Ian S. Brown

Intraepithelial Lymphocytosis in Architecturally Preserved Proximal Small Intestinal Mucosa An Increasing Diagnostic Problem With a Wide Differential Diagnosis

CONTEXT An increased intraepithelial lymphocyte density in an architecturally normal proximal small intestinal mucosal biopsy is a common finding facing surgical pathologists dealing with gastrointestinal biopsy specimens. Approximately 1% to 2% of all proximal small intestinal biopsies will show this change. It is increasingly recognized by surgical pathologists that gluten-sensitive enteropathy is an important cause of this pattern; however, gluten-sensitive enteropathy accounts for the minority of all cases. A wide variety of immunologic stimuli can raise intraepithelial lymphocyte numbers. Among the other common associations are enteric infection, autoimmune disease, drugs, and gastric Helicobacter infection. OBJECTIVE To outline the causes of intraepithelial lymphocytosis, to highlight the importance and the difficulties faced in establishing gluten-sensitive enteropathy as the cause, and to aid the surgical pathologist in the routine sign out of these cases. DATA SOURCES A review of the literature detailing the causes or associations of proximal small intestinal intraepithelial lymphocytosis is presented. CONCLUSIONS Increased lymphocyte numbers in the epithelium of architecturally preserved proximal small intestinal biopsies is a morphologic feature associated with a broad differential diagnosis.

High-Risk Human Papillomavirus in Esophageal Squamous Cell Carcinoma

Background: Although most cases of esophageal squamous cell carcinoma (ESCC) in western populations have been attributed to high levels of exposure to tobacco and alcohol, infectious agents have been postulated as possible causes, particularly human papillomavirus (HPV). Methods: To explore this issue, we analyzed HPV DNA prevalence and HPV types together with lifestyle factors, in relation to tumor stage and survival in a low-incidence population. Archived tumor samples from a nationwide cohort of 222 ESCC patients were tested for the presence of HPV DNA by PCR; positive samples were sequenced to determine HPV type, and p16INK4a status was assessed by immunohistochemistry. Results: Of 222 ESCC patients, 8 tested HPV positive (prevalence, 3.6%; 95% confidence interval, 1.1-6.1%), of which 6 were HPV-16 positive and 2 were HPV-35 positive. Four of the eight HPV-positive tumors overexpressed p16INK4a. None of 55 normal esophageal tissue samples from healthy participants had any detectable HPV. Although the numbers were low, it seemed that patients with HPV-positive ESCC tumors were younger than those with HPV-negative tumors (mean age, 60.8 versus 65.3 years, P = 0.18) and had higher body mass index (BMI) throughout life (mean current BMI of 25.1 for HPV positive, 22.2 for HPV negative, P = 0.08; mean BMI at 20 years of 25.8 for HPV positive, 22.1 for HPV negative, P = 0.003). We found no difference between patients with HPV-positive and HPV-negative tumors with respect to other lifestyle factors. Conclusions: These findings suggest a very low prevalence of HPV DNA in human ESCC. Impact: HPV is very unlikely to be a common cause of ESCC in Australia. Cancer Epidemiol Biomarkers Prev; 19(8); 2080–7. ©2010 AACR.

A clinicopathological and molecular analysis of 200 traditional serrated adenomas

