How useful is PET/CT imaging in the management of post-transplant lymphoproliferative disease after liver transplantation?

Rare Case of Pediatric Post-transplant Lymphoproliferative Disorder Presenting With Pleural Masses Complicated by Pleural Effusions

Post-transplant lymphoproliferative disorder is a complication in organ transplant recipients characterized by uncontrolled proliferation of B-lymphocytes, occurring in 6% of pediatric patients, with risk factors including primary Epstein-Barr virus infection, intensity of immunosuppression, and cytomegalovirus infection. The clinical symptoms are often nonspecific, and it is associated with a high mortality rate if left untreated. We describe a rare case of post-transplant lymphoproliferative disorder who presented with pleural-based masses resulting in pleural effusions.

Clinical Utility of 18Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) in Multivisceral Transplant Patients

Multivisceral transplant (MVTx) refers to a composite graft from a cadaveric donor, which often includes the liver, the pancreaticoduodenal complex, and small intestine transplanted en bloc. It remains rare and is performed in specialist centres. Post-transplant complications are reported at a higher rate in multivisceral transplants because of the high levels of immunosuppression used to prevent rejection of the highly immunogenic intestine. In this study, we analyzed the clinical utility of 28 ¹⁸F-FDG PET/CT scans in 20 multivisceral transplant recipients in whom previous non-functional imaging was deemed clinically inconclusive. The results were compared with histopathological and clinical follow-up data. In our study, the accuracy of ¹⁸F-FDG PET/CT was determined as 66.7%, where a final diagnosis was confirmed clinically or via pathology. Of the 28 scans, 24 scans (85.7%) directly affected patient management, of which 9 were related to starting of new treatments and 6 resulted in an ongoing treatment or planned surgery being stopped. This study demonstrates that ¹⁸F-FDG PET/CT is a promising technique in identifying life-threatening pathologies in this complex group of patients. It would appear that ¹⁸F-FDG PET/CT has a good level of accuracy, including for those MVTx patients suffering from infection, post-transplant lymphoproliferative disease, and malignancy.

Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

PTLD with the response-dependent sequential use of RIS, rituximab, and cytotoxic chemotherapy is recommended. Evidence gaps requiring future research and alternate treatment strategies including immunotherapy are highlighted.

Inflammatory and Ischemic Post Liver Transplant Complications Mimic Malignancy on 18F-FDG PET/CT

A 65-year-old male patient with a one year history of liver transplantation was referred for an ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to rule out post transplant lymphoproliferative disease. Multiple foci of intense abnormal ¹⁸F-FDG uptake were seen in the transplanted liver which were concerning for malignancy. Explantation of the liver approximately 1 month following the PET/CT revealed multiple inflammatory and ischemic changes including large bile duct necrosis, acute cholangitis, bile duct obstruction changes and periportal fibrosis, with no evidence of malignancy. We present the ¹⁸F-FDG PET/CT image findings of this case.

Preliminary experience on the use of PET/CT in the management of pediatric post-transplant lymphoproliferative disorder

INTRODUCTION

Post-transplant lymphoproliferative disorder (PTLD) is a well-known complication following prolonged immunosuppression. Contrary to other lymphomas, there is no standardized imaging approach to assess PTLD either at staging or for response to therapy. Positron emission tomography/computed tomography (PET/CT) is an imaging modality that has proven to be useful in lymphoma. However, there is still limited data concerning its use in pediatric PTLD. Our study evaluates the use of PET/CT in pediatric PTLD at our institution.

METHODS

To assess the role of PET/CT in pediatric PTLD, we reviewed the pediatric patients with PTLD who had undergone PET/CT at our institution between 2000 and 2016.

RESULTS

Nine patients were identified. Six had PET/CT at diagnosis. All lesions seen on CT were identified with PET/CT. Fourteen PET/CTs were done during treatment. Eight PET/CTs were negative, including three where CT showed areas of uncertain significance. In these cases, PET/CT helped us to stop treatment and the patients remain in remission after a long follow-up (mean 74.3 months; range 12.4-180.9 months). PET/CT revealed additional disease in two cases, therefore treatment was intensified. Six biopsies and close follow-up was done to confirm PET/CT results. In one case, PET/CT did not identify central nervous system involvement demonstrated on magnetic resonance imaging.

CONCLUSION

PET/CT may have an important role in the staging and follow-up of pediatric PTLD. In our cohort, PET/CT was helpful in staging and assessing treatment response and in clarifying equivocal findings on other imaging modalities.

