Microscopic features associated with mycophenolate mofetil in gastric and colonic biopsies

Drug-induced digestive tract injury: decoding some invisible offenders

There is an ever-growing list of pharmacological agents, several of which are attributed to cause clinically significant gastrointestinal (GI) injury. Many patients present with significant but nonspecific symptoms, that in conjunction with the absence of relevant drug history on the requisition slip can make the histopathologic diagnosis challenging. To complicate this, although some drugs have relatively characteristic histopathologic features (such as doxycycline), there exist many other drugs that exhibit wide and varying spectra of histopathologic findings (such as immune checkpoint inhibitors or olmesartan) and have histomorphologic overlap with many other commonly encountered disease entities. This review discusses the histopathologic features of some relatively recently described drugs causing GI tract injury, namely doxycycline, tacrolimus, mycophenolate, immune checkpoint inhibitors, and olmesartan. We also discuss the common mimics in histopathologic differential and some pearls that can help distinguish GI tract injury induced by the aforementioned drugs from its mimics. Awareness of the wide spectra of histopathologic changes associated with these drugs is crucial for practicing pathologists, to avoid misdiagnosis and guiding the clinician for an optimal patient management, which usually involves modifying or discontinuing the offending drug. Needless to say, once a diagnosis of drug-induced injury is suspected, clinicopathologic correlation including corroboration with the drug history is of utmost importance as is the exclusion of dual pathology in these patients.

Characterization of Mycophenolate Mofetil Gastrointestinal Toxicity and Risk Factors for Severe Disease and Poor Prognosis

Authors performed a chart review to identify cases of mycophenolate mofetil gastrointestinal toxicity at our institution. In this cohort, friability was associated with severe disease; and nausea and erythema were associated with poor prognosis.

Histologic Features of Tacrolimus-induced Colonic Injury

Tacrolimus is a common immunosuppressant used in solid organ transplant recipients. Although most patients develop diarrheal symptoms, data regarding patterns of injury in patients taking tacrolimus are limited. We performed this study to characterize tacrolimus-related features of colonic injury. We retrospectively identified colonic samples from 20 patients receiving tacrolimus monotherapy. Records were reviewed for symptoms, endoscopic findings, other medications, and infections. None of the patients had gastrointestinal infections or used other drugs known to cause colonic injury; none had received mycophenolate within 6 months of presentation. Cases were evaluated for the nature and distribution of inflammation and crypt abnormalities, including distortion, destruction, and apoptosis. Eighteen (90%) patients were solid organ transplant recipients. Seventeen (85%) had gastrointestinal symptoms, particularly diarrhea (75%). More than 50% had endoscopic colitis and 15% had ulcers and/or erosions. Most (90%) cases showed regenerative epithelial changes; apoptotic crypt cells were present in 55% and numerous in 10% of cases. Neutrophilic cryptitis was present in 60% of cases; 35% showed crypt destruction. Plasma cell-rich lamina propria inflammation and crypt distortion were observed in 40% and 25% of cases, respectively. There was no correlation between therapy duration and features of chronic injury. We conclude that tacrolimus can cause symptomatic colitis. Histologic abnormalities are often mild, featuring regenerative crypts and scattered apoptotic debris. However, 40% of symptomatic patients have chronic colitis, most likely reflecting drug-induced immune dysregulation. Pathologists should be aware of these associations because colitis often resolves with decreasing drug dosage rather than treatment directed toward inflammatory bowel disease.

Cecum perforation induced by mycophenolate mofetil after hematopoietic stem cell transplantation: A case report and review of literature

GI perforation after stem cell transplantation is extremely rare and is associated with poor prognosis. In addition, the clinical limitations of MMF are associated with GI intolerance and hematologic suppression. However, the exact mechanism whereby MMF induces changes in GI mucosa is unknown. Currently, there is no definite method to distinguish between GI toxicity associated with MMF and GVHD. It is important to recognize association between MMF and the histologic changes mimicking GVHD, given that GVHD is a significant differential diagnosis in stem cell transplant patients. MMF-induced colitis and GI perforation are extremely rare but should be considered in patients presenting with diarrhea and abdominal pain. Histology and clinical features are helpful to distinguish this condition from ischemic colitis. Early recognition of GI perforation is necessary for proper diagnosis and subsequent intervention. Emergency medical treatment and laparotomy have been shown to reduce the risk of fatal complications in patients presenting with GI symptoms suspected of GI perforation.

