Michael A. DiMaio

Clinicopathologic and molecular features of sporadic early-onset colorectal adenocarcinoma: an adenocarcinoma with frequent signet ring cell differentiation, rectal and sigmoid involvement, and adverse morphologic features

Recent literature suggests an increasing incidence of colorectal carcinoma in young patients. We performed a histologic, molecular, and immunophenotypic analysis of patients with sporadic early-onset (≤40 years of age) colorectal carcinoma seen at our institution from the years 2000–2010 and compared these tumors to a cohort of consecutively resected colorectal carcinomas seen in patients >40 years of age. A total of 1160 primary colorectal adenocarcinomas were surgically resected for the years 2000 through 2010. Of these, 75 (6%) were diagnoses in patients ≤40 years of age of which 13 (17%) demonstrated abnormalities in DNA mismatch repair, 4 (5%) were in patients with known germline genetic disorders (two patients with familial adenomatous polyposis, one patient with juvenile polyposis, and one patient with Li-Fraumeni syndrome), and three patients (4%) had long-standing chronic inflammatory bowel disease. The sporadic early-onset colorectal carcinoma group comprised a total of 55 patients (55/1160, 5%) and were compared with a control group comprising 73 consecutively resected colorectal carcinomas with proficient DNA mismatch repair in patients >40 years of age. For the early-onset colorectal carcinoma group, most cases (33/55, 60%) were diagnosed between the age of 35 and 40 years of age. Compared with the control group, the early-onset colorectal carcinoma group was significantly different with respect to tumor location (P<0.007) with 80% (44/55 cases) identified in either the sigmoid colon (24/55, 44%) or rectum (20/55, 36%). Morphologically, early-onset colorectal carcinomas more frequently displayed adverse histologic features compared with the control colorectal carcinoma group such as signet ring cell differentiation (7/55, 13% vs 1/73, 1%, P=0.021), perineural invasion (16/55, 29% vs 8/73, 11%, P=0.009) and venous invasion (12/55, 22% vs 4/73, 6%, P=0.006). A precursor adenomatous lesion was less frequently identified in the early-onset colorectal carcinoma group compared with the control group (19/55, 35% vs 39/73, 53%, P=0.034). Of the early-onset colorectal carcinomas, only 2/45 cases (4%) demonstrated KRAS mutations compared with 11/73 (15%) of the control group colorectal adenocarcinomas harboring KRAS mutations, although this difference did not reach statistical significance (P=0.13). BRAF V600E mutations were not identified in the early-onset colorectal carcinoma group. No difference was identified between the two groups with regard to tumor stage, tumor size, number of lymph node metastases, lymphatic invasion, tumor budding, mucinous histology, or tumor-infiltrating lymphocytes. Both groups had similar recurrence-free (P=0.28) and overall survival (P=0.73). However, patients in the early-onset colorectal carcinoma group more frequently either presented with or developed metastatic disease during their disease course compared with the control colorectal carcinoma group (25/55, 45% vs 18/73, 25%, P=0.014). In addition, 8/55 patients (15%) in the early-onset colorectal carcinoma group developed local recurrence of their tumor while no patients in the control colorectal carcinoma group developed local recurrence (P<0.001), likely due to the increased incidence of rectal carcinoma in the patients with early-onset colorectal carcinoma. Our study demonstrates that colorectal carcinoma is not infrequently diagnosed in patients ≤40 years of age and is not frequently the result of underlying Lynch syndrome or associated with other cancer-predisposing genetic conditions or chronic inflammatory conditions. These tumors have a striking predilection for the distal colon, particularly the sigmoid colon and rectum and are much more likely to demonstrate adverse histologic factors, including signet ring cell differentiation, venous invasion, and perineural invasion.

Idelalisib-associated Enterocolitis: Clinicopathologic Features and Distinction From Other Enterocolitides.