Posttransplant Lymphoproliferative Disorder: Otolaryngological Manifestations and Management

Objective

Posttransplant lymphoproliferative disorder (PTLD) is a unifying term for a spectrum of lymphoid expansion entities brought about by immunosuppression and is strongly associated with Epstein-Barr virus (EBV). Otolaryngological findings tend to present early in the clinical course; therefore, disease awareness among otolaryngologists is of utmost importance. This review synthesizes the body of literature pertaining to PTLD involving the head and neck, summarizes contemporary management, and highlights areas for future research.

Data Sources

PubMed/Medline.

Review Methods

Primary literature search of the Medline database was performed for all titles published in the past 10 years pertaining to PTLD. The database search included PTLD combined with a collection of otolaryngological MeSH terms. Full manuscripts were reviewed based on relevance of their title and abstract. Selection into this review was according to clinical and scientific relevance.

Conclusion

Adenotonsillar focus is common in children in whom adenotonsillectomy may be diagnostic and prevents potentially morbid airway obstruction. Sinonasal PTLD may mimic fungal infection. Laryngotracheal involvement predominately presents in children with symptoms of airway obstruction. PTLD limited to the esophagus is rare. Oral PTLD is rare and phenotypically varied. Cutaneous presentation of PTLD is infrequent, yet one-third of cases affects the head and neck. PTLD may present as cervical lymphadenopathy.

Implications for Practice

PTLD consideration is vital when evaluating posttransplant patients. Children and EBV-seronegative patients should receive otolaryngological follow-up after transplant. PTLD treatment is multidisciplinary and typically led by lymphoma specialists. Formal partnerships between otolaryngologists and transplant centers may improve patient care and research quality.

18F-FDG PET/CT for the Diagnosis of Malignant and Infectious Complications After Solid Organ Transplantation

PURPOSE

Infection and malignancy represent two common complications after solid organ transplantation, which are often characterized by poorly specific clinical symptomatology. Herein, we have evaluated the role of ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) in this clinical setting.

METHODS

Fifty-eight consecutive patients who underwent FDG PET/CT after kidney, lung or heart transplantation were included in this retrospective analysis. Twelve patients underwent FDG PET/CT to strengthen or confirm a diagnostic suspicion of malignancies. The remaining 46 patients presented with unexplained inflammatory syndrome, fever of unknown origin (FUO), CMV or EBV seroconversion during post-transplant follow-up without conclusive conventional imaging. FDG PET/CT results were compared to histology or to the finding obtained during a clinical/imaging follow-up period of at least 6 months after PET/CT study.

RESULTS

Positive FDG PET/CT results were obtained in 18 (31 %) patients. In the remaining 40 (69 %) cases, FDG PET/CT was negative, showing exclusively a physiological radiotracer distribution. On the basis of a patient-based analysis, FDG PET/CT's sensitivity, specificity, PPV and NPV were respectively 78 %, 90 %, 78 % and 90 %, with a global accuracy of 86 %. FDG PET/CT was true positive in 14 patients with bacterial pneumonias (n = 4), pulmonary fungal infection (n = 1), histoplasmosis (n = 1), cutaneous abscess (n = 1), inflammatory disorder (sacroiliitis) (n = 1), lymphoma (n = 3) and NSCLC (n = 3). On the other hand, FDG PET/CT failed to detect lung bronchoalveolar adenocarcinoma, septicemia, endocarditis and graft-versus-host disease (GVHD), respectively, in four patients. FDG PET/CT contributed to adjusting the patient therapeutic strategy in 40 % of cases.

CONCLUSIONS

FDG PET/CT emerges as a valuable technique to manage complications in the post-transplantation period. FDG PET/CT should be considered in patients with severe unexplained inflammatory syndrome or FUO and inconclusive conventional imaging or to discriminate active from silent lesions previously detected by conventional imaging particularly when malignancy is suspected.

