Amirkaveh Mojtahed

HER2 expression in gastric and gastroesophageal junction adenocarcinoma in a US population: clinicopathologic analysis with proposed approach to HER2 assessment.

Recent evidence suggests that trastuzumab, a monoclonal antibody which targets HER2, in combination with chemotherapy is a therapeutic option in patients with HER2-positive gastric or gastroesophageal junction cancer. Widely accepted guidelines for HER2 testing in gastric and gastroesophageal junction cancer have not been established. The purpose of this study was to analyze the incidence and patterns of HER2 expression in gastric and gastroesophageal junction cancer using a tissue microarray approach, which closely simulates small biopsies routinely tested for HER2. One hundred sixty-nine patients, including 99 primary gastric adenocarcinomas and 70 primary gastroesophageal junction carcinomas were analyzed for HER2 overexpression by immunohistochemistry and HER2 gene amplification by fluorescence in situ hybridization using scoring schemes proposed by both American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) and the results of the recently published Trastuzumab for Gastric Cancer (ToGA) trial. In our analysis, 19 adenocarcinomas were HER2 positive, defined as either a HER2/CEP17 ratio >2.2 and/or a 3+ HER2 immunohistochemistry score with either the ASCO/CAP or ToGA scoring schemes. Of the 19 HER2-positive adenocarcinomas, 8 (42%) exhibited a characteristic strongly intense basolateral membranous staining pattern which would be interpreted as negative (1+) using the accepted ASCO/CAP scoring scheme for HER2 assessment in breast carcinoma, but were correctly labeled as 3+ positive using the proposed ToGA scoring scheme. Of the 19 HER2-positive adenocarcinomas, 8 (42%) demonstrated heterogeneous HER2 protein expression by immunohistochemistry. Twelve of 99 (12%) gastric carcinomas were positive for HER2. Of these, HER2 was more often identified in intestinal-type adenocarcinomas (10 of 52, 19%) compared with diffuse (2 of 34, 6%) adenocarcinoma. Seven of 70 (10%) gastroesophageal junction carcinomas were positive for HER2 of which all were intestinal type (7 of 58, 12%). HER2 status or primary tumor site did not correlate with patient survival. Gastric and gastroesophageal junction adenocarcinomas typically display a characteristic basolateral membranous pattern of HER2 expression which is often heterogeneous rendering routine evaluation of HER2 status on small tissue samples challenging.

A two-antibody mismatch repair protein immunohistochemistry screening approach for colorectal carcinomas, skin sebaceous tumors, and gynecologic tract carcinomas.

Mismatch repair protein immunohistochemistry is a widely used method for detecting patients at risk for Lynch syndrome. Recent data suggest that a two-antibody panel approach using PMS2 and MSH6 is an effective screening protocol for colorectal carcinoma, but there are limited data concerning this approach for extraintestinal tumors. The purpose of this study was to review the utility of a two-antibody panel approach in colorectal carcinoma and extraintestinal tumors. We evaluated mismatch repair protein expression in two cohorts: (1) a retrospective analysis of intestinal and extraintestinal tumors (n=334) tested for mismatch repair protein immunohistochemistry and (2) a prospectively accrued series of intestinal, gynecologic tract, and skin sebaceous neoplasms (n=98). A total of 432 cases were analyzed, including 323 colorectal, 50 gynecologic tract, 49 skin sebaceous, and 10 other neoplasms. Overall, 102/432 tumors (24%) demonstrated loss of at least one mismatch repair protein. Concurrent loss of MLH1 and PMS2 was the most common pattern of abnormal expression (50/432, 12%) followed by concurrent loss of MSH2 and MSH6 (33/432, 8%). Of 55 cases with abnormal PMS2 expression, 5 (9%) demonstrated isolated loss of PMS2 expression. Of 47 cases with abnormal MSH6 expression, 14 (30%) demonstrated isolated loss of MSH6 expression. Isolated loss of MLH1 or MSH2 was not observed. Colorectal carcinomas more frequently demonstrated abnormal expression of PMS2 (39/59, 66%). Skin sebaceous neoplasms more frequently demonstrated abnormal expression of MSH6 (18/24, 75%, respectively). A total of 65 tumors with abnormal mismatch repair protein expression were tested for microsatellite instability (MSI): 47 (72%) MSI high, 9 (14%) MSI low, and 9 (14%) microsatellite stable (MSS). Abnormal MSH6 expression accounted for 14/18 (78%) cases that were MSS or MSI low. Our findings confirm the utility of a two-antibody approach using PMS2 and MSH6 in colorectal carcinoma and indicate that this approach is effective in extraintestinal neoplasms associated with Lynch syndrome.

