Two cases of recurrent brain tumor during GH replacement therapy

Two cases of patients with recurrent brain tumor are presented. Each of them received growth hormone (GH) replacement therapy for growth failure secondary to cranial irradiation. The first case is that of a 10-year-old girl who was treated with a combination of surgical resection, radiotherapy and chemotherapy for cerebellar medulloblastoma at 1 y.o. At the age of 9, 10 month after the beginning of GH replacement therapy, she complained of headache. This was due to shunt malfunction when CSF cytology was class V. It revealed that there was recurrence of medulloblastoma. The second case is that of a 14-year-old girl who was treated with a combination of surgical resection, radiotherapy and chemotherapy for suprasellar germinoma at the age of 10. This tumor completely disappeared after these procedures. For her growth failure, we started GH replacement therapy and after 1 year, she complained of lt. leg pain due to tibial and pelvic bone metastasis. In medical literature, we found 15 recurrent brain tumors during GH replacement therapy. These include our 2 cases, and 9 cases in which there was recurrence within 1 year. Recently, receptors for some somatomedins have been found in brain tumors. Although these numbers are too small for us to arrive at conclusions, we think it is possible that there are some mechanisms connecting GH replacement therapy and recurrence of certain brain tumors.