Composite glandular and endocrine tumors of the stomach with pancreatic acinar differentiation.

Composite tumors of the stomach consisting of mixed glandular and endocrine components are rare. We report 3 cases of composite glandular and endocrine tumors with pancreatic acinar differentiation in the stomach with their clinicopathologic findings. The patients' presenting symptoms were variable and included abdominal pain, gastrointestinal hemorrhage, and weight loss. One patient with abdominal pain also had an elevated serum lipase level, clinically mimicking acute pancreatitis. The histology of these tumors was similar. They showed admixture of well-differentiated endocrine components with acinar and glandular components. The glandular component consisted of columnar epithelial cells resembling gastric foveolar or intestinal goblet cells, consistent with a well-differentiated adenocarcinoma. A panel of histochemical and immunohistochemical stains was performed, which included PAS, Alcian blue, Mib1, CEA, cytokeratin 7, cytokeratin 20, Muc2, Muc5AC, chromogranin, synaptophysin, trypsin, chymotrypsin, lipase, insulin, gastrin, serotonin, and pancreatic polypeptide. While the immunoreactivity for cytokeratin 7, cytokeratin 20, Muc2, Muc5AC, and CEA was largely restricted to the glandular component, the endocrine and pancreatic acinar markers showed marked variability and overlap. All cases showed immunoreactivity for at least one of the exocrine pancreatic enzymes, and all expressed endocrine differentiation. Some degree of amphicrine differentiation was suggested in all cases. Two cases showed metastases in perigastric lymph nodes, which histologically resembled the primary tumor. In summary, these tumors represent another distinct type of composite glandular and endocrine gastric neoplasm with pancreatic acinar differentiation.

Recognition of commensal microflora by toll-like receptors is required for intestinal homeostasis.

Toll-like receptors (TLRs) play a crucial role in host defense against microbial infection. The microbial ligands recognized by TLRs are not unique to pathogens, however, and are produced by both pathogenic and commensal microorganisms. It is thought that an inflammatory response to commensal bacteria is avoided due to sequestration of microflora by surface epithelia. Here, we show that commensal bacteria are recognized by TLRs under normal steady-state conditions, and this interaction plays a crucial role in the maintenance of intestinal epithelial homeostasis. Furthermore, we find that activation of TLRs by commensal microflora is critical for the protection against gut injury and associated mortality. These findings reveal a novel function of TLRs-control of intestinal epithelial homeostasis and protection from injury-and provide a new perspective on the evolution of host-microbial interactions.

Benign fibroblastic polyps of the colon: a histologic, immunohistochemical, and ultrastructural study.

Mesenchymal proliferations presenting as mucosal polyps are relatively uncommon and are represented by gastrointestinal stromal tumors, smooth muscle and neural tumors, and inflammatory fibroid polyps. In this report, we describe the clinicopathologic features of a distinctive type of mucosal polyp composed of cytologically bland spindled cells with fibroblastic features. Fourteen cases with histologic features of"fibroblastic polyps" were identified from our case files from January 2000 to December 2003. The clinical and endoscopic findings were reviewed. Immunohistochemistry using a panel of antibodies (vimentin, smooth muscle actin, desmin, CD31, CD34, Bcl-2, c-Kit, S-100, and epithelial membrane antigen) was performed in all cases, and electron microscopy was performed in two cases. The lesions were solitary in all cases and not associated with an identifiable polyposis syndrome. Associated adenomata and/or hyperplastic polyps at different sites were present in 10 cases and hyperplastic polyps were seen in close association in 3 cases. These polyps were characterized by a monomorphic spindle cell proliferation in the lamina propria, without necrosis or mitotic activity. The lesions were intimately associated with the muscularis mucosae and resulted in wide separation and disorganization of the colonic crypts. Immunohistochemical analysis revealed strong and diffuse positivity for vimentin only. Weak and focal reactivity was noted in 2 cases for CD34 and smooth muscle actin, while staining for other antibodies was negative. Electron microscopy revealed sparse cytoplasmic organelles and many intermediate filaments. The histology and ultrastructural and immunohistochemical findings are suggestive of fibroblastic differentiation of these spindle cells. In summary, these lesions represent a distinctive type of colonic mucosal polyp that should be distinguished from other stromal polyps of the gastrointestinal tract.

An unusual case of multiple papillary fibroelastoma, review of literature.

Primary neoplasms of the cardiac valves are extremely rare. However, papillary fibroelastoma is the third most common primary tumor of the heart [Ann Thorac Surg 52 (1991) 1127]. These tumors can be found anywhere in the heart, but most commonly involve the cardiac valves [Ann Thorac Surg 52 (1991) 1127; McAllister HA, Fenoglio JJ. Tumors of the cardiovascular system. In: Atlas of tumor pathology, 2nd series, vols. 1-3. Washington (DC): Armed Forces Institute of Pathology; 1978. p. 20-5]. Most papillary fibroelastomas do not cause symptoms and are usually incidental findings by routine echocardiography or at autopsy. However, early diagnosis of this condition is important, since it represents a surgically correctable cause of systemic emboli, stroke, myocardial infarction, and sudden cardiac death [Ann Thorac Surg 52 (1991) 1127; Ann Thorac Surg 68 (1999) 1881; J Am Soc Echocardiogr 9 (1996) 353; Tex Heart Inst J 22 (1995) 327; Tex Heart Inst J 26 (1999) 298]. The echocardiographic findings should be confirmed by histology, since the clinical differential diagnosis includes myxoma, vegetation, thrombi, lipoma, and pseudopapillary fibroelastoma [Tex Heart Inst J 26 (1999) 298; J Am Soc Echocardiogr 11 (1998) 92; J Natl Med Assoc 87 (1995) 68]. Review of the literature reveals that multiple papillary fibroelastomas are extremely rare [Am Heart J 125 (1993) 1443; J Am Soc Echocardiogr 7 (1994) 315; Ann Thorac Surg 48 (1989) 119]. Li Manduri et al. [J Am Soc Echocardiogr 7 (1994) 315] reported multiple masses on the tricuspid valve, the larger of which was 1 cm in diameter. De Virgilio et al. [Ann Thorac Surg 48 (1989) 119] reported a case of multiple 1-cm papillary fibroelastomas located on mitral valve, left ventricular outflow tract, and along septum. We report an unusual case of multiple papillary fibroelastomas in a woman, who initially was admitted because of a shortness of breath and recent cerebrovascular accident.