Idelalisib is a highly specific small-molecule phosphoinositide-3-kinase &dgr; inhibitor that was recently approved by the Food and Drug Administration for the treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma and follicular lymphoma. The known side effects of idelalisib include severe diarrhea and colitis. Here we report the histologic findings in idelalisib-associated enterocolitis in 11 patients with chronic lymphocytic leukemia or follicular lymphoma receiving idelalisib over a 5-year period (2011 to 2015) at our institution. All 11 patients were receiving idelalisib and underwent colonoscopy for the evaluation of diarrhea. None of the patients had previously received a stem cell transplant. Histologically, the colon biopsies in all 11 cases showed some degree of apoptosis within crypts, with 5 cases showing moderate to severe apoptosis involving the majority of the crypts with loss of goblet cells. No viral inclusions were seen in any case and immunohistochemical stains for cytomegalovirus performed in 9/11 cases were negative. All cases showed at least focal acute cryptitis, and 8 of these cases showed mild architectural distortion. Increased inflammation within the lamina propria was seen in 7 cases, and increased intraepithelial lymphocytes within crypts was seen in 8 cases; the lymphocytes were mostly T cells with a predominance of CD8+ T cells, with the majority expressing the &agr;/&bgr; T-cell receptor. Diagnoses of graft-versus-host disease, autoimmune enteropathy, infectious enterocolitis, and although thought to be less likely, inflammatory bowel disease were considered in each case. The presence of numerous intraepithelial lymphocytes in addition to severe villous blunting and apoptosis in the small intestinal biopsies from a subset of these patients additionally raised the possibility of autoimmune enteropathy, common variable immunodeficiency, or less likely, celiac disease. Awareness of the histologic features of idelalisib-associated enterocolitis is important to distinguish it from potential mimics, particularly graft-versus-host disease, autoimmune enteropathy, and cytomegalovirus/infectious enterocolitis.

Comparison of Xpert Flu rapid nucleic acid testing with rapid antigen testing for the diagnosis of influenza A and B.

Influenza infections are associated with thousands of hospital admissions and deaths each year. Rapid detection of influenza is important for prompt initiation of antiviral therapy and appropriate patient triage. In this study the Cepheid Xpert Flu assay was compared with two rapid antigen tests, BinaxNOW Influenza A & B and BD Directigen EZ Flu A+B, as well as direct fluorescent antibody testing for the rapid detection of influenza A and B. Using real-time, hydrolysis probe-based, reverse transcriptase PCR as the reference method, influenza A sensitivity was 97.3% for Xpert Flu, 95.9% for direct fluorescent antibody testing, 62.2% for BinaxNOW, and 71.6% for BD Directigen. Influenza B sensitivity was 100% for Xpert Flu and direct fluorescent antibody testing, 54.5% for BinaxNOW, and 48.5% for BD Directigen. Specificity for influenza A was 100% for Xpert Flu, BinaxNOW, and BD Directigen, and 99.2% for direct fluorescent antibody testing. All methods demonstrated 100% specificity for influenza B. These findings support the use of the Xpert Flu assay in settings requiring urgent diagnosis of influenza A and B.

Immunohistochemical panel for distinguishing esophageal adenocarcinoma from squamous cell carcinoma: a combination of p63, cytokeratin 5/6, MUC5AC, and anterior gradient homolog 2 allows optimal subtyping.

Distinguishing adenocarcinoma and squamous cell carcinoma of the esophagus is often based on morphological criteria and can be difficult in small biopsies. We analyzed commonly used immunohistochemical markers (p63, cytokeratin 5/6, cytokeratin 7, CDX2, MUC2, and MUC5AC) and 2 new markers, anterior gradient homolog 2 and SOX2, in esophageal carcinomas to establish the best panel to distinguish these tumors. Tissue microarrays with 69 esophageal adenocarcinomas and 41 whole sections of esophageal squamous cell carcinomas were stained for these markers and semiquantitatively scored. Sensitivities and specificities were calculated for individual markers and select combinations using the morphological diagnosis as a gold standard. All squamous cell carcinomas expressed p63 with 38 of 41 demonstrating reactivity in more than 75% of tumor cells. Cytokeratin 5/6 expression was seen in 40 of 41 squamous cell carcinomas with 39 of 41 demonstrating reactivity in more than 75% of tumor cells. SOX2 expression was present in 35 of 41 of squamous cell carcinomas but also in 24 of 69 of adenocarcinomas, frequently demonstrating extensive reactivity in adenocarcinomas. Anterior gradient homolog 2 was highly sensitive for adenocarcinoma and present in 68 of 69 of cases, but anterior gradient homolog 2 reactivity was also identified in 15 of 41 of squamous cell carcinomas, typically demonstrating focal reactivity in squamous cell carcinoma. MUC5AC expression was seen almost exclusively in adenocarcinomas with only a single squamous cell carcinoma demonstrating focal MUC5AC staining. Overall, the dual expression of both p63 and cytokeratin 5/6 was 99% specific and 98% sensitive for squamous cell carcinoma. In addition, anterior gradient homolog 2 and MUC5AC are useful positive markers of adenocarcinoma in the setting of absent or diminished p63 and cytokeratin 5/6 staining.

Intraductal Papillary Mucinous Neoplasms Often Contain Epithelium From Multiple Subtypes and/or Are Unclassifiable.

Pancreatic intraductal papillary mucinous neoplasms (IPMNs) are subclassified into gastric, intestinal, pancreatobiliary, and oncocytic subtypes based on histologic features. The WHO classification scheme suggests use of immunohistochemical stains to help subtype IPMNs with ambiguous histology. Seventy-two pancreatic IPMN resections between 2008 and 2014 were retrospectively evaluated. Immunohistochemistry for CDX2, MUC2, and MUC5AC was performed on cases where the histologic subtype could not be determined on routine hematoxylin and eosin (H&E) sections. There were 41 gastric (57%), 8 intestinal (11%), 4 pancreatobiliary (6%), and 1 oncocytic (1%) IPMNs. Eighteen (25%) IPMNs were either unclassifiable due ambiguous morphology or contained distinct epithelium from >1 subtype (ie, “mixed”). Two IPMNs initially unclassifiable strictly by H&E morphology were definitively classified as intestinal after positive immunohistochemical staining with CDX2, MUC2, and MUC5AC. Immunohistochemistry for another 7 IPMNs unclassifiable by H&E did not indicate a clear subtype and often contained discordant results (eg, discordant CDX2 and MUC2 staining). In our experience, a considerable number of IPMNs are either unclassifiable or contain epithelium from >1 subtype. Furthermore, among those IPMNs initially unclassifiable by H&E morphology, application of immunohistochemical stains to aid in subtyping allow for definite classification in only a small subset of cases. These data, when taken in context with the significant ranges in the reported prevalence of specific histologic subtypes, suggest that accurate IPMN subtyping is poorly reproducible in up to 25% of cases, and in these problematic cases, immunohistochemistry adds little value.

Lymphoid Hyperplasia of the Appendix: A Potential Pitfall in the Sonographic Diagnosis of Appendicitis

OBJECTIVE The objective of this study was to test the hypothesis that thickening of the lamina propria, a finding produced by lymphoid hyperplasia, is significantly associated with false-positive sonographic diagnoses of appendicitis in 6- to 8-mm noncompressible appendixes. MATERIALS AND METHODS Sonograms of 119 consecutive patients with suspected appendicitis and 6- to 8-mm noncompressible appendixes were retrospectively blindly evaluated for thickening of the lamina propria (short axis thickness ≥ 1 mm). The reference standard for appendicitis was pathologic analysis of resected specimens. Results were compared with the two-tailed Fisher exact test. RESULTS Thirty-one patients (26.1%) had a thickened lamina propria and 88 (73.9%) did not. Of the 27 pediatric patients with a thickened lamina propria, five (18.5%) had true-positive and 22 (81.5%) had false-positive sonograms for appendicitis; among the 55 pediatric patients without a thickened lamina propria, 27 (49.1%) had true-positive and 28 (50.9%) had false-positive sonograms for appendicitis (p = 0.009). Similar differences in adult patients were not statistically significant. All five pediatric patients with appendicitis and thickened lamina propria also showed two or more findings of periappendiceal fluid, hyperechoic periappendiceal fat, or mural hyperemia on color Doppler examination, compared with two of 22 similar pediatric patients without appendicitis (p < 0.001). CONCLUSION Lymphoid hyperplasia may result in a noncompressible appendix 6-8 mm in diameter and may be misdiagnosed as appendicitis in pediatric patients. True-positive diagnoses of appendicitis can be accurately identified by the presence of at least two additional findings from the group of periappendiceal fluid, hyperechoic periappendiceal fat, and mural hyperemia. Identifying the characteristic sonographic appearance of lymphoid hyperplasia may help prevent false-positive misdiagnoses of appendicitis.

Color Doppler Imaging of the Appendix Criteria to Improve Specificity for Appendicitis in the Borderline-Size Appendix

To test the hypothesis that continuous intramural vascular signal measuring at least 3 mm on color Doppler imaging is highly specific for appendicitis in patients with diagnostically borderline‐size appendices.

MDCT Diagnosis of Perineural Invasion Involving the Celiac Plexus in Intrahepatic Cholangiocarcinoma: Preliminary Observations and Clinical Implications