The traditional serrated adenoma is the least common colorectal serrated polyp. The clinicopathological features and molecular drivers of these polyps require further investigation. We have prospectively collected a cohort of 200 ordinary and advanced traditional serrated adenomas and performed BRAF and KRAS mutational profiling, CpG island methylator phenotype analysis, and immunohistochemistry for a panel of 7 antibodies (MLH1, β-catenin, p53, p16, Ki67, CK7, and CK20) on all cases. The mean age of the patients was 64 years and 50% were female. Of the polyps, 71% were distal. Advanced histology (overt dysplasia or carcinoma) was present in 19% of cases. BRAF mutation was present in 67% and KRAS mutation in 22%. BRAF mutant traditional serrated adenomas were more frequently proximal (39% versus 2%; P≤0.0001), were exclusively associated with a precursor polyp (57% versus 0%; P≤0.0001), and were more frequently CpG island methylator phenotype high (60% versus 16%; P≤0.0001) than KRAS mutant traditional serrated adenomas. Advanced traditional serrated adenomas retained MLH1 expression in 97%, showed strong p53 staining in 55%, and nuclear β-catenin staining in 40%. P16 staining was lost in the advanced areas of 55% of BRAF mutant traditional serrated adenomas compared with 10% of the advanced areas of KRAS mutant or BRAF/KRAS wild-type traditional serrated adenomas. BRAF and KRAS mutant traditional serrated adenomas are morphologically related but biologically disparate polyps with distinctive clinicopathological and molecular features. The overwhelming majority of traditional serrated adenomas retain mismatch repair enzyme function indicating a microsatellite-stable phenotype. Malignant progression occurs via TP53 mutation and Wnt pathway activation regardless of mutation status. However, CDKN2A (encoding the p16 protein) is silenced nearly exclusively in the advanced areas of the BRAF mutant traditional serrated adenomas. Thus, the BRAF mutant traditional serrated adenoma represents an important precursor of the aggressive BRAF mutant, microsatellite-stable subtype of colorectal carcinoma.

Foveolar type dysplasia in Barrett esophagus.

Adenocarcinoma of the lower esophagus and esophagogastric junction is increasing in incidence in Western countries. A metaplasia (Barrett esophagus)—dysplasia—carcinoma sequence induced by gastroesophageal reflux disease is established. Two patterns of Barrett dysplasias have been described—adenomatous (type 1) and non-adenomatous (type 2 or foveolar/hyperplastic type). Interestingly, little is known about non-adenomatous dysplasia. Esophagogastrectomy cases from 41 patients with glandular dysplasia with and without associated invasive adenocarcinoma of the lower esophagus were evaluated for expression of MUC2, MUC5AC, CDX2, villin, Ki67 and p53. Results were correlated with sub-classification of the dysplasia into morphologic patterns of adenomatous vs foveolar vs hybrid type. In addition, clinicopathological parameters including the presence and extent of background intestinal metaplasia were also evaluated. Foveolar type dysplasia was present in 46% of the cases and thus, was more common than adenomatous type or hybrid type (both ∼27%) dysplasia. Immunohistochemistry confirmed the histological stratification in all cases. Foveolar type dysplasia commonly expressed MUC5AC (P<0.12) but was consistently negative for markers of intestinal differentiation, MUC2, CDX2 and villin (all P<0.01). By contrast, adenomatous type dysplasia frequently displayed intestinal differentiation markers (all P<0.0001) Hybrid-type dysplasia was similar to adenomatous type dysplasia in showing expression of intestinal differentiation markers (P<0.01) and therefore could not be sustained as a separate category. In conclusion, our study provides evidence for a non intestinal pathway to neoplastic development in Barrett esophagus, that is, gastric metaplasia—foveolar dysplasia—adenocarcinoma.

Gastrointestinal pathology in celiac disease: A case series of 150 consecutive newly diagnosed patients

The main histologic feature of celiac disease is increased intraepithelial lymphocytes (IELs) with or without villous atrophy of the duodenal mucosa. The aim of this study was to document a broad range of additional morphologic changes in intestinal mucosa biopsy specimens from patients with celiac disease. Our cohort comprised 150 patients with positive tissue transglutaminase serologic findings; 7 were at Corazza stage A1, 58 at stage B1, and 85 at stage B2. IEL counts per 100 epithelial cells ranged from 34 to 156 (mean, 88.6); a significant neutrophilic infiltrate was present in 85 cases (56.7%); eosinophil count ranged from 3 to 50 per high-power field (mean, 14.6). Additional findings included morphologic changes in enterocytes in 68.7%, subepithelial collagen thickening in 45.3%, and associated lymphocytic gastritis in 30.4% of patients. We demonstrated that these underrecognized features, which can be misleading, are not uncommon in celiac disease and were positively associated with more advanced stages of the disease (P < .0001).

Collagenous sprue: a clinicopathologic study of 12 cases.