Differentiating Posttransplant Inflammatory Bowel Disease and Other Colitides in Renal Transplant Patients

Renal transplant recipients who present with gastrointestinal complaints may have symptoms related to their underlying renal disease or secondary to their immunosuppressive regimen. Immunosuppression increases patients' risk for infection and medication-induced injury, and a subset of transplant patients develop a form of inflammatory bowel disease (IBD) despite being immunosuppressed. In this study, we present the spectrum of changes in colonic biopsy histology that occur in the postrenal transplant population, with emphasis on the clinical and histologic features that may allow distinction between several common disorders. Over a 15-year period, 51 postrenal transplant patients underwent colonoscopy with biopsy. Eleven (22%) patients had infectious colitis, and 10 of these had biopsy proven acute colitis. Another 17 (33%) patients were determined to have a medication-related injury based on resolution of symptoms following drug cessation. The majority (53%) of these colonic biopsies demonstrated crypt epithelial cell apoptosis and/or architectural distortion, although 41% were histologically normal. Four (8%) patients were ultimately diagnosed with a form of IBD after exclusion of other etiologies; biopsies from these patients demonstrated chronic active colitis or enteritis with plasma cell-rich expansion of the lamina propria and basal lymphoplasmacytosis. The increased prevalence of IBD in this patient cohort (4/700) compared with that reported in the overall North American population (1 to 2/700) is in line with prior studies and is likely related to the therapeutic regimen and associated immune dysregulation that occurs in solid-organ transplant recipients. We demonstrate that a combination of clinical, endoscopic, and histologic features are useful to distinguish among causes of gastrointestinal symptoms in this high risk population.

The Impact of New Technologic and Molecular Advances in the Daily Practice of Gastrointestinal and Hepatobiliary Pathology

The practice of anatomic pathology, and of gastrointestinal pathology in particular, has been dramatically transformed in the past decade. In addition to the multitude of diseases, syndromes, and clinical entities encountered in daily clinical practice, the increasing integration of new technologic and molecular advances into the field of gastroenterology is occurring at a fast pace. Application of these advances has challenged pathologists to correlate newer methodologies with existing morphologic criteria, which in many instances still provide the gold standard for diagnosis. This review describes the impact of new technologic and molecular advances on the daily practice of gastrointestinal and hepatobiliary pathology. We discuss new drugs that can affect the gastrointestinal tract and liver, new endoluminal techniques, new molecular tests that are often performed reflexively, new imaging techniques for evaluating hepatocellular carcinoma, and modified approaches to the gross and histologic assessment of tissues that have been exposed to neoadjuvant therapies.

Iatrogenic pathology of the intestines

Many drugs and chemical agents can cause enteritis and colitis, producing clinical gastrointestinal side effects, the most common of which are diarrhoea, constipation, nausea and vomiting. Significant histological overlap exists between some patterns of medication or chemical injury and various disease entities. A particular medication may cause multiple patterns of injury and may mimic common entities such as coeliac disease, Crohn's disease, infectious enteritis and colitis. Thus, given the common absence of specific histopathological features, the diagnosis often relies upon thorough clinicopathological correlation. This review concentrates on selected examples of medication-induced injury of the intestinal tract in which the pathology can be recognized, particularly on biopsies, with a focus on newly described medication-induced gastrointestinal effects.

Nodular hyperplasia of the gastrointestinal tract after liver transplantation: role of immunosuppressive therapy? A case report

Nodular lymphoid hyperplasia (NLH) of the gastrointestinal tract is a rare disease usually reported in patients with congenital or acquired immunodeficiency and chronic gastrointestinal infections. However, no case of NLH in a patient receiving immunosuppressive therapy has been reported to date. We describe the case of a woman who developed chronic diarrhea related to NLH 9 years after liver transplantation. Other causes of diarrhea and NLH were excluded. Her immunosuppressive regimen consisted on mycophenolate mofetil (MMF) and tacrolimus. Reduction of MMF dose improved symptoms but led to a rising aminotransferase level. Given the risk of graft rejection, MMF at full dose was resumed and she was started on symptomatic treatment for diarrhea. The role of immunosuppressive drugs in the pathogenesis of NLH may be related to the reduction of T- and B-lymphocyte proliferation and decreasing antibody production. NLH will further develop to compensate functionally inadequate lymphoid tissue, as reported in congenital immunodeficiency states.

Coeliac-like duodenal pathology in orthotopic liver transplant patients on mycophenolic acid therapy

AIMS

Diarrhoea following orthotopic liver transplantation (OLT) is a significant clinical problem associated with mycophenolic acid (MPA). The histological injury pattern associated with MPA in the large bowel is well documented in the literature; however, that in the duodenum is less extensively documented. The aim of this study was to investigate the histological spectrum of duodenal injury specifically in symptomatic OLT patients on MPA, and to compare this with the spectrum in patients with coeliac disease and in normal controls.

METHODS AND RESULTS

We reviewed our pathology database for all duodenal biopsies from patients on the OLT list over a period of 19 years. Medical records, anti-tissue transglutaminase IgA serology and histology were reviewed. Of the 667 patients who underwent endoscopy, 127 had duodenal biopsies (152 biopsies). Of these, 87.5% were normal. Sixteen showed abnormal histology, and seven (43.8%) of these were on MPA at the time of biopsy. Significant features included coeliac-like changes (shortened villi and increased intraepithelial lymphocyte counts), and novel findings included increased endocrine cell counts, apoptotic counts and lamina propria eosinophil counts in comparison with normal duodenal biopsies.

CONCLUSIONS

Pathologists should be aware of the features of MPA-associated duodenal injury, including coeliac-like changes and increased apoptotic counts. In those with abnormal histology, discontinuation or a reduction in the dose of MPA should be discussed.

Gastrointestinal pathology in transplant patients

The assessment of gastrointestinal (GI) specimens from transplant patients is complicated by the wide range of potentially rare pathologies that may be found in this clinical setting. Acute GI graft-versus-host disease (GvHD) is characterized by epithelial cell apoptosis, although there is increasing recognition that acute and/or chronic inflammation may also be present. By contrast, thus far there are no histological features known to be specific to chronic GI GvHD. Mycophenolate mofetil colitis may mimic both GvHD and inflammatory bowel disease, whereas both cytomegalovirus (CMV) and adenovirus infections can cause gland apoptosis. Post-transplant lymphoproliferative disorder should be considered if a Crohn's-like histological picture is seen, and granulomas in biopsies from umbilical cord blood recipients should raise a suspicion of cord colitis syndrome. Finally, the GI tract may be involved directly or indirectly by the disease that originally required haematopoietic stem cell or liver transplantation.

Clinicopathologic features and outcome of mycophenolate-induced colitis in renal transplant recipients

Reports on the clinical course of mycophenolic acid (MPA)-related colitis in kidney transplant recipients are scarce. This study aimed at assessing MPA-related colitis incidence, risk factors, and progression after kidney transplantation. All kidney transplant patients taking MPA who had colonic biopsies for persistent chronic diarrhea, between 2000 and 2012, at the Kidney Transplantation Unit of Botucatu Medical School Hospital, Brazil, were included. Cytomegalovirus (CMV) immunohistochemistry was performed in all biopsy specimens. Data on presenting symptoms, medications, immunosuppressive drugs, colonoscopic findings, and follow-up were obtained. Of 580 kidney transplant patients on MPA, 34 underwent colonoscopy. Colonoscopic findings were associated with MPA usage in 16 patients. The most frequent histologic patterns were non-specific colitis (31.3%), inflammatory bowel disease (IBD)-like colitis (25%), normal/near normal (18.8%), graft-versus-host disease-like (18.8%), and ischemia-like colitis (12.5%). All patients had persistent acute diarrhea and weight loss. Six of the 16 MPA-related diarrhea patients (37.5%) showed acute dehydration requiring hospitalization. Diarrhea resolved when MPA was switched to sirolimus (50%), discontinued (18.75%), switched to azathioprine (12.5%), or reduced by 50% (18.75%). No graft loss occurred. Four patients died during the study period. Late-onset MPA was more frequent, and no correlation with MPA dose or formulation was found.