Histologic and molecular analyses of colonic perineurial-like proliferations in serrated polyps: perineurial-like stromal proliferations are seen in sessile serrated adenomas.

Colonic perineuriomas are recently described benign mucosal polyps that are composed of a bland spindle cell proliferation surrounding crypts that often demonstrate hyperplastic/serrated epithelial changes. However, the origin of this unique stromal proliferation is still unclear, and the association with serrated polyps, including sessile serrated adenomas, has not been fully described. We evaluated the pathologic and molecular features of colonic polyps associated with perineurial-like proliferations in 2 retrospective cohorts: (1) a series of 198 consecutive sessile serrated adenomas and (2) 20 colonic polyps diagnosed as a perineurioma irrespective of the presence of serrated colonic crypts. Thirteen of 198 (6.5%) sessile serrated adenomas demonstrated a perineurial-like stromal proliferation, with most (12 of 13, 92%) involving the right (9 cases) and transverse colon (3 cases). In all 13 cases, the perineurial-like proliferation surrounded serrated colonic crypts and typically involved only a small area of the sessile serrated adenoma (average 9% of polyp size; range, 2% to 19%). All 11 polyps evaluated for epithelial membrane antigen (EMA) expression demonstrated stromal EMA staining limited to the perineurial-like proliferation. Twelve of 13 (92%) sessile serrated adenomas with perineurial-like proliferations demonstrated a pV600E BRAF mutation. Of the 20 colonic polyps diagnosed as a perineurioma, 18 (90%) demonstrated serrated crypts intimately associated with the perineurial-like proliferation. In 13 of 18 polyps with associated serrated crypts, all serrated crypts were invested with the perineurial proliferation. In 5 cases, serrated crypts were seen away from the perineurial proliferation. Of these 18 polyps, the majority (16 of 18, 89%) were microvesicular hyperplastic polyps involving the left colon. However, 2 (11%) polyps in the right colon demonstrated histologic features diagnostic of sessile serrated adenoma. All 18 polyps with serrated crypts demonstrated a pV600E BRAF mutation. In contrast, the 2 polyps not associated with serrated crypts were negative for a BRAF mutation. Our results show for the first time that perineurial-like stromal proliferations frequently occur in sessile serrated adenomas. The presence of focal perineurial-like stromal proliferations in sessile serrated adenomas and the common finding of serrated crypts in colonic perineuriomas are likely indicative of an epithelial-stromal interaction, possibly related to some factor elaborated by the serrated epithelium.

Relapse of intestinal and hepatic amebiasis after treatment.

Six months after returning from a trip to Hawaii, a previously healthy 63-year-old man presented with 5 months of right upper-quadrant abdominal pain and non-bloody diarrhea, 3 months of nausea and non-bloody vomiting, and 1 month of fevers, chills, night sweats, and anorexia, culminating in a loss of 20 lbs. Comprehensive laboratory tests were notable for leukocytosis with a white blood cell (WBC) count of 11,300/mm with 88% neutrophils, elevated liver chemistry tests (total bilirubin 0.6 mg/dl, aspartate aminotransferase [AST] 64 U/l, alanine aminotransferase [ALT] 92 U/l, and alkaline phosphatase 674 U/l), and renal failure (blood urea nitrogen 57 mg/dl, creatinine 2.3 mg/dl). Due to his renal insufficiency, non-contrast imaging of the abdomen was obtained, which revealed a 12-cm, thick-walled, multiloculated cystic lesion in the right lobe of the liver (Fig. 1a). Cultures obtained from the patient’s blood, stool, and fluid aspirated from the liver abscess remained sterile. However, serum antibodies to Entamoeba histolytica were positive at a titer of 1:128. The infection was reported to the Department of Health who corroborated the diagnosis with three other cases of Entamoeba histolytica infection that were traced back to a restaurant worker in Hawaii. The patient was treated with oral metronidazole 750 mg three times daily for 10 days, followed by oral paromomycin 1 g three times daily for 10 days. His abdominal pain and diarrhea resolved. A contrast-enhanced abdominal computed tomography (CT) scan, obtained 2 months after finishing his course of antibiotics, documented complete resolution of the liver abscess (Fig. 1b). One year later, the patient again presented with fevers, chills, fatigue, abdominal pain, and diarrhea for 1 month, but this time also reported melena and maroon-colored stools for 1 week. His abdominal pain originated in the epigastrium, radiated to the right upper quadrant, and worsened when lying on his right side. On retrospection, he noted that he had suffered from diarrhea intermittently since his admission the previous year, but each episode had resolved with loperamide. He denied any weight loss and had actually regained 30 lbs. since discharge. He had not traveled anywhere since returning from Hawaii and could not recall any sick contacts. On physical examination, he had a low-grade fever to 100.2 F, but his vitals were otherwise normal. In general, he was well-appearing and without jaundice. He had normal bowel sounds, but his abdomen was distended and mild tenderness could be elicited upon palpation of the epigastrium, right upper-quadrant and right lower-quadrant of the abdomen. He had heme-positive, black-colored stool on rectal examination. Laboratory testing again revealed leukocytosis (WBC 9,500 with 80% neutrophils) and abnormal liver chemistry tests (total bilirubin\0.5 mg/dl, AST 33 U/l, ALT 39 U/l, and alkaline phosphatase 212 U/l). A contrast-enhanced CT of the abdomen showed a 6.0 9 5.2-cm hypo-attenuating mass in segment 4 of the liver with adjacent hyperemia and E. W. Hwang (&) C. A. Cartwright Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University Medical Center, 300 Pasteur Drive, Alway Building, M211, Stanford, CA 94305-5187, USA e-mail: ehwang@stanford.edu

