Tumor regression grading after neoadjuvant treatment of esophageal and gastroesophageal junction adenocarcinoma: results of an international Delphi consensus survey.

Complete histopathologic tumor regression after neoadjuvant treatment is a well-known prognostic factor for survival among patients with adenocarcinomas of the esophagus and gastroesophageal junction. The aim of this international Delphi survey was to reach a consensus regarding the most useful tumor regression grading (TRG) system that could represent an international standard for histopathologic TRG grading of gastroesophageal carcinomas. Fifteen pathologists with special interest in esophageal and gastric pathology participated in the online survey. The initial questionnaire contained of 43 statements that addressed the following topics: (1) specimen processing, (2) gross examination, (3) cross sectioning, (4) staining, (5) Barrett's esophagus, (6) TRG systems, and (7) TRG in lymph node (LN). Participants rated the items using a 5-point Likert style scale and were encouraged to write comments for each statement. The expert panel recommended a 4-tiered TRG system for assessing the primary tumor: grade 1: No residual tumor (complete histopathologic tumor regression), grade 2: less than 10% residual tumor (near-complete regression), grade 3: 10%-50% residual tumor (partial regression), grade 4: greater than 50% residual tumor (minimal/no regression), combined with a 3-tiered system for grading therapeutic response in metastatic LNs: grade a: no residual tumor (complete histopathologic TRG), grade b: partial regression (tumor cells and regression), grade c: no regression (no sign of tumor response). This TRG grading system can be recommended as an international standard for histopathologic TRG grading in esophageal and gastroesophageal junction adenocarcinoma.

Diagnostic difficulties in inflammatory bowel disease pathology.

This review summarizes some of the common diagnostic problems encountered by pathologists when evaluating patients with chronic colitis and in whom inflammatory bowel disease (IBD) is either suspected or within the differential diagnosis. Both ulcerative colitis (UC) and Crohn's disease (CD) show characteristic, but non-specific, pathological features that may overlap and result in a diagnosis of 'indeterminate colitis' (IC). However, other reasons why pathologists may entertain a diagnosis of IC include failure to recognize or accept certain 'hardcore' histological features as indicative of CD, an attempt to classify cases of chronic colitis based on mucosal biopsy material or in the absence of adequate clinical and radiographic information, and the presence of other disease processes that mask, or mimic, IBD. In addition, some cases of UC may show unusual CD-like features, such as discontinuous or patchy disease, ileal inflammation, extracolonic inflammation, granulomatous inflammation in response to ruptured crypts, aphthous ulcers, or transmural inflammation. Furthermore, other forms of colitis, such as microscopic colitis, diverticulitis and diversion colitis may, on occasion, also show IBD-like changes. The clinical and pathological features that aid in the distinction between these entities, and others, are covered in detail in this review.

Hyperplastic polyp with epithelial misplacement (inverted hyperplastic polyp): a clinicopathologic and immunohistochemical study of 19 cases.

Hyperplastic polyps of the colon are the most common type of benign colonic polyp. Rarely, these polyps may show misplaced epithelium within the submucosa, thereby simulating an adenoma with pseudoinvasion or even an adenocarcinoma. In this study, we describe the clinical, pathologic, and immunophenotypic features of 19 hyperplastic polyps with misplaced epithelium to identify potential diagnostic pitfalls and gain insight into their pathogenesis. Routinely processed polypectomy specimens from 12 patients with 19 hyperplastic polyps containing foci of misplaced epithelium were evaluated for a variety of morphologic features including pattern and extent of submucosal involvement, continuity of the submucosal epithelium with the mucosa, presence of recent or remote hemorrhage, inflammation, association of misplaced epithelium with lymphoid aggregates, inflammation, and defects in the muscularis mucosae. Clinical and endoscopic data were obtained and correlated with the histologic findings. Immunoperoxidase stains (ABC method) for collagen IV (basement membrane marker), MIB-1 (proliferation marker), and E-cadherin (intercellular adhesion protein) were performed in all cases. The study group consisted of five males and seven females ranging in age from to 52 to 73 years (mean: 63 y). All of the polyps were located in the rectum or sigmoid colon, and their mean size was 0.5 cm (range: 0.2 to 1.0 cm). Most showed misplaced epithelium in a lobular (26%) or a mixed pattern consisting of lobules and irregularly distributed crypts (63%) that, upon deeper levels, was almost always continuous with the mucosal portion of the polyps (95%). Defects in the muscularis mucosae and splaying of the muscle fibers around misplaced epithelium were seen in all cases. Lymphoid aggregates were present adjacent to foci of misplaced epithelium in 37% of cases. Fresh hemorrhage, vascular congestion, and hemosiderin deposits were present in 79, 53, and 42% of cases, respectively. Strong and uniform staining of the misplaced epithelium for MIB-1 and E-cadherin was demonstrated in all cases, similar to that seen in the lower third of the mucosal portion of the polyps. A continuous collagen IV basement membrane pattern of staining was noted around all foci of misplaced epithelium. Hyperplastic polyps with misplaced epithelium probably occur secondary to trauma-induced protrusion of glands through breaks in the muscularis mucosae. Pathologists should be aware of this entity to avoid diagnostic confusion with other, more serious lesions, such as adenomas with pseudoinvasion or well-differentiated adenocarcinoma.

