Anatomic pathology selected abstracts

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Pittman ME, Milsom J, Yantiss RK. Treatment effects can mimic recurrent extramammary Paget disease in perianal skin. Am J Surg Pathol. 2018;42(11):1472–1479.

Correspondence: Dr. Meredith E. Pittman at mep9071@med.cornell.edu

Utility of p53 and Smad4 immunolabeling in distinguishing COD and HG-PanIN

Invasive pancreatic ductal adenocarcinoma can infiltrate and spread along pre-existing pancreatic ducts and ductules in a process known as cancerization of ducts (COD). Histologically, COD can mimic high-grade pancreatic intraepithelial neoplasia (HG-PanIN). The authors reviewed pancreatic resections from 100 patients with invasive pancreatic ductal adenocarcinoma (PDAC) for the presence or absence of ducts with histologic features of COD. Features supporting COD included adjacent histologically similar invasive PDAC and an abrupt transition between markedly atypical intraductal epithelium and normal duct epithelium or circumferential involvement of a duct. Because the TP53 and SMAD4 genes are frequently targeted in invasive PDAC but not HG-PanIN, paired PDAC and histologically suspected COD lesions were immunolabeled with antibodies to the p53 and Smad4 proteins. Suspected COD was identified on hematoxylin-and-eosin–stained sections in 89 (89 percent) of the cases. Immunolabeling for p53 and Smad4 was performed in 68 (76 percent) of 89 cases. P53 was interpretable in 55 cases, and all of those cases showed concordant labeling between COD and invasive PDAC. There was matched aberrant p53 immunolabeling in 37 (67 percent) cases, including overexpression in 30 (55 percent) cases and lack of expression in seven (13 percent) cases. Smad4 immunolabeling was interpretable in 61 cases, and 59 (97 percent) of those cases showed concordant labeling between COD and invasive PDAC. Matched loss of Smad4 was seen in 28 (46 percent) cases. The immunolabeling of invasive PDAC and COD for p53 and Smad4 supports the high prevalence of COD observed using hematoxylin and eosin and highlights the utility of p53 and Smad4 immunolabeling in differentiating COD and HG-PanIN.

Hutchings D, Waters KM, Weiss MJ, et al. Cancerization of the pancreatic ducts: demonstration of a common and under-recognized process using immunolabeling of paired duct lesions and invasive pancreatic ductal adenocarcinoma for p53 and Smad4 expression. Am J Surg Pathol. 2018;42:1556–1561.

Correspondence: Dr. R. H. Hruban at rhruban@jhmi.edu

Colonic graft-versus-host disease in transplant patients

Histologic characterization of graft-versus-host disease in autologous stem cell transplant patients has been limited. The authors conducted a study to characterize colonic graft-versus-host disease in autologous stem cell transplant patients and compare those patients with a control group of allogeneic stem cell transplant patients to determine whether the disease can be diagnosed less than 21 days post-transplantation in autologous stem cell transplant recipients. The study was also intended to quantify colonic T-cell populations in autologous stem cell transplant patients. Colonic biopsies obtained to evaluate for graft versus host disease in allogeneic and autologous stem cell transplant patients were reviewed for the maximum number of apoptotic bodies per 10 contiguous crypts. Immunohistochemical stains for CD4, CD8, and FoxP3 were performed. Clinical information was collected through chart review. The study group consisted of 122 colonic biopsies from 84 patients. Sixteen patients underwent autologous stem cell transplant, and 68 underwent allogeneic stem cell transplant. Autologous stem cell transplant patients underwent biopsy significantly earlier than allogeneic stem cell transplant patients (median, 20 versus 87 days; P = .0002), had significantly higher apoptotic counts compared with matched-related donor patients (7.5 versus 3.9; P = .03), and had higher FoxP3-positive lamina propria lymphocyte counts compared with allogeneic stem cell transplant patients (9.2 versus 5.3; P = .03). In patients undergoing biopsy less than 21 days post-transplantation, allogeneic stem cell transplant patients had fewer CD8-positive lamina propria lymphocytes and a trend of fewer FoxP3- and CD4-positive lamina propria lymphocytes compared with autologous stem cell transplant patients. Autologous stem cell transplant patients have more prominent crypt apoptosis compared with allogeneic stem cell transplant patients and do not have numerically decreased FoxP3-positive lamina propria lymphocytes. The presence of robust T-cell populations in the early period following transplantation suggests that the 21-day cutoff for diagnosing graft versus host disease is not applicable to autologous stem cell transplant patients.

Hartley CP, Carrillo-Polanco LF, Rowan DJ, et al. Colonic graft-vs.-host disease in autologous versus allogeneic transplant patients: earlier onset, more apoptosis, and lack of regulatory T-cell attenuation. Mod Pathol. 2018;31:1619–1626.

Correspondence: Dr. C. E. Hagen at cahagen@mcw.edu