Collagenous sprue is a rare form of small bowel enteropathy characterized by chronic diarrhea and progressive malabsorption with little data available on its natural history. The pathologic lesion consists of subepithelial collagen deposition associated with variable alterations in villous architecture. The small bowel biopsies of 12 cases were reviewed. Clinical details, celiac serology, and T-cell receptor gene rearrangement study results, when available, were collated. There were 8 females and 4 males (age ranged from 41 to 84 y) who presented with chronic diarrhea and weight loss. Small intestinal biopsies showed subepithelial collagen deposition with varying degrees of villous atrophy and varying numbers of intraepithelial lymphocytes. Four patients had previous biopsies showing enteropathic changes without collagen deposition. Seven cases were associated with collagenous colitis and 1 also had features of lymphocytic colitis. Three patients also had collagen deposition in gastric biopsies. One case was associated with lymphocytic gastritis. Celiac disease (CD, gluten-sensitive enteropathy) was documented in 4 patients. Five patients made a clinical improvement with combinations of a gluten-free diet and immunosuppressive therapy. Two patients died of complications of malnutrition and 1 of another illness. Clonal T-cell populations were identified in 5 of 6 cases tested. Four of these patients improved clinically after treatment but 1 has died. Collagenous sprue evolved on a background of CD in 4 cases. There was no history of CD in others and these cases may be the result of a biologic insult other than gluten sensitivity. None has developed clinical evidence of lymphoma to date.

Tropical sprue: revisiting an underrecognized disease.

Tropical sprue is an acquired chronic diarrheal disorder of unclear etiology affecting residents of and visitors to tropical regions. Patients usually present with profuse diarrhea, weight loss, and malabsorption, notably of vitamin B12 and folate. The histologic changes typically resemble that of gluten-sensitive enteropathy. Reports of tropical sprue have become infrequent in the literature, and the diagnosis is often not considered either clinically or pathologically. This disease may, however, cause significant morbidity, although it is eminently treatable with broad-spectrum antibiotics. In this study, we report the clinical presentation of 12 tropical sprue patients along with the histologic changes of the intestinal mucosa and compare it with those of a series of 150 cases of gluten-sensitive enteropathy, the condition with which it is most frequently misdiagnosed. The cohort comprised 6 men and 6 women with a median age of 59 years (range, 38 to 78 y) with a history of residence or visitation in South Asia or Papua New Guinea. Partial villous blunting in the duodenal mucosa was present in 75% of cases, and a marked intraepithelial lymphocytosis was observed in all cases (mean per 100 epithelial cells 77.3; range, 42 to 124). A villous tip accentuation of intraepithelial lymphocytosis was not appreciable in most cases. No case of complete villous blunting (Marsh stage 3c) was identified in tropical sprue, contrasting with 25% in gluten-sensitive enteropathy cases. A duodenal mucosa eosinophil infiltrate was present in all cases with significantly higher counts compared with untreated gluten-sensitive enteropathy patients (26.6/HPF vs. 14.6/HPF; P=0.009). The ileal mucosa displayed more severe villous blunting with higher Marsh stages than in the corresponding duodenum from 5 patients. There was a mild intraepithelial lymphocytosis and eosinophil infiltrate in the colonic mucosa of half of the cases. Follow-up biopsies in 6 patients demonstrated a histologic response after oral folates and doxycycline treatment. In summary, tropical sprue is a pan-enteric inflammatory process often mistaken for gluten-sensitive enteropathy. Histologic findings suggesting tropical sprue in the appropriate clinical context include incomplete duodenal villous blunting without development of flat mucosa, frequent involvement of the terminal ileum with more marked inflammation and villous blunting than in the duodenum, and a conspicuous eosinophil infiltrate in the lamina propria. With the expansion of tourism and increasing employment opportunities in tropical regions, pathologists in the West are increasingly likely to encounter cases of tropical sprue and should be aware of this diagnosis.

The challenging diagnosis of Cronkhite-Canada syndrome in the upper gastrointestinal tract: a series of 7 cases with clinical follow-up.