Epstein-Barr Virus-Positive Posttransplant Lymphoproliferative Disease After Solid Organ Transplantation: Pathogenesis, Clinical Manifestations, Diagnosis, and Management

Posttransplant lymphoproliferative disease (PTLD) is a potentially fatal complication after (solid organ) transplantation, which is highly associated with Epstein-Barr virus (EBV). The EBV-specific cytotoxic T cell response that is essential in controlling the virus in healthy individuals is suppressed in transplant recipients using immunosuppressive drugs. A primary EBV infection in EBV-seronegative patients receiving an EBV-seropositive donor organ or a reactivation in those who are already latently infected pretransplantation can lead to uninhibited growth of EBV-infected B cells and subsequently to PTLD. Effective preventive strategies, such as vaccines and antiviral agents, are lacking. Because not every transplant recipient with increasing EBV viral load develops PTLD, it is hard to decide how intensively these patients should be monitored and how and when a preemptive intervention should take place. There is a need for other tools to help predict the development of PTLD in patients at risk to make timing and strategy of preemptive intervention easier and more reliable.

The cornerstone of the treatment of patients with PTLD is restoring the host's immunity by reduction of immunosuppressive drug therapy. American and British guidelines recommend to add rituximab monotherapy or rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisolone, depending on histology and clinical characteristics. Although response to these therapies is good, toxicity is a problem, and PTLD still has a relatively high mortality rate. An evolving therapy, especially in PTLD occurring in allogeneic stem cell transplantation, is restoring the host's immune response with infusion of EBV-specific cytotoxic T cells. This may also play a role in the future in both prevention and treatment of PTLD in SOT.

Hilar cholangiocarcinoma: expert consensus statement

An American Hepato-Pancreato-Biliary Association (AHPBA)-sponsored consensus meeting of expert panellists met on 15 January 2014 to review current evidence on the management of hilar cholangiocarcinoma in order to establish practice guidelines and to agree consensus statements. It was established that the treatment of patients with hilar cholangiocarcinoma requires a coordinated, multidisciplinary approach to optimize the chances for both durable survival and effective palliation. An adequate diagnostic and staging work-up includes high-quality cross-sectional imaging; however, pathologic confirmation is not required prior to resection or initiation of a liver transplant trimodal treatment protocol. The ideal treatment for suitable patients with resectable hilar malignancy is resection of the intra- and extrahepatic bile ducts, as well as resection of the involved ipsilateral liver. Preoperative biliary drainage is best achieved with percutaneous transhepatic approaches and may be indicated for patients with cholangitis, malnutrition or hepatic insufficiency. Portal vein embolization is a safe and effective strategy for increasing the future liver remnant (FLR) and is particularly useful for patients with an FLR of <30%. Selected patients with unresectable hilar cholangiocarcinoma should be evaluated for a standard trimodal protocol incorporating external beam and endoluminal radiation therapy, systemic chemotherapy and liver transplantation. Post-resection chemoradiation should be offered to patients who show high-risk features on surgical pathology. Chemoradiation is also recommended for patients with locally advanced, unresectable hilar cancers. For patients with locally recurrent or metastatic hilar cholangiocarcinoma, first-line chemotherapy with gemcitabine and cisplatin is recommended based on multiple Phase II trials and a large randomized controlled trial including a heterogeneous population of patients with biliary cancers.

Nuclear imaging for functional evaluation and theragnosis in liver malignancy and transplantation

Currently, nuclear imaging such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) is increasingly used in the management of liver malignancy. ¹⁸F-fluorodeoxyglucose (FDG)-PET is the most widely used nuclear imaging in liver malignancy as in other cancers, and has been reported to be effective in diagnosis, response monitoring, recurrence evaluation, and prognosis prediction. Other PET imaging such as ¹¹C-acetate PET is also used complementarily to FDG-PET in diagnosis of liver malignancy. Additionally, image-based evaluation of regional hepatic function can be performed using nuclear imaging. Those imaging modalities are also effective for candidate selection, treatment planning, and perioperative evaluation in liver surgery and transplantation. Recently, nuclear imaging has been actively adopted in the transarterial radioembolization therapy of liver malignancy, according to the concept of theragnosis. With the development of new hybrid imaging technologies such as PET/magnetic resonance imaging and SPECT/CT, nuclear imaging is expected to be more useful in the management of liver malignancy, particularly regarding liver surgery and transplantation. In this review, the efficacy and roles of nuclear imaging methods in diagnosis, transplantation and theragnosis are discussed.

