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Abstract: SA-PO510

A Case of Hypercalcemia Exacerbated by Ectopic 1,25(OH)2D Expressed in Post-Transplant Lymphoproliferative Disorder (PTLD) 13 Years After Kidney Transplantation

Session Information

Category: Fluid‚ Electrolyte‚ and Acid-Base Disorders

  • 1002 Fluid‚ Electrolyte‚ and Acid-Base Disorders: Clinical

Authors

  • Kozuka, Kazumi, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Nakagawa, Yosuke, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Isozumi, Konomi, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Koizumi, Masahiro, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Komaba, Hirotaka, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Wada, Takehiko, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
  • Fukagawa, Masafumi, Tokai Daigaku Igakubu Jin Naibunpi Taisha Naika, Isehara, Kanagawa, Japan
Introduction

Post-transplant lymphoproliferative disorder (PTLD) develops in 1-3% of kidney transplant recipients. Paraneoplastic hypercalcemia is frequently seen in patients with malignant lymphoma, but is rarely seen in patients with PTLD. Here, we report a case of PTLD presenting with progressive hypercalcemia associated with ectopic calcitriol synthesis at 13 years following deceased donor kidney transplantation.

Case Description

A 59-year-old man was admitted to our hospital with a 6-week history of generalized weakness, appetite loss, and extremities edema. He had been on hemodialysis for 23 years and had received a deceased donor kidney transplant 13 years before presentation. He showed no evidence of rejection with immunosuppressants, and his serum creatinine persisted 1.5 to 1.6 mg/dL thereafter. He also had secondary hyperparathyroidism which was well controlled by oral calcimimetics. On examination, he showed severe pitting edema of extremities particularly in the left leg and swollen left knee joint. His serum calcium increased from 10.6 to 15.6 mg/dL for 6 weeks, with suppressed parathyroid hormone (PTH) level (58 pg/mL) and undetectable PTH-related peptide level. Further investigations revealed an increased 1,25(OH) 2 D level of 122 pg/mL (normal range 20-60). Analysis of the knee joint fluid showed atypical lymphocyte infiltration, and flow cytometry revealed a monoclonal lambda-restricted B-cell population, suggesting B cell lymphoma. He was treated with intravenous normal saline and subsequently with a dose of denosumab, but he developed severe acidemia with worsening kidney function and became hemodynamically unstable.
Continuous hemodialysis was started on hospital day 2. He underwent R-CHOP treatment, but the lymphoma did not respond to the treatment, and he died on hospital day 6. Autopsy showed massive lymphoma infiltration in iliopsoas muscle, residual kidneys, large and small intestine, and the patient was finally diagnosed as diffuse large B-cell lymphoma. An increased level of 1,25(OH)2D suggested ectopic calcitriol synthesis in the lymphoma.

Discussion

PTLD should be considered as a differential diagnosis of unexplained hypercalcemia in kidney transplant recipients.