Cronkhite-Canada syndrome is a rare protein-losing enteropathy, classically characterized by ectodermal changes and gastrointestinal polyposis. The etiology remains obscure but immune dysregulation may be important. The diagnosis of Cronkhite-Canada syndrome in the upper gastrointestinal tract is challenging, frequently resulting in delayed patient management. In this study, we described the initial clinical presentations, upper gastrointestinal endoscopic appearances, clinical follow-up, and histologic diagnoses in 7 patients who were subsequently diagnosed with Cronkhite-Canada syndrome. Histology slides were reviewed, and IgG4 immunohistochemical analysis was performed. The most common initial endoscopic impressions were antral malignancy and gastric infection, but gastroduodenal polyposis was not described. On histologic review, the main findings in the gastric mucosa were a prominent mucosal edema, a mixed inflammatory infiltrate rich in eosinophils, and architectural changes with gland dilatation and withering. In the duodenal mucosa, total or subtotal duodenal villous atrophy, inflammation, crypt distortion, and increased apoptotic bodies were the most common features. Three patients died of the disease, and 4 patients were asymptomatic at a mean follow-up of 3.5 years. No intestinal malignancy had been diagnosed. In 2 patients foci of dysplasia in colonic polyps were identified. In only 1 patient, a significant increase in IgG4-positive plasma cells was observed in a colonic polyp. In summary, we found that patients with Cronkhite-Canada syndrome have histologic features commonly found in other immune disorders of the gastrointestinal tract that may help in establishing the diagnosis and further supports the hypothesis that Cronkhite-Canada syndrome may represent an immune dysregulation syndrome, different from IgG4-related disease.

Microscopic colitis with giant cells: a clinico-pathological review of 11 cases and comparison with microscopic colitis without giant cells

Aim: To document clinical and pathological features of microscopic colitis with giant cells (MCGC) which is one of a number of atypical variants of microscopic colitis. Methods: Cases of microscopic colitis were assessed for giant cells during routine reporting and retrieved from the slide file at a private laboratory. The histological features and clinical data were assessed. Histochemistry (trichome and haematoxylin van Gieson) and immunohistochemistry (CD68) was performed to characterise the nature of the giant cells. Results: Giant cells were identified in 11 cases of microscopic colitis. The histological features of MCGC are not significantly different from usual MC except for the presence of multinucleated giant cells in the superficial lamina propria. Apart from the common but not unexpected association with autoimmune disease, no unique clinical features of the MCGC group were identified versus those described in the literature for ordinary MC. Immune disorders included gluten‐sensitive enteropathy, systemic lupus erythematosus and raised titres of antinuclear antibodies. Conclusions: The giant cells have the same immunohistochemical characteristics as histiocytes and appear to form through histiocyte fusion. The presence of giant cells does not appear to confer any further clinical significance and remains a histological curiosity.

Neutrophilic infiltration in gluten-sensitive enteropathy is neither uncommon nor insignificant: assessment of duodenal biopsies from 267 pediatric and adult patients.

The histologic findings of celiac disease, that is, gluten-sensitive enteropathy (GSE), are dominated by increased intraepithelial lymphocytes, villous blunting, lymphoplasmacytic infiltration of lamina propria, and crypt hyperplasia. To date, neutrophils have not been thought to constitute a significant cell type in GSE, and their presence often invokes consideration of alternative diagnoses. Thus, we sought to determine the prevalence and severity of neutrophilic infiltration in duodenal biopsies from patients with GSE. The degree of neutrophilic infiltration and features characteristic of GSE were assessed in duodenal biopsies from 267 clinically confirmed GSE patients (116 adults and 151 children). These specimens were graded by the disease activity score (DAS) and the neutrophilic activity score (NAS). Gastric antral biopsies obtained from 195 patients were also evaluated for lymphocytic gastritis. NAS was correlated with DAS and other clinicopathologic features. We found that 56% of pediatric and 28% of adult GSE patients had significant duodenal neutrophilia. NAS was higher in children than in adults (2.3 vs. 1.2, P<0.001). Multivariate regression showed that DAS, eosinophilic infiltration, and foveolar metaplasia correlated positively, and age correlated negatively with NAS. Lymphocytic gastritis was seen in 21.5% of the gastric biopsies. The presence of lymphocytic gastritis correlated positively with NAS and DAS, and in the pediatric population it correlated negatively with age. Significant duodenal neutrophilia is often found in patients with celiac disease, especially in the pediatric population, and is associated with more active disease. Thus, the findings of duodenal neutrophilia in biopsies, otherwise consistent with GSE, should not preclude the diagnosis of GSE.