Reactive lymphoid hyperplasia of the terminal ileum: a benign (lymphoma-like) condition that may harbor aberrant immunohistochemical patterns or clonal immunoglobulin heavy chain gene rearrangements.

Small endoscopic biopsies of the terminal ileum may be difficult to assess for early involvement by lymphoma. Immunophenotypic and genotypic analyses are often utilized, but the performance of these studies in this setting is not well defined. Terminal ileal biopsies from 66 patients with prominent lymphoid hyperplasia and abnormal “lymphoma-like” morphology were evaluated by immunohistochemistry (IHC) for CD3, CD5, CD43, CD20, CD21, and CD10 expression and for IGH@ gene rearrangement by polymerase chain reaction using BIOMED-2 primers. Patients ranged in age from 3 to 80 years. Indications for endoscopy included inflammatory bowel disease (29), diarrhea and/or abdominal pain (28), history of lymphoma (13), and others (4). Four biopsies with abnormal morphology had abnormal IHC and a clonal IGH@ peak; all were obtained from patients with a history of lymphoma and determined to be recurrent lymphoma. Three biopsies with abnormal morphology and abnormal IHC but no clonal IGH@ peak were obtained from patients with a history of lymphoma (2) and chronic diarrhea (1); all showed symptom resolution or remission of disease (mean follow-up, 37 mo). Eight biopsies with abnormal morphology but no abnormal IHC expression also had abnormal IGH@ results (4 clonal and 4 borderline). IGH@ evaluation of follow-up biopsies for these cases were nonclonal (7) or clonal, but with a different clone from the prior biopsy (1); follow-up of the 8 patients showed no evidence of lymphoma (mean, 37.8 mo). Abnormal IHC expression pattern or clonal IGH@ rearrangement in endoscopic biopsies of the lymphoid-rich terminal ileum do not necessarily warrant a diagnosis of lymphoma. To prevent misdiagnosis, B-cell clonality studies should only be performed when there is strong clinical suspicion for lymphoma and compelling IHC data; the absence of a reproducible clone in repeat biopsy specimens may be useful in patients that do not have other clinical evidence of lymphoma.