Endometriosis of the intestinal tract: a study of 44 cases of a disease that may cause diverse challenges in clinical and pathologic evaluation.

Endometriosis of the intestinal tract may mimic a number of diseases both clinically and pathologically. The authors evaluated 44 cases of intestinal endometriosis in which endometriosis was the primary pathologic diagnosis, and evaluated them for a variety of gross and histologic changes. Cases with preneoplastic or neoplastic changes were excluded specifically because they were the subject of a previous study. The patients ranged in age from 28 to 56 years (mean age, 44 years), and presenting complaints included abdominal pain (n = 15), an abdominal mass (n = 12), obstruction (n = 8), rectal bleeding (n = 2), infertility (n = 3), diarrhea (n = 2), and increasing urinary frequency (n = 1). The clinical differential diagnoses included diverticulitis, appendicitis, Crohn's disease, tubo-ovarian abscess, irritable bowel syndrome, carcinoma, and lymphoma. Forty-two patients underwent resection of the diseased intestine and two patients underwent endoscopic biopsies. In 13 patients there were predominantly mural masses, which were multiple in two patients (mean size, 2.6 cm). In addition, 11 cases had luminal stenosis or strictures, six had mucosal polyps, four had submucosal masses that ulcerated the mucosa (sometimes simulating carcinoma), three had serosal adhesions, one had deep fissures in the mucosa, and one was associated with appendiceal intussusception. Involvement of the lamina propria or submucosa was identified in 29 cases (66%) and, of these, 19 had features of chronic injury including architectural distortion (n = 19), dense lymphoplasmacytic infiltrates (n = 7), pyloric metaplasia of the ileum (n = 1), and fissures (n = 1). Three cases had features of mucosal prolapse (7%), ischemic changes were seen in four (9%), and segmental acute colitis and ulceration were seen in four and six cases (9% and 13%) respectively. In 14 patients, endometriosis formed irregular congeries of glands involving the intestinal surface epithelium, mimicking adenomatous changes. Mural changes included marked concentric smooth muscle hyperplasia and hypertrophy, neuronal hypertrophy and hyperplasia, and fibrosis of the muscularis propria with serositis. Follow-up of 20 patients (range, 1-30 years; mean, 7.8 years) revealed that only two patients had recurrent symptoms. None of the patients developed inflammatory bowel disease. Endometriosis can involve the intestinal tract extensively, causing a variety of clinical symptoms, and can result in a spectrum of mucosal alterations. Because the endometriotic foci may be inaccessible to endoscopic biopsy or may not be sampled because of their focality, clinicians and pathologists should be aware of the potential of this condition to mimic other intestinal diseases.

Pathology residents' use of a Web-based tutorial to improve Gleason grading of prostate carcinoma on needle biopsies.

Little is known about pathology residents' ability to Gleason grade or their ability to learn surgical pathology using Internet-based technology. A free Web-based program (available at www.pathology. jhu.edu/prostate) was developed that consisted of 20 pretutorial images for grading, 24 tutorial images, and the same 20 posttutorial images for Gleason grading. The grading images were selected from cases that had a consensus Gleason grade from 10 uropathology experts. In 2.5 months, 255 residents visited the website, and 151 (59%) completed it. Of those who completed the website, their year in training was known in 85 (56%): 1st year, 25.8%; 2nd year, 20%; 3rd year, 22.3%; 4th year, 14.1%; 5th year, 15.3%; and 6th year, 2.4%. Eighty percent learned Gleason grading in residency versus being self-taught, and 66% were male. In a multivariate analysis, higher pretutorial scores were associated with both their year in training (P = .001) and their hospital size (P = .003). Improvements in grading posttutorial were not related to the residents' year in training. Overall, the website significantly improved grading in 11 of 20 images and had no effect in 9 of 20 images. Improvements were noted in 1 of 1 Gleason score 4; 2 of 7 Gleason score 5 to 6; 2 of 6 Gleason score 7; and 6 of 6 Gleason score above 7 tumors. In summary, a Web-based tutorial improved Gleason grading accuracy by pathology residents to an equal extent regardless of their year in training. It is more difficult to teach residents to grade Gleason scores 5 to 7 tumors, and additional training should be concentrated in this area.

