of Medical
Sciences, Beijing, China; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA

Received October 17, 2013; Accepted November 5, 2013; Epub November 15, 2013; Published December 1, 2013

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. (IJCEP1310039).

Keywords: ICC hyperplasia, giant diverticulum, c-KIT, PDGFRA, NF1

Address correspondence to: Dr. Ning Lu or Dr. Dongmei Lin, Department of Pathology, Cancer Institute (Hospital), Peking Union Medical
College, Chinese Academy of Medical Sciences, Beijing 100021, China. Tel: 86-10-87788435; 86-10-87788548; Fax: 86-10-67702630; E-mail:
nlu03@126.com (Ning Lu); lindm3@163.com (Dongmei Lin)