OBJECTIVE The purpose of this study was to test the hypothesis that soft-tissue infiltration along the celiac plexus and delayed enhancement exceeding two-thirds of the tumor area on preoperative MDCT correlate with histologic evidence of perineural invasion in resected intrahepatic cholangiocarcinomas. MATERIALS AND METHODS Two experienced abdominal radiologists retrospectively reviewed preoperative multiphasic MDCT scans of 20 patients who underwent resection of intrahepatic cholangiocarcinoma, identifying soft-tissue infiltration along the celiac plexus, delayed enhancement exceeding two-thirds of the tumor area, and maximum tumor diameter. Consensus findings were compared with intratumoral perineural invasion in resected intrahepatic cholangiocarcinomas using the Fisher exact test. RESULTS Six patients had histologic intratumoral perineural invasion, five of whom had soft-tissue infiltration along the celiac plexus on preoperative MDCT, with corresponding 83.3% sensitivity and 92.9% specificity for perineural invasion and significant association between these MDCT and histologic findings (p = 0.002). No patients with histologic perineural invasion had enhancement exceeding two-thirds of the tumor area on MDCT; sensitivity was 0.0% for this finding. Tumor diameter on MDCT was not significantly associated with perineural invasion at histopathology (p = 0.530). CONCLUSION Soft-tissue infiltration along the celiac plexus on MDCT is an indicator of perineural invasion in patients with intrahepatic cholangiocarcinoma. The data did not confirm an association between delayed enhancement exceeding two-thirds of the tumor area and perineural invasion. Because perineural invasion from intrahepatic cholangiocarcinoma is associated with a very poor prognosis and is generally a contraindication to surgery, the MDCT diagnosis of celiac plexus perineural invasion in patients with intrahepatic cholangiocarcinoma may have important implications for prognosis and treatment planning.

The Sonographic “Bright Band Sign” of Splenic Infarction

To evaluate the frequency of the “bright band sign” in patients with splenic infarcts as well as control patients and to thereby assess whether the bright band sign has potential utility as a sonographic sign of splenic infarction.

Colloid Carcinoma of the Pancreas

A 70-year-old male presented with a several-month history of steatorrhea and a 50-pound weight loss. He denied abdominal, flank, or back pain. His past medical history was notable for type 2 diabetes mellitus, hyperlipidemia, and coronary artery disease. His past surgical history was unremarkable. He denied any alcohol use and had no history of pancreatitis. Work-up prior to presentation included a negative colonoscopy, and a computed tomography (CT) scan of the abdomen showed a diffusely enlarged pancreas with a markedly dilated main pancreatic duct. The gland was essentially replaced by calcifications and the splenic vein was occluded. No discrete solid pancreatic mass was seen (Fig. 1). There was no ultrasonographic evidence of gallstones. These findings were initially interpreted as chronic pancreatitis, and the patient was treated for pancreatic insufficiency with oral pancreatic enzyme supplementation. On presentation, physical examination revealed a wellappearing although very slender man. His abdominal exam was notable for fullness in the epigastrium and right upper quadrant. Laboratory studies were notable for mild hyperbilirubinemia of 2.3 mg/dL, markedly elevated alkaline phosphatase of 1145 U/L, and mildly elevated aminotransferase levels with aspartate aminotransferase (AST) of 144 U/L and alanine aminotransferase (ALT) of 140 U/L. Of his serum tumor markers, carcinoembryonic antigen (CEA) was significantly elevated at 102.7 ng/mL, whereas his carbohydrate antigen (CA) 19-9 was normal at less than 1 U/mL. Interpretation of endoscopic ultrasonography (EUS) was limited because of the presence of massive calcifications. At endoscopic retrograde cholangiopancreatography (ERCP), mucus was noted to extrude from the ampulla of Vater. After contrast injection, filling defects that changed in shape, consistent with mucus, were evident within the dilated pancreatic and bile ducts (Fig. 2). After sphincterotomy, balloon sweeps were performed, extracting contrast and mucus. At pancreatoscopy, the visualized pancreatic ductal epithelium appeared bland with no obvious papillary projections. However, a transampullary biopsy of the pancreatic ductal epithelium revealed bland mucinous epithelium consistent with intraductal papillary mucinous neoplasm (IPMN). Instead of chronic pancreatitis, an IPMN involving the main pancreatic duct was diagnosed and the patient underwent a total pancreatectomy (Fig. 3). Macroscopically, the entire gland was noted to have gross tumor involvement. The patient had an uneventful postoperative course and was discharged home 8 days later on insulin and exocrine pancreatic enzyme supplementation. Pathology showed marked calcifications, foci of necrotic yellow gelatinous material, and cystic areas throughout the entire pancreatic parenchyma with no apparent normal lobular pancreatic parenchyma (Fig. 4). The lining epithelium of the cysts ranged from bland mucinous epithelium to areas of invasive carcinoma with a prominent desmoplastic stromal response, and mucin dissecting through the stroma and small bowel muscularis. Many mucin pools were noted T. A. Plerhoples M. Ahdoot G. A. Poultsides (&) Department of Surgery, Stanford University Medical Center, Stanford, CA, USA e-mail: gpoultsides@stanford.edu