Familial Male-limited Precocious Puberty (FMPP) and Testicular Germ Cell Tumors

Objective: The purpose of this study is to report development of a malignant testicular germ cell tumor (GCT) in 2 young adult males with familial male-limited precocious puberty (FMPP) because of LHCGR pathogenic variants in 2 families. Secondarily, to study the possible relation between FMPP and testicular tumors and to investigate whether FMPP might predispose to development of malignant testicular tumors in adulthood a literature review is conducted. Methods: Data on 6 cases in 2 families are obtained from the available medical records. In addition, a database search is performed in Cochrane, PubMed, and Embase for studies that report on a possible link between FMPP and testicular tumors. Results: The characteristics of 6 males with FMPP based on activating LH receptor (LHCGR) germline pathogenic variants are described, as are details of the testicular GCTs. Furthermore, a literature review identified 4 more patients with signs of FMPP and a (precursor of) testicular GCT in adolescence or adulthood (age 15-35 years). Additionally, 12 patients with signs of precocious puberty and, simultaneously, occurrence of a Leydig cell adenoma or Leydig cell hyperplasia are reported. Conclusion: There is a strong suggestion that FMPP might increase the risk of development of testicular GCTs in early adulthood compared with the risk in the general population. Therefore, prolonged patient monitoring from mid-pubertal age onward including instruction for selfexamination and periodic testicular ultrasound investigation in patients with a germline LHCGR pathogenic variant might contribute to early detection and thus early treatment of testicular GCT. Key Words: testotoxicosis, familial male limited precocious puberty, activating luteinizing hormone receptor, testicular tumors, germ cell tumors, peripheral precocious puberty Abbreviations: FMPP, familial male-limited precocious puberty; GCT, germ cell tumor; LHCGR, LH/choriogonadotropin receptor; LCT, Leydig cell tumor; MAS, McCune Albright syndrome; SRY, Sex-determining Region Y.