Gastrointestinal stromal tumors: a contemporary review.

The literature on gastrointestinal stromal tumors (GISTs) has rapidly expanded and has demonstrated how scientific advancements in diagnosis can revolutionize the understanding of disease, while paving the way for effective treatment. While KIT (CD117) immunohistochemistry has established our definition of GISTs, molecular genetics continue to refine it. Elucidation of the aberrant receptor tyrosine kinase (RTK) model of GIST pathogenesis through mutations in c-kit and platelet-derived growth factor alpha PDGFRalpha proto-oncogenes has been prerequisite to the use of imatinib mesylate (STI571, Gleevec; Novartis, Switzerland), a molecular inhibitor of several tyrosine kinases, in the treatment of GISTs. In addition to providing a means for effective treatment, clarification of the molecular pathology of GISTs may potentially offer a new classification of these tumors by correlating genotype with histological, immunohistochemical, and clinical phenotype. This article seeks to review current knowledge of GISTs, offering a practical guide to their diagnosis and describing current epidemiological, molecular biological, and therapeutic aspects.

A patient with anemia of obscure origin: Crohn's disease in disguise.

BACKGROUND: A 65-year-old white Mediterranean male with a 10-year history of intermittent anemia, who was otherwise completely asymptomatic, was referred to our hospital in March 2004. He had a medical history of beta thalassemia and fecal occult blood tests had occasionally been positive. INVESTIGATIONS: Fecal occult blood test, laboratory investigations, esophagogastroduodenoscopy, colonoscopy with retrograde ileoscopy, mesenteric angiography, small-bowel series, CT scan of the abdomen and pelvis, Meckel's scan, and capsule endoscopy. Laparoscopic surgery followed by macroscopic and microscopic histopathologic examination of samples obtained during the procedure. DIAGNOSIS: Crohn's disease of the small bowel. MANAGEMENT: Laparoscopic segmental small-bowel resection with end-to-end anastomosis. Postsurgical treatment with Pentasa 4 g a day.

Enteropathy with loss of enteroendocrine and paneth cells in a patient with immune dysregulation: a case of adult autoimmune enteropathy.

Autoimmune enteropathy (AIE) is a relatively rare condition found most frequently in children. It presents with persistent watery diarrhea and malabsorption and may require total parenteral nutrition for nutritional support. Rare cases have been reported in adults. On histology, the small intestinal villi are flattened but lack the intraepithelial lymphocytosis of celiac disease. In children and rarely in adults, some cases are linked to the IPEX syndrome (Immune dysregulation, Polyendocrinopathy, Enteropathy, X-linked inheritance). We report a 21-year-old man who presented with chronic persistent diarrhea for 4 years. The duodenal biopsies showed villous blunting, chronic inflammation, and decreased to absent goblet cells, Paneth cells, and endocrine cells by histology and electron microscopy. These changes are consistent with an AIE with involvement of non-enterocyte populations. Pathologists must be aware of the possibility of AIE in adults and consider it in the differential diagnosis of duodenitis, intraepithelial lymphocytosis, and small bowel villous flattening.

Colonoscopic diagnosis of mucocele of the appendix.

BACKGROUND: Appendiceal mucoceles are uncommon cystic neoplasms characterized by distension of the appendiceal lumen with mucus. There have been no reported series of colonoscopically diagnosed mucoceles with clinicopathologic correlation. METHODS: A retrospective review of colonoscopies performed at our institution over the past 14 years was undertaken with patient demographics, clinical data, surgical outcomes, and histopathology obtained from hospital records. OBSERVATIONS: Seven patients (6 women) with mucocele of the appendix were identified at colonoscopy. Three had complained of right lower quadrant pain. All 7 patients underwent surgical resection. Histopathology demonstrated mucinous cystadenoma in all. No cases revealed carcinoma, and there have been no deaths related to the mucocele. CONCLUSIONS: Appendiceal mucoceles may be recognized at colonoscopy as a smooth bulbous submucosal lesion of the cecum with an impression formed by the appendiceal orifice. Recognition at colonoscopy is important because it enables accurate diagnosis and directs management. Surgery is recommended in all cases given the risk of malignancy or perforation with resultant pseudomyxoma peritonei.

Given capsule endoscopy in celiac disease: evaluation of diagnostic accuracy and interobserver agreement.

BACKGROUND AND AIMS: Capsule endoscopy (CE) has been increasingly used for diagnosing diseases of the small bowel. It is an attractive technique for assessing celiac disease (CD) because it is noninvasive and provides a close and magnified view of the mucosa of the entire small bowel. In this study, we evaluated the accuracy of CE and interobserver agreement in recognizing villous atrophy (VA) using histopathology as the reference. We also explored the extent of small bowel involvement with CD and the relationship between the length of the affected bowel and the clinical presentation. METHODS: Ten CD patients with histologically proven VA and the same number of controls were subjected to CE. Four, blinded to histology findings, investigators (two with and two without prestudy CE experience) were asked to diagnose VA on CE images. RESULTS: Based on assessment of all four investigators, the overall sensitivity, specificity, PPV, and NPV of CE in diagnosing VA were 70%, 100%, 100%, and 77%, respectively. The sensitivity and the specificity of the test was 100% when the reports of experienced capsule endoscopists only were analyzed. The interobserver agreement was perfect (kappa= 1.0) between investigators with prestudy CE experience and poor (kappa= 0.2) between the investigators who had limited prestudy exposure to CE. Celiac patients with extensive small bowel involvement had typical symptoms of malabsorption (diarrhea, weight loss) as opposed to mild and nonspecific symptoms in patients whose disease was limited to the proximal small bowel. CE was tolerated well by all study participants with 95% reporting absence of any discomfort. CONCLUSIONS: Although based on a small sample size, the study suggests that CE may be useful in assessing patients with CD. Familiarity with CE technology appears to be a critical factor affecting the accuracy of the test. Larger studies are warranted to more precisely define the advantages and limitations of CE in CD.