Still's Disease in a Pediatric Patient after Liver Transplantation

Still's disease (SD) is a multisystemic inflammatory disease characterized by persistent arthritis and in many cases with fever of unknown origin. Diagnosis of SD is challenging because of nonspecific characteristics and especially in the case of a patient with solid organ transplantation and immunosuppressive therapy where multiple causes of fever are possible. There is no diagnostic test for SD, even though some useful diagnostic criteria or laboratory findings, such as serum ferritin levels, have been proposed, and useful imaging studies for the diagnosis or followup of SD have not been developed. We report the case of a 9-year-old child who presented with high grade fever associated with joint pain after a history of liver transplantation and immunosuppressive therapy. Laboratory tests showed increased acute phase reactants, elevated ferritin, and leukocytosis. An 18 F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) was performed identifying abnormal hypermetabolic areas localized in spleen, transplanted liver, and bone marrow secondary to inflammatory process. All infectious, autoimmune, and malignant causes were ruled out. A diagnosis of SD was performed and a steroid-based regimen was initiated with adequate response and no evidence of recurrence. To our knowledge this is the first case of SD following a solid organ transplant.

(18)F-fluorodeoxyglucose positron emission tomography/computed tomography in diagnosis of post-transplant lymphoproliferative disorder

The aim of the present study was to investigate the role of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in the diagnosis of post-transplant lymphoproliferative disorder (PTLD), a serious complication of solid organ and bone marrow transplant. Between January 2004 and January 2012, 40 patients (22 males; median age 52 ± 17.4 years, range 11-77 years) underwent (18)F-FDG PET/CT scans in our department for diagnostic evaluation of PTLD. Twenty-three (57.5%) patients had negative (18)F-FDG PET/CT and 17 (42.5%) had a positive examination. In five patients PET/CT revealed extranodal disease (adrenal, pleural, spleen, liver, lung, esophagus and bone involvement). On the basis of our results, (18)F-FDG PET/CT had a sensitivity of 88.2% (95% confidence interval [CI] 0.62-0.98), a specificity of 91.3% (CI 0.70-0.98), a positive predictive value of 88.2% (CI 0.62-0.98) and a negative predictive value of 91.3% (CI 0.70-0.98). The diagnostic performance of CT in patient-based analysis was: a sensitivity of 87.5% (CI 0.60-0.97), a specificity of 88.8% (CI 0.64-0.98), a positive predictive value of 87.5% (CI 0.60-0.97) and a negative predictive value of 88.8% (CI 0.64-0.98). PET/CT in five cases revealed more findings than CT, upstaging the disease, and revealed three extranodal findings, not visualized in conventional imaging. (18)F-FDG PET/CT plays a significant role in the setting of PTLD diagnosis, demonstrating its high accuracy in detecting PTLD.

Uncommon gastrointestinal complications after liver transplantation: radiologic findings and clinical features

There are various uncommon gastrointestinal complications, as liver transplantation becomes increasingly popular as the only curative method for patients with end-stage liver diseases. It is important for radiologists evaluating postoperative liver transplantation recipients to have a perspective on the possible gastrointestinal complications after liver transplantation and their radiologic features for early detection and early treatment. This article illustrates radiologic findings and clinical features of various uncommon gastrointestinal complications after liver transplantation.

Chest neoplasms with infectious etiologies

A wide spectrum of thoracic tumors have known or suspected viral etiologies. Oncogenic viruses can be classified by the type of genomic material they contain. Neoplastic conditions found to have viral etiologies include post-transplant lymphoproliferative disease, lymphoid granulomatosis, Kaposi’s sarcoma, Castleman’s disease, recurrent respiratory papillomatosis, lung cancer, malignant mesothelioma, leukemia and lymphomas. Viruses involved in these conditions include Epstein-Barr virus, human herpes virus 8, human papillomavirus, Simian virus 40, human immunodeficiency virus, and Human T-lymphotropic virus. Imaging findings, epidemiology and mechanism of transmission for these diseases are reviewed in detail to gain a more thorough appreciation of disease pathophysiology for the chest radiologist.

Epstein-Barr Virus-related post-transplant lymphoproliferative disorders: pathogenetic insights for targeted therapy

Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of major, life-threatening lymphoproliferative diseases occurring in the post-transplant setting. The majority of PTLD is of B-cell origin and is associated with several risk factors, the most significant being Epstein-Barr virus (EBV) infection. EBV's in vitro transforming abilities, distinctive latency, clonality within the malignant cells and response to targeted therapies implicate a critical role in the biology of PTLD. This minireview focuses on EBV-related PTLD pathogenesis, in particular the interplay between aspects of the EBV life cycle and latency with nonviral factors resulting in the wide spectrum of histology and clinical presentations encountered in PTLD. With the increased prevalence of transplantation a rise in the incidence of PTLD may be expected. Therefore the importance of laboratory and animal models in the understanding of PTLD and the development of novel therapeutic approaches is discussed.

