Nisan 2012

20-21

Meltem ERGÜN¹, Fatih Oğuz ÖNDER¹, Nesrin TURHAN², Ertuğrul KAYAÇETİN¹

Departments of ¹Gastroenterology and ²Pathology, Yüksek İhtisas Education and Training Hospital, Ankara

Midenin nöroendokrin tümörleri nadirdir, ancak sıklığı giderek artmaktadır. Önceleri cerrahi rezeksiyon tedavi seçenekleri arasında ön plandayken özellikle 2 cm?den küçük tümörlerde endoskopik mukozal rezeksiyon rutin tedavi seçeneği haline gelmiştir. Biz keple mukozektomi yapılarak tedavi edilen bir olguyu sunuyoruz.

Mukozektomi, nöroendokrin tümör, endoskopik rezek siyon

Neuroendocrine tumors (NETs) are a heterogeneous group of rare cancers that derive from neuroendocrine cells and show distinct functional and biological behavior depending on the location, tumor size, and clinical symptoms (1).

NETs are classified histologically based on tumor differentiation. In general, neuroendocrine neoplasms are divided into well-differentiated and poorly differentiated categories. According to the World Health Organization (WHO) 2010 classification, there are three types of NETs: well-differentiated grade 1 (<2 mitoses / 10 high-power fields (hpf) AND <3% Ki67 index), intermediate-differentiated grade 2 (2-20 mitoses / 10 hpf OR 3%-20% Ki67 index) and poorly differentiated grade 3 neuroendocrine cancer (>20 mitoses / 10 hpf OR >20% Ki67 index) (2).

Carcinoid tumors are the most common NETs. Three types of gastric carcinoid tumors are described. Type I: associated with chronic atrophic gastritis, Type II: associated with Zollinger-Ellison syndrome, and Type III sporadic lesions. Gastric carcinoids associated with hypergastrinemia are relatively benign, and endoscopic resection is a feasible treatment modality for lesions that are 2 cm or smaller (3).

Standard treatment for NETs is surgical resection. Endoscopic treatment is an accepted treatment modality for small (≤ 20 mm) submucosal lesions. It has been proven that the small lesion limited in the submucosa with intact muscularis propria has a minimal risk for metastatic disease (4). Conventional snare excision, cap-assisted mucosectomy, submucosal dissection, and unroofing techniques may be preferred depending on the type and size of the lesion (5,6). Cap-assisted endoscopic resection technique is a valid, safe, effective treatment, and it allows total excision of the lesion; therefore, full pathologic assessment is possible to determine the malignant potential.

Standard treatment for NETs is surgical resection. Endoscopic treatment is an accepted treatment modality for small (≤ 20 mm) submucosal lesions. It has been proven that the small lesion limited in the submucosa with intact muscularis propria has a minimal risk for metastatic disease (4). Conventional snare excision, cap-assisted mucosectomy, submucosal dissection, and unroofing techniques may be preferred depending on the type and size of the lesion (5,6). Cap-assisted endoscopic resection technique is a valid, safe, effective treatment, and it allows total excision of the lesion; therefore, full pathologic assessment is possible to determine the malignant potential.

1. Klimstra DS, Modlin IR, Coppola D, et al. The pathologic classification of neuroendocrine tumors: a review of nomenclature, grading, and staging systems. Pancreas 2010;39:707-12. Review.

2. Bosman F, Carneiro F, Hruban R, et al., eds. WHO Classification of Tumours of the Digestive System. Lyon, France: IARC Press, 2010.

3. Scherübl H, Jensen RT, Cadiot G, et al. Management of early gastrointestinal neuroendocrine neoplasms. World J Gastrointest Endosc 2011; 3:133-9.

4. Ruszniewski P, Delle Fave G, Cadiot G, et al. Well-differentiated gastric tumors/carcinomas. Neuroendocrinology 2006;84:158-64.

5. Lee CK, Chung IK, Lee SH, et al. Endoscopic partial resection with the unroofing technique for reliable tissue diagnosis of upper GI subepithelial tumors originating from the muscularis propria on EUS. Gastrointest Endosc 2010;71:188-94.

6. Kim BS, Oh ST, Yook JH, et al. Typical carcinoids and neuroendocrine carcinomas of the stomach: differing clinical courses and prognoses. Am J Surg 2010;200:328-33.