A Case of Cutaneous T Cell Lymphoma After Kidney Transplant

Introduction: Post-transplant lymphoproliferative disorders (PTLDs) represent a rare but known complication of solid organ transplant. World Health Organization (WHO) classifies PTLD into four categories: early lesions, polymorphic PTLD, monomorphic PTLD, and classical Hodgkin's lymphoma. PTLD originating from T cell lymphomas is uncommon and primary cutaneous lymphomas comprise the least frequent subgroup. Here we present a case of Cutaneous T-cell lymphoma (CTCL) arising post kidney transplant. Case Description: A 28-year-old African American male with end stage kidney disease secondary to reflux nephropathy underwent a deceased donor kidney transplant in October 2021. He had immediate graft function and serum creatinine stabilized around 1.4-1.7 mg/dl. The Immunosuppression regimen consisted of Tacrolimus dosed to target trough level of 5-8 ng/mL and Mycophenolic acid 180 mg twice daily. Three years post-transplant, he developed an asymptomatic rash on his back. On examination, he had scattered follicular accentuated erythematous patches throughout his back. Scalp, face, arms, legs, chest and abdomen were spared. Over-the-counter steroids provided minimal relief. Punch biopsy showed atypical perifollicular and perieccrine T-cell infiltrate, suspicious for mycosis fungoides follicular tropic variant with predominant CD3 positive T cells. JAK 2 mutation testing and peripheral blood flow cytometry were negative with no evidence of systemic lymphoma. Mycophenolic acid was stopped and Tacrolimus trough target level was reduced to 4-5 ng/mL. Additionally, he was treated with 2-3 weekly sessions of whole body UVB radiation. He had significant improvement in dermatologic symptoms. Discussion: PTLD is an unfortunate complication of solid organ transplant. Most PTLDs arise from B cells and are associated with EBV. In contrast, PTLD from T cells are rare with anaplastic large cell lymphoma being the most common variant among these subgroups. In contrast to B cell lymphomas, T cell lymphomas are reported to have less favorable prognosis necessitating a high index of suspicion. Per literature review, fewer than 100 cases have been reported and CTCL develops on average 6-7 years post-transplant. In our patient, CTCL developed 3 years post-transplant and was limited to skin. In addition, the disease has followed an indolent course and responded to reduction in immunosuppression and whole body UVB radiation.