Background: An unusual case of a peripheral T-cell lymphoma of T gamma/delta hepatosplenic type (Tgamma/deltaHSL) that arose in a child 5 years after she received a heart transplant and 9 months after she developed Epstein-Barr virus (EBV) positive, B-cell lymphoid hyperplasia involving the tonsils is presented. The majority of the reported cases of Tgamma/deltaHSL have been described in young adult men without antecedent immunodeficiency; several well documented cases of Tgamma/deltaHSL in the posttransplant setting have been described previously, but none has been described in a child (or an adult) with a previously diagnosed EBV+ B-cell lymphoid hyperplasia.
Methods: Standard histologic, immunohistochemical, flow cytometric, and molecular genetic techniques were used in the evaluation of diagnostic material.
Results: The patient's Tgamma/deltaHSL involved the spleen in a predominantly cordal pattern, and infiltrated the liver in an exclusively sinusoidal distribution. Bone marrow involvement was focal and interstitial. In all locations, malignant cells were of intermediate or large size and had oval nuclei with coarse chromatin, with a scant or moderate amount of eosinophilic cytoplasm. This Tgamma/deltaHSL expressed the characteristic CD2+, CD3+, [CD4- CD8-], Tdelta1+ phenotype, and malignant cells also expressed the natural killer cell marker CD56. Cytogenetic studies demonstrated isochromosome 7q with the addition of trisomy 8 as the tumor progressed. Southern blot analysis demonstrated clonal rearrangements of the gamma, delta, and beta loci of the T-cell receptor but did not identify EBV DNA within the tumor cells.
Conclusions: This case highlights the fact that a full range of lymphoid proliferations is possible in the posttransplantation period, and that a prior diagnosis of a B-cell disorder does not preclude the development of a subsequent T-cell posttransplant lymphoproliferative disorder (PTLD), which should be formally evaluated, especially if clinical circumstances appear atypical for a PTLD of the "usual" (EBV-related, B-cell) type.