Central nervous system involvement of epstein barr virus associated lymphoproliferative disorder in a child with acute lymphoblastic leukemia: successful treatment with rituximab and interferon-alpha

Case Report: Multifocal EBV-Associated Diffuse Large B-Cell Lymphoma in a Patient With 6-MP Associated Lymphopenia With TPMT Deficiency

INTRODUCTION

EBV associated lymphoproliferative disorders (EBV LPD) are a known complication following solid organ or hematopoietic stem cell transplantation. The disturbance of the immune system leads to a lack of control of latent EBV-infected B-cells, as control by T-cells is mandatory to prevent uninhibited cell proliferation. EBV LPD in other settings is less frequent and etiology and pathogenesis are not completely understood.

CASE PRESENTATION

We present the case of an 18-year old adolescent suffering from lymphoblastic T-cell lymphoma who developed a life-threatening EBV associated B-cell lymphoma while he was under therapy with 6-MP (6- mercaptopurine). An underlying homozygous TPMT (thiopurine S-methyltransferase) deficiency with subsequent insufficient degradation of 6-MP was identified as contributory for the development of a distinct lymphopenia leading to EBV LPD. The patient was successfully treated by discontinuation of 6-MP and initiating rituximab monotherapy.

DISCUSSION

Rare cases of EBV LPD during therapy with 6-MP are reported in patients with leukemia, but no data about TPMT pharmacogenomics are available. In contrast the disease development in the presented case may be explained by the iatrogenic immunosuppression in the context of TPMT deficiency. While using 6-MP testing of genetic variations is not required for every protocol, although the use of thiopurines in patients with TPMT deficiency can cause severe immunosuppression. Our case suggests that insufficient degradation of 6-MP can have significant consequences despite dose reduction.

CONCLUSION

When using thiopurines, TPMT genetics should be initiated and strict drug monitoring and dose adjusting must be performed by a specialized center.

Iatrogenic immunodeficiency-associated lymphoproliferative disorder in a child with B-cell acute lymphoblastic leukemia

Iatrogenic immunodeficiency-associated lymphoproliferative disorders (LPDs) are a group of lymphoid proliferations or lymphomas that are well known to be associated with an immunosuppressed state. These disorders most commonly occur following hematopoietic or solid organ transplantation (called post-transplant lymphoproliferative disorders or PTLD), but cases have also been described during the treatment of autoimmune and rheumatologic disorders by immunosuppressive and immunomodulatory medications. These disorders are strongly associated with infection by the Epstein-Barr virus (EBV) as a result of impaired immune function in the immunosuppressed state. While this phenomenon has been well documented in autoimmune conditions, cases affecting pediatric patients while on anti-leukemia chemotherapy are lacking. In this report, we describe a case of a pediatric immunosuppressed patient with recurrent sinusitis found to have a nasopharyngeal mass consistent with EBV-positive B-cell lymphoproliferative disorder resembling a polymorphic PTLD during the maintenance phase of B-cell Acute Lymphoblastic Leukemia (ALL) therapy. The patient was successfully treated with rituximab without any cytotoxic chemotherapy, highlighting the importance of recognizing this clinical entity in non-transplant patients with hematologic malignancies.

Facial manifestations of Epstein-Barr virus-related lymphoproliferative disease in childhood acute lymphoblastic leukemia in remission: Two atypical presentations

Epstein-Barr virus-related lymphoproliferative disease (EBV-LPD) rarely occurs in patients with acute lymphoblastic leukemia (ALL), who have not received hematopoietic transplantation. We describe EBV-LPD manifesting as facial lesions in two children with ALL in remission. One patient was a 16-year-old male with T-cell ALL with an EBV-positive angiocentric polymorphous lip lesion presenting as right-sided facial swelling. The other patient was a 12-year-old male with B-cell ALL with an EBV-positive polymorphous lymphoplasmacytic infiltrate presenting as bilateral dacryoadenitis. Neither patient had known primary immunodeficiencies. Both cases improved with immunosuppressant de-escalation. These cases suggest that immunosuppression induced by maintenance chemotherapy is sufficient to promote EBV-LPD.