Positron emission tomography scanning in the setting of post-transplant lymphoproliferative disorders

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of transplantation. We examined the role of positron emission tomography (PET) scanning in PTLD.

METHODS

All patients treated for PTLD from 2001-2006 who also underwent PET scans were reviewed.

RESULTS

Nineteen PTLD patients were included. Seventeen patients had PET scans for staging at diagnosis. Of these, two patients with primary central nervous system lymphoma and one patient with only bone marrow involvement after complete surgical resection of a bowel lesion had no abnormalities on CT or PET scan. The remaining patients had measurable, extracranial disease by CT scan and PET scan. The median maximum standard uptake value was 8.2 (range 3-30). Thirteen patients had a PET scan following treatment. Eleven of 13 patients had a complete response (CR). Two of 13 patients had persistent disease following therapy; in one of these patients, relapsed disease was documented by PET scan alone. Of the 11 patients with CR, three patients relapsed shortly thereafter. In each case, at the time of relapse, the PET scan confirmed recurrent disease regardless of histopathologic subtype.

CONCLUSIONS

PET scans may have a role in the staging and follow-up of patients with PTLD. Additional prospective studies are warranted.

Diagnosis of post-transplant lymphoproliferative disorder in solid organ transplant recipients - BCSH and BTS Guidelines

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Transplantation Society (BTS) has reviewed the available literature and made recommendations for the diagnosis and management of post-transplant lymphoproliferative disorder (PTLD) in adult recipients of solid organ transplants. This review details the risk factors predisposing to development, initial features and diagnosis. It is important that the risk of developing PTLD is considered when using post transplant immunosuppression and that the appropriate investigations are carried out when there are suspicions of the diagnosis. These must include tissue for histology and computed tomography scan to assess the extent of disease. These recommendations have been made primarily for adult patients, there have been some comments made with regard to paediatric practice.

Imaging of the transplant liver

As the number of patients with liver transplants continues to increase, radiologists need to be aware of the normal post-operative appearance of the different liver transplants currently performed along with the wide variety of complications encountered. The complications commonly affect the biliar and vascular systems and can include anastomotic bile leakage and biliary stenosis along with stenosis or obstruction of the hepatic artery, portal or hepatic veins and IVC. Other complications include parenchymal abnormalities such as hepatic infarction, organ rejection, localized collections and post transplant lymphoproliferative disorder. This article reviews and illustrates the role of imaging for pediatric transplantation including the role of interventional radiology.

Posttransplant lymphoproliferative diseases

The risk of developing cancer after solid organ transplantation (SOT) is about 5- to 10-fold greater than that of the general population. The cumulative risk of cancer rises to more than 50% at 20 years after transplant and increases with age, and so children receiving transplants are at high risk of developing a malignancy. Posttransplant lymphoproliferative disease (PTLD) is the most common cancer observed in children following SOT, accounting for half of all such malignancies. PTLD is a heterogeneous group of disorders with a wide spectrum of pathologic and clinical manifestations and is a major contributor to long-term morbidity and mortality in this population. Among children, most cases are associated with Epstein-Barr virus infection. This article reviews the pathology, immunobiology, epidemiology, and clinical aspects of PTLD, underscoring the need for ongoing systematic study of complex biologic and therapeutic questions.

Imaging of posttransplantation lymphoproliferative disorder after solid organ transplantation

Posttransplantation lymphoproliferative disorders (PTLDs) are a heterogeneous group of diseases that represent uncommon complications of transplantation and can lead to significant morbidity and mortality. PTLD is most prevalent during the first year following transplantation and occurs most frequently in multiorgan transplant recipients, followed by bowel, heart-lung, and lung recipients. It may involve any of the organ systems, with disease manifestation and the anatomic pattern of organ involvement being highly dependent on the type of transplantation. The current classification system includes four subtypes that have different prognoses requiring different treatment strategies. Tissue sampling is necessary for diagnosis and further subcategorization. The majority of cases are characterized by B-cell proliferation and are related to infection from Epstein-Barr virus. Knowledge of the distribution and radiologic features of PTLD allows the radiologist to play a pivotal role in making an early diagnosis and in guiding biopsy.