Acute Liver Failure and Aplastic Anemia in an 11-Year-Old Girl

An 11-year-old previously healthy female presented with a 1-week history of jaundice and fatigue. Her aspartate aminotransferase (AST) level was 1,420 U/L, alanine aminotransferase (ALT) 1,044 U/L, total bilirubin 16.5 mg/dL and international normalized ratio (INR) for prothrombin time 1.2. Complete blood count showed a white blood count of 7,700/mm, hematocrit 40.6 g/dL, and platelet count 509,000/mm. Ultrasound demonstrated mild hepatomegaly but was otherwise normal. Serology was negative for hepatitis A, B, and C and Epstein-Barr virus (EBV) and cytomegalovirus (CMV). After discharge, she was followed by her outpatient pediatric gastroenterologist, who noted that she continued to have jaundice and elevated aminotransferase levels. A liver biopsy was recommended, but her parents refused, and the patient was lost to followup for several months. Four months after her initial presentation, the patient represented with a 2-week history of sleepiness, headaches, increased jaundice, and anorexia. During the time she was lost to follow-up, her parents noted an initial improvement of her jaundice and energy. However, 2 weeks prior to her readmission, she had increasing fatigue, jaundice, and epistaxis. Complete blood count revealed a WBC of 2.3 g/mm, hematocrit 33.2 g/dL, and platelet count 13,000/mm. Total bilirubin was 21.8 mg/dL, direct bilirubin 14.6 mg/dL, AST 3,158 U/L, ALT 3,239 U/L, INR 2.0, erythrocyte sedimentation rate 16, C-reactive protein 23 mg/dL, and ammonia 38 lm/L. She was admitted for lethargy in the setting of liver failure and pancytopenia. On admission to the hospital, her vital signs were normal and physical examination revealed an alert, interactive female with marked jaundice. Lungs were clear to auscultation, and heart tones were regular with no murmurs. Her abdomen was soft, nontender and not distended; her liver was palpated 2 cm below the right costal margin, and the spleen tip was palpated 3 cm below the left costal margin. Ultrasound of the abdomen showed mild hepatomegaly and thickened gallbladder wall with no sludge or stones. She was listed for liver transplantation, and began transfusion therapy with fresh frozen plasma and platelets as needed for procedures. Further blood tests showed negative human immunodeficiency virus (HIV) antibody, CMV polymerase chain reaction (PCR), and EBV PCR. Her alpha-1-antitrypsin level was normal, anti liver-kidney microsome antibody negative, antismooth muscle antibody negative, antinuclear antibody negative, drug screen for urine and serum negative, varicella immunoglobulin (Ig)G negative with an equivocal IgM. Ophthalmology consultation was negative for ocular abnormalities and Kayser-Fleischer rings, and her serum ceruloplasmin was 29 mg/dL. A 24-h urine collection for copper was 260 mcg/specimen (normal, less than 60), but the reliability of this test was questioned given that the patient had 4 L of urine collected while receiving furosemide. A magnetic resonance cholangiopancreatography (MRCP) showed no biliary stones or biliary dilatation, a mildly enlarged liver and spleen, thickened gallbladder wall, pericholecystic fluid, trace bilateral pleural effusions, and A. M. Yeh D. Bass (&) Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Stanford University Medical Center, Lucile Packard Children’s Hospital at Stanford, 750 Welch Road, Suite 116, Palo Alto, CA 94304-0126, USA e-mail: dmbass@stanford.edu

Acute Liver Failure in a Pediatric Patient with Disseminated Tuberculosis

A seven-year-old male presented to the emergency department of a local hospital with sudden onset of mental status changes and jaundice. He had previously been a healthy child who was born and spent his first years of his life in India. He had normal growth and development. He was fully immunized and had also received the Bacillus Calmette–Guérin (BCG) vaccine. His past and family medical history was unremarkable, with the exception that his mother had been successfully treated for isoniazid (INH)-resistant tuberculosis (TB) three years previously. At that time, the patient had 14 mm of induration after a tuberculin skin test, and he and other members of the household were treated for 9 months with rifampin. His chest X-ray remained normal. He had not been previously hospitalized or had any previous surgery. The patient and his family moved to California’s Central Valley several years before admission, and had not traveled since emigrating. The patient was an only child, and the family lived in a household with several healthy relatives and no pets. He was transferred to Stanford University Medical Center for potential liver transplantation. The patient first became ill two months before admission with the onset of abdominal pain and fever up to 40 C for six weeks. The cause of his fever was investigated on both an outpatient basis and during two inpatient admissions in the month that preceded transfer to Stanford University Medical Center. During the first admission, two possible diagnoses were pursued, including coccidiomycosis, because the patient resided in an endemic region, and TB, because of the patient’s previous known exposure. A chest X-ray revealed hilar and peritracheal lymphadenopathy. An abdominal computed tomography (CT) scan was normal. A tuberculin skin test was negative, as was a gastric aspirate for acid-fast bacilli (AFB). Stool cultures for bacteria and parasites, and antibody tests for coccidiomycosis were negative. The patient was discharged on empiric treatment for both TB and coccidiomycosis, including ceftriaxone, fluconazole, ethambutol, INH, pyrazinamide, pyridoxine, and rifampin. On examination during his second admission, the patient was noted to have hepatosplenomegaly. An echocardiogram revealed a small pericardial effusion. Multiple serum acid-fast bacillus (AFB) smears were negative, and bronchoalveolar lavage was negative for fungus, bacteria, and AFB. However, he was started on empiric treatment for TB and coccidiomycosis with rifampin, INH, pyrazinamide, ethambutol, and fluconazole before being transferred to Stanford. When the patient arrived in the intensive-care unit, he was febrile with normal vital signs. Physical examination revealed a cachectic, combative young male who was not oriented and not able to follow commands. His conjunctivae were icteric. His neurologic examination revealed J. Whitney (&) Stanford University School of Medicine, 291 Campus Drive, Stanford, CA 94305, USA e-mail: jane.whitney@stanford.edu