Lipid-rich diffuse malignant mesothelioma: a case report.

An 80-year old man presented with shortness of breath and was found to have a large right pleural effusion. Cytology of the pleural fluid showed atypical papillary clusters of epithelioid cells. Multiple white-yellow nodules studding the pleural surfaces were seen at thoracoscopy, and biopsies showed solid and papillary clusters of large epithelioid cells with abundant cytoplasm filled with clear vacuoles. Special stains and electron microscopic findings indicated that the tumor was a diffuse malignant mesothelioma with numerous intracytoplasmic lipid vacuoles. Fat stain may be useful at time of frozen section for a pleural-based tumor with vacuolated cells, and the presence of lipid vacuoles in a pleural-based tumor does not exclude diffuse malignant mesothelioma.

Gastrointestinal stromal tumor versus intra-abdominal fibromatosis of the bowel wall: a clinically important differential diagnosis.

Intra-abdominal fibromatosis (IAF) is an uncommon benign neoplasm that usually occurs in the mesentery or retroperitoneum and may, on occasion, mimic a gastrointestinal stromal tumor (GIST). Differentiating between these two entities is important clinically because IAF is a benign tumor whereas GISTs frequently have malignant potential. In this study, the authors identified 13 cases of IAF with prominent involvement of the bowel wall as well as 35 GISTs of the small intestine, colon, or mesentery and analyzed their clinical, gross, histologic, immunophenotypic, and ultrastructural characteristics to identify important distinguishing features. Patients with IAF were younger (mean, 34 yrs) than patients with GIST (mean, 54 yrs). Both types of tumors tended to be large, but GISTs were soft and lobulated with hemorrhage, necrosis, or cystification whereas IAFs were firm, tan, and homogeneous. Histologic features characteristic of GIST included the presence of spindle or epithelioid cells with variable architecture, mitotic activity (range, <1-95 mitoses/50 high-power fields [hpf]; mean, 15 mitoses/50 hpf), nuclear atypia, and myxoid or hyalinized stroma. Necrosis and hemorrhage were seen in 16 and 25 tumors, respectively. In contrast, IAFs were composed of broad, sweeping fascicles of monotonous spindle cells with mitotic activity (range, <3-11 mitoses/50 hpf; mean, 4 mitoses/50 hpf), bland nuclear features, and finely collagenous stroma. Necrosis, hemorrhage, and myxoid degeneration were not seen. Immunohistochemical studies performed on a limited number of GISTs and IAFs demonstrated that cells expressed vimentin (100% GIST and IAF), CD117 (88% GIST and 75% IAF), CD34 (42% GIST and 0% IAF), smooth muscle actin (63% GIST and 75% IAF), muscle actin (75% GIST and 75% IAF), desmin (8% GIST and 50% IAF), and S-100 protein (16% GIST and 0% IAF). Ultrastructural analysis of 21 GISTs revealed incomplete smooth muscle differentiation in some tumors whereas IAFs were shown to have complete myofibroblastic/fibroblastic differentiation. Information regarding clinical outcome was available on 29 patients and revealed that three patients with histologically benign GISTs were alive with no evidence of disease at 5 months to 6 years (mean, 3.5 yrs) and one patient with a histologically benign tumor died of disease after 7 years. Of patients with histologically malignant GIST, one died of surgical complications, 10 were alive without disease at I to 13 years (mean, 5.4 yrs), four were alive with disease at 4 months to 15 years (mean, 3.8 yrs), three had disseminated disease at operation, and seven were dead of disease at 10 months to 3 years (mean, 2.2 yrs). Follow up of eight patients with IAF demonstrated that five were alive without disease at 4 months to 15 years (mean, 5.3 yrs) and three had recurrences at 1 (two patients) and 2 years (one patient). In summary, IAFs can have many features (large size, infiltration of adjacent structures, mitotic activity) that can cause diagnostic confusion with GISTs and, importantly, the degree of mitotic activity present in IAFs may overlap that seen in malignant GISTs. These entities can be distinguished primarily by their light microscopic and ultrastructural features but there is a notable overlap in their immunohistochemical profiles. The distinction between these neoplasms is important because there are important clinical implications for the patient.

Neoplastic and pre-neoplastic changes in gastrointestinal endometriosis: a study of 17 cases.