Lung cancer and lung transplantation: a review

With the increase in the number of lung transplants, it is expected that there will be a corresponding increase in the number of lung cancers reported in these patients. Longevity of the transplant recipients, lung transplantation for chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis, a history of smoking, and the increasing age of the lung donors make lung cancer more likely. Nodules and masses seen in chest imaging in lung transplant patients call for work up until a final diagnosis is achieved because there is a high likelihood of a serious infection or malignancy. The presence of a native lung is a major risk factor for lung cancer occurring in the transplant setting. Lung cancer of donor origin is rare. Bronchioloalveolar carcinoma confined to one lung can potentially be treated by transplanting the affected lung. Treatment for patients with lung cancer in the lung transplant setting has to be individualized because of the complexity of their medical problems and multiple medications. Attention needs to be focused on detecting lung cancer early in these patients to achieve a favorable outcome.

Post-transplant lymphoproliferative disease

Post-transplant lymphoproliferative disease (PTLD) emerged in the mid-1990s as a major graft- and life-threatening complication of pediatric kidney transplantation. This condition, usually involving uncontrolled B lymphocyte proliferation, straddles the border between infection and malignancy, since Epstein-Barr virus (EBV) is intimately associated with the pathogenesis. PTLD is seen more in younger children (more likely to be EBV seronegative), Caucasian race, and in association with the more potent immunosuppression drugs. The clinical presentation typically involves multiple enlarged lymph nodes but varies based on localization of the lymphadenopathy. The diagnosis is based primarily on histopathological features. Treatment strategies include reduction of immunosuppression, use of anti-B cell antibodies, infusion of EBV-specific cytotoxic T lymphocytes, and chemotherapy. Many different strategies have been tried to prevent PTLD, ranging from serial EBV viral load monitoring and pre-emptive immunosuppression reduction to anti-viral prophylaxis. None of the major treatment or prevention strategies has been subject to randomized clinical trials, so their relative efficacy is still unknown. PTLD remains a risk factor for graft loss, though re-transplants have not, to date, been associated with repeat PTLD.

Successful prolonged rituximab treatment for post-transplant lymphoproliferative disorder following living donor liver transplantation in a child

PTLD is a serious complication of immunosuppression in solid organ transplant recipients. The incidence of PTLD is significantly higher in pediatric recipients than in adult because children are often EBV-seronegative and they may develop primary EBV infection after transplantation. We herein describe a case of GI-PTLD who achieved a complete remission by prolonged rituximab, a chimeric monoclonal antibody against CD20, mono-therapy. A one-yr-old female underwent a LDLT for liver failure after having previously undergone the Kasai procedure for biliary atresia. At sixty days following the transplantation, GI-PTLD developed. Withdrawal of immunosuppression and a surgical resection were thus performed. A histopathological examination of tumor revealed atypical medium to large cell lymphoid proliferation with strong CD20 immunopositivity indicating their B-cell origin. Polymorphic PTLD was diagnosed. Rituximab was administered at a dose of 375 mg/m2 once a week, and the monotherapy resulted in a complete remission after 34 administrations. Based on this case, rituximab appears to be beneficial as a first-line therapy for PTLD.

Post transplant lymphoproliferative disease in pediatric solid organ transplant patients: a possible role for [18F]-FDG-PET(/CT) in initial staging and therapy monitoring

Post transplant lymphoproliferative disease (PTLD) is a severe complication after solid organ or bone marrow transplantation. In pediatric transplant recipients PTLD is the most common malignancy. The aim of this study was to evaluate a possible role for positron emission tomography with [18F]-2-fluoro-2-desoxy-glucose (FDG) in the initial staging and in therapy monitoring of pediatric patients suffering from biopsy-proven CD20-positive PTLD after solid organ transplantation. Seven pediatric patients were included. All available imaging studies - CT (n=15), MRI (n=16) and PET/PETCT (n=16) - were reviewed on a lesion by lesion base. The performance of FDG-PET in the initial staging and during therapy with a chimeric anti-CD20 antibody was compared to conventional cross sectional imaging and correlated with the clinical outcome. FDG-PET identified all sites of disease as shown by CT/MRI and helped to clarify the significance of equivocal findings. The initial stage of disease was correctly identified by FDG-PET alone when compared to CT/MRI. During therapy, FDG-PET was superior to conventional cross-sectional imaging in the early evaluation of response.