Primary Central Nervous System Posttransplant Lymphoproliferative Disease in a Bilateral Transfemoral Lower Extremity Transplantation Recipient

A World Update of Progress in Lower Extremity Transplantation: What's Hot and What's Not

ABSTRACT

The field of vascularized composite allotransplantation (VCA) is the new frontier of solid organ transplantation (SOT). VCA spans life-enhancing/life-changing procedures such as upper extremity, craniofacial (including eye), laryngeal, tracheal, abdominal wall, penis, and lower extremity transplants. VCAs such as uterus transplants are life giving unlike any other SOT. Of all VCAs that have shown successful intermediate- to long-term graft survival with functional and immunologic outcomes, lower extremity VCAs have remained largely underexplored. Lower extremity transplantation (LET) can offer patients with improved function compared to the use of conventional prostheses, reducing concerns of phantom limb pain and stump complications, and offer an option for eligible amputees that either fail prosthetic rehabilitation or do not adapt to prosthetics. Nevertheless, these benefits must be carefully weighed against the risks of VCA, which are not trivial, including the adverse effects of lifelong immunosuppression, extremely challenging perioperative care, and delayed nerve regeneration. There have been 5 lower extremity transplants to date, ranging from unilateral or bilateral to quadrimembral, progressively increasing in risk that resulted in fatalities in 3 of the 5 cases, emphasizing the inherent risks. The advantages of LET over prosthetics must be carefully weighed, demanding rigorous candidate selection for optimal outcomes.

Primary central nervous system post-transplantation lymphoproliferative disorder: A case report and systematic review of imaging findings

Primary central nervous system post-transplant lymphoproliferative disease (PCNS-PTLD) is a rare subset of post-transplant lymphoproliferative disorder (PTLD) isolated to the CNS without nodal or extra-nodal organ involvement [1,2]. PCNS-PTLD occurs primarily in patients following either solid organ transplants or hematopoietic stem cell transplants and tends to be monomorphic DLBCL. The development of PCNS-PTLD is commonly associated with EBV infection [3]. Many intracranial pathologies can resemble the imaging appearance of PCNS-PTLD, including primary CNS lymphoma, glial tumors, metastatic disease, and intracranial abscesses. The purpose of this systematic review is to identify the most common imaging characteristics of PCNS-PTLD. Our review included 97 sources that describe the imaging appearance of PCNS-PTLD. Based on our review, PCNS-PTLD lesions are typically multifocal, ring-enhancing and diffusion-restricting. PCNS-PTLD lesions typically demonstrate focal FDG avidity. Despite advancement in medical imaging, PCNS-PTLD remains a diagnostic challenge due to its rare incidence. Limited data is available on advanced imaging with regards to PTLD, but techniques including DCE-MRI and fMRI demonstrate promising results that may help further delineate PCNS-PTLD.

Case Report: Post-transplant lymphoproliferative disorder as a serious complication of vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) is an emerging field in transplant surgery. Despite overall positive outcomes, VCA confers risk for multiple complications related to the procedure and subsequent immunosuppression. Post-transplant lymphoproliferative disorder (PTLD) is a heterogeneous group of lymphoproliferative disorders occurring after solid organ and hematopoietic stem cell transplant. A patient with PTLD after bilateral upper extremity transplantation is presented as well as a review of all known cases of PTLD after VCA, with a focus on the unique epidemiology, presentation, and treatment in this population.

Addressing common orthopaedic calamities with microsurgical solutions

Reconstructive microsurgery has been an essential aspect of orthopaedic surgery and extremity reconstruction since the introduction of the operating microscope in the mid-20^th century. The reconstructive ladder ranges from simple healing by secondary intention to complex procedures such as free tissue transfer and vascularized composite allotransplantation. As orthopaedic surgery has evolved over the past 60 years, so too have the reconstructive microsurgical skills that are often needed to address common orthopaedic surgery problems. In this article, we will discuss a variety of complex orthopaedic surgery scenarios ranging from trauma to infection to tumor resection as well as the spectrum of microsurgical solutions that can aid in their management.

Unique Techniques or Approaches in Microvascular and Microlymphatic Surgery

Several methods can be used for identifying tissues for transfer in donor-site-depleted patients. A fillet flap can be temporarily stored in other parts of the body and transferred back to the site of tissue defect, including covering the amputated stump of the lower extremity. Human arm transplant is rare and has some unique concerns for the surgery and postsurgical treatment. Cosmetics of the narrow neck of transferred second toes can be improved with insertion of a flap. Lymphedema of the breast after cancer treatment can be diagnosed with several currently available imaging techniques and treated surgically with lymphaticovenous anastomosis.

Innovations in reconstructive microsurgery: Reconstructive transplantation

In the past 20 years, reconstructive transplantation (RT) has emerged as a viable reconstructive option for carefully selected patients. More than 100 upper extremity and 40 face transplants have been performed worldwide to date. Concomitantly, the portfolio of reconstructive transplantation has been extended by additional procedures such as lower extremities, abdominal wall, neck, uterus, genitourinary, and pediatric transplants. In the present review article, we aim to summarize the current state of knowledge about this exciting field.

Primary Central Nervous System Hodgkin Lymphoma-Like Posttransplant Lymphoproliferative Disorder

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD) is a rare condition occurring after organ transplantation. PTLD comprises 4 subtypes, of which Hodgkin lymphoma (HL) type and HL-like type (currently included in polymorphic type) account for only about 1%-3% of cases. Primary central nervous system PTLD is also rare; most cases are Epstein-Barr virus-positive, B-cell PTLD. To our knowledge, no case of HL-like PTLD has been documented.

CASE DESCRIPTION

A 43-year-old woman who underwent kidney transplantation for IgA nephropathy 14 years previously presented to the emergency department with seizure. Gadolinium-enhanced T1-weighted magnetic resonance imaging showed a ring-enhancing mass in the left temporal lobe. Gross total removal of the tumor was performed, and pathologic examination revealed findings consistent with HL-like PTLD. The patient's immunosuppressants were subsequently reduced, and she received postoperative systemic therapy with rituximab and radiation therapy. Follow-up magnetic resonance imaging showed no signs of relapse.

CONCLUSIONS

This represents an extremely rare case of a patient with HL-like PTLD occurring as a primary central nervous system lesion.

Vascularized Composite Allotransplantation: Medical Complications

The objective of this review is to summarize the collective knowledge regarding the risks and complications in vascularized composite tissue allotransplantation (VCA), focusing on upper extremity and facial transplantation. The field of VCA has entered its second decade with an increasing experience in both the impressive good outcomes, as well as defining challenges, risks, and experienced poor results. The limited and selective publishing of negative outcomes in this relatively new field makes it difficult to conclusively evaluate outcomes of graft and patient survival and morbidities. Therefore, published data, conference proceedings, and communications were summarized in an attempt to provide a current outline of complications. These data on the medical complications of VCA should allow for precautions to avoid poor outcomes, data to better provide informed consent to potential recipients, and result in improvements in graft and patient outcomes as VCA finds a place as a therapeutic option for selected patients.

Role of microRNAs in primary central nervous system lymphomas

Primary central nervous system lymphomas (PCNSL) are extranodal non-Hodgkin lymphomas arising exclusively inside the CNS, and account for about 3% of primary intracranial tumours. This tumour lacks systemic manifestations and prognosis of patients with PCNSL remains poor despite recent advancement of chemoradiotherapy. MicroRNAs are small non-coding RNAs that post-transcriptionally downregulate gene expression by binding to target mRNAs, inducing their degradation or translational repression. MicroRNAs play significant roles in almost all malignancy-related biological processes, including cell proliferation, differentiation, apoptosis and metabolism. Many deregulated miRNAs has been identified in PCNSL but their biological significance remains to be fully elucidated. In this review, we summarize current evidence regarding the pathogenic role of PCNSL-associated microRNAs and their potential applications for diagnosis and prognostication of this deadly disease.