The clinicopathologic features of neoplasms arising in gastrointestinal endometriosis have not been well characterized. In this series, we report 17 cases of gastrointestinal endometriosis complicated by neoplasms (14 cases) or precancerous changes (three cases). Four patients, one of whom also had hypermenorrhea, presented with chronic abdominal pain and five had obstructive symptoms; one of these also had rectal bleeding. One patient presented with an acute abdomen and fecal peritonitis, one had vaginal bleeding, and one had a progressive change in bowel habits. Nine patients had a long history of endometriosis, 11 patients had had hysterectomies, and eight of these had also received unopposed estrogen therapy. The lesions involved the rectum (6), sigmoid (6), colon, unspecified (2), and small intestine (3), and comprised 8 endometrioid adenocarcinomas (EA), 4 mullerian adenosarcomas (MAS), 1 endometrioid stromal sarcoma (ESS), 1 endometrioid adenofibroma of borderline malignancy (EBA) with carcinoma in situ, 2 atypical hyperplasias (AH), and one endometrioid adenocarcinoma in situ (ACIS). The tumors ranged in size from 2 to 15 cm and all involved the serosa and muscularis propria. Two tumors extended into the mucosa, with mucosal ulceration in one. Follow-up was available in 11 cases. One patient with EA was dead of disease at 1 year, one had two recurrences at 1 and 2 years, and three were alive with no evidence of disease (ANED) at 9 months to 13 years (mean, 68 mos). The patient with the EBA was ANED at 3 months. Two patients with MAS were ANED at 2 and 3 years. The patient with ESS had a recurrence at 3 years and was ANED 6 years after her original diagnosis. One woman with AH was ANED at 60 months and the patient with ACIS was ANED at 16 months. One of the carcinomas was originally misdiagnosed as a primary intestinal adenocarcinoma. The pathologist should be aware of the possibility of a tumor of genital tract type when evaluating intestinal neoplasms in females, particularly if they have a history of endometriosis and have received unopposed estrogen therapy.

Mucinous adenocarcinoma of the parotid gland. Report of a case with fine needle aspiration findings and histologic correlation.

BACKGROUND: Mucinous adenocarcinoma rarely arises as a primary tumor within the parotid gland, and only the histologic features of this tumor have been described. CASE: A 4-cm, firm mass arose in the right parotid gland of a 72-year-old male over a six-week period. Cystic on computed tomography, the mass, on fine needle aspiration biopsy, yielded monomorphic, moderately atypical cells, both single and clustered, associated with abundant mucoid material and focal necrosis. Tumor cells had eccentric nuclei, prominent nucleoli and occasional cytoplasmic vacuolization. A few binucleated and multinucleated tumor cells were present. Histologic sections of the resected gland showed mucinous adenocarcinoma. A metastatic workup was negative. The differential diagnoses on cytology included other primary tumors of the parotid gland producing mucin or a mucoid matrix and metastatic mucinous adenocarcinomas. CONCLUSION: To our knowledge, this is the first cytologic description of mucinous adenocarcinoma, primary in the parotid gland.

MR lymphangiography using ultrasmall superparamagnetic iron oxide in patients with primary abdominal and pelvic malignancies: radiographic-pathologic correlation.

OBJECTIVE: The purpose of this study was to administer ultrasmall superparamagnetic iron oxide (USPIO) and compare changes in signal intensity of lymph nodes in patients with primary abdominal and pelvic malignancies. Also, we correlated radiographic with pathologic findings. SUBJECTS AND METHODS: Nineteen patients with proven primary abdominal or pelvic cancer (prostatic [n = 10]; colonic [n = 5]; endometrial [n = 1]; Merkel cell tumor [n = 1]; lymphoma [n = 1]; seminoma [n = 1]) were enrolled as part of our phase II and phase III clinical trials. In these patients, 49 lymph nodes (mean size, 1.4 cm) revealed on CT or MR imaging were evaluated on T1-weighted spin-echo, T2-weighted fast spin-echo, and T2*-weighted gradient-echo MR imaging at 1.5 T 24-36 hr after IV administration of USPIO. Quantitative analyses used measurements of unenhanced and enhanced region-of-interest values in lymph nodes. Qualitative assessment used subjective evaluation and classification of changes in signal intensity. All patients underwent lymph node biopsy or surgical dissection followed by histopathologic correlation. RESULTS: Of the 49 lymph nodes that were evaluated, 20 were benign and 29 were malignant. A decrease in nodal signal intensity on enhanced T2-weighted and T2*-weighted gradient-echo images was seen in 20 benign lymph nodes and two malignant lymph nodes. No appreciable signal change was noted in 27 of the 29 malignant lymph nodes. The mean signal intensity on fast spin-echo T2-weighted images for benign lymph nodes changed from 186.48 (unenhanced) to 73.66 (enhanced). Conversely, mean signal intensity for malignant lymph nodes was relatively unchanged from 191.17 (unenhanced) to 183.18 (enhanced). CONCLUSION: USPIO appears to be a useful MR contrast agent for characterizing benign and malignant lymph nodes based on the enhancement criteria evaluated in our study.