Mystery Case: CNS posttransplant lymphoproliferative disorder

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.

Successful Treatment of Central Nervous System Post-Transplant Lymphoproliferative Disease With a Reduced Dose of High-Dose Methotrexate

Post-transplant lymphoproliferative disease (PTLD) is a complication of solid organ and hematopoietic stem cell transplantation that occurs as a result of immunosuppression. PTLD isolated to the central nervous system (CNS) is a rare disease and it presents with nonspecific signs and symptoms. Optimal therapy guidelines have not yet been established for CNS PTLD. Here, we report a case of successful treatment of CNS PTLD in an adult female following two subsequent kidney transplants. Initial management was with immunosuppression reduction and a trial of rituximab. There were concerns regarding using methotrexate (MTX) given the patient's fragile transplant status. Magnetic resonance imaging of the brain following four cycles of rituximab revealed the progression of the disease. Subsequently, high-dose MTX (HD-MTX) was considered within the constraints of potential kidney toxicities given her transplant status and chronic kidney disease. Potential toxicities from other therapies, such as brain radiation, also factored into the final decision. The patient was treated with one cycle of a combination of rituximab and HD-MTX 1 g/m². The patient tolerated HD-MTX and did not have evidence of renal toxicity in laboratory studies. Following that, she was started on a reduced dose of HD-MTX at 2 g/m² every two weeks instead of the higher MTX dose range of 3.5 to 8 g/m², which was a shared decision with the patient and nephrology after weighing the risk of kidney dysfunction with the possibility of a less than optimal response with regards to her lymphoma. She was followed with a magnetic resonance imaging of the brain, which demonstrated a complete response after four cycles. Further consolidation treatments with HD-MTX 2 g/m² every four weeks were administered to complete one year of treatment. Following the completion of chemotherapy, the patient was able to achieve and maintain a complete response without affecting her kidney function. She continues to do well one year following treatment. This case highlights the significance of tailoring therapy to each individual based on their comorbidities and clinical response, as well as the possible merit in exploring the use of a reduced dose of HD-MTX in the treatment of CNS PTLD in patients at high risk for renal toxicity.

Spontaneous regression of central nervous system posttransplant lymphoproliferative disease: A case report

RATIONALE

Primary central nervous system (CNS) posttransplant lymphoproliferative disease (PTLD) is a very rare entity. Patients may respond to reduction of immunosuppression or other therapies, but the prognosis is still pessimistic.

PATIENT CONCERNS

Herein, we report a 40-year-old female with a history of renal transplantation developed brain masses 4 years ago. Although brain biopsy was performed, PTLD was underdiagnosed then. No relevant treatment was administered. However, the lesions resolved spontaneously. After 4 years, new lesion appeared in a different brain region.

DIAGNOSES

The history of renal transplantation raised the suspicion of PTLD. Reexamination of previous brain sections confirmed the diagnosis of polymorphic PTLD (P-PTLD). A second biopsy of the new lesion also demonstrated P-PTLD.

INTERVENTIONS

She was referred to hematology department to receive rituximab.

OUTCOMES

After 4 rounds of treatment, the lesion resolved satisfactorily.

LESSONS

This case demonstrates the natural history of primary CNS P-PTLD. Although self-remission and recurrence is possible, aggressive measures should be taken to this condition.