Autologous Testicular Tissue Transplantation

The eligible patients opted as a prepubertal boy to enroll in the fertility preservation program and on the moment of cancer diagnosis or hematological disorder, their parents have agreed to cryopreserve testicular tissue for later autologous transplantation. Inclusion Criteria: * At least 18 years old * In case of female partner, age \< 43 year * Absence of spermatozoa that can be used for ICSI on 2 semen analyses * Normal standardised preliminary and preoperative bloodsampling results * Complete remission of the oncological or hematological disease * Approval of the treating oncologist or other specialist in case of non-oncological disease as reason for the testicular tissue preservation as a child * Risk for presence of malignant cells in testicular tissue is negligible (according to multidisciplinary assessment) * Presence of spermatogonial stem cells (positive MAGE staining) in one or two of the thawed fragments (If absence of spermatogonial stem cells in two of the thawed fragments, the case will be discussed multidisciplinary) * Written informed consent for the transplantation of cryopreserved testicular tissue and follow-up after the procedure and of children born eventually after this procedure Exclusion criteria: * Risk for presence of malignant cells in the testicular tissue * Contra-indication for surgery * Contra-indication for pregnancy in the female partner * BMI \> 32 * Heavy smoking (≥10 cigarettes/day) * Instable psychological condition