Case Report
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World J Gastroenterol. Feb 7, 2014; 20(5): 1371-1376
Published online Feb 7, 2014. doi: 10.3748/wjg.v20.i5.1371
Bowel mesentery (meso-appendix) microcystic/reticular schwannoma: Case report and literature review
Shao-Xian Tang, Yi-Hua Sun, Xian-Rong Zhou, Jian Wang
Shao-Xian Tang, Jian Wang, Department of Pathology, Shanghai Cancer Center, Fudan University, Shanghai 200032, China
Shao-Xian Tang, Jian Wang, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
Yi-Hua Sun, Xian-Rong Zhou, Department of Pathology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011, China
Author contributions: Sun YH collected the data and pathological materials; Tang SX wrote the paper; and Zhou XR and Wang J proofread the paper.
Supported by National Key Clinical Specialty Project and Key Clinical Program of the Chinese Ministry of Health and the National Natural Science Foundation of China, No. 81272630
Correspondence to: Jian Wang, MD, PhD, Department of Pathology, Shanghai Cancer Center, Fudan University, No. 270, Dong An Road, Shanghai 200032, China. jwang@shca.org.cn
Telephone: +86-21-64176007 Fax: +86-21-64176007
Received: August 30, 2013
Revised: November 3, 2013
Accepted: December 5, 2013
Published online: February 7, 2014
Processing time: 174 Days and 3.5 Hours
Abstract

Microcystic/reticular schwannoma is a recently described variant of schwannoma with a predilection for the gastrointestinal tract. Due to overlapping features with other tumors, unawareness of this tumor type may lead to diagnostic and therapeutic pitfalls. We here report a case of microcystic/reticular schwannoma arising in the meso-appendix of a 43-year-old woman. The tumor was incidentally discovered by computed tomography scan for unrelated reasons. A laparoscopic operation was performed shortly after admission. Histological examination revealed a circumscribed tumor with a striking microcystic and cribriform architecture. Immunohistochemically, the tumor cells were diffusely positive for S100 protein, glial fibrillary acid protein and protein gene product 9.5, which were consistent with a peripheral nerve sheath tumor. The patient remains well with no signs of recurrence at a 10-mo follow-up. To our knowledge, this is the first case of microcystic/reticular schwannoma arising in the meso-appendix. Albeit very rare, microcystic/reticular schwannoma should be included in the differential diagnosis of appendiceal tumors.

Keywords: Laparoscopy; Schwannoma; Appendiceal neoplasms; Immunohistochemistry; Differential diagnosis; Gastrointestinal tract

Core tip: Microcystic/reticular schwannoma is a recently described variant of schwannoma with a predilection for the gastrointestinal (GI) tract. The striking reticular growth pattern and myxoid background may cause confusion with several other tumors commonly seen in the GI tract, in particular a gastrointestinal stromal tumor with prominent myxoid change and a signet ring cell carcinoma, especially on small biopsies. Herein we report for the first time a microcystic/reticular schwannoma arising primarily in the meso-appendix to highlight its existence and enhance pathologist’s and clinician’s awareness of this under-recognized variant of schwannoma so as to avoid misdiagnosis and mistreatment.