(399) A Novel AMHR2 Gene Mutation Causing Transverse Testicular Ectopia Type II: A Rare Case Report and Literature Review

Abstract Introduction Transverse Testicular Ectopia (TTE) is an uncommon congenital condition typically diagnosed in childhood, characterized by the abnormal migration of both testes to the same hemiscrotum through a single inguinal canal. It is frequently associated with other congenital anomalies, including Persistent Müllerian Duct Syndrome (PMDS) and inguinal hernia.In this report, we present a rare case of TTE in an adult patient with malignant transformation, which was diagnosed preoperatively using clinical examination and magnetic resonance imaging (MRI). Genetic analysis also revealed a novel mutation in the AMHR2 gene, associated with type 2 PMDS and TTE. This mutation represents a new finding, as it has not been previously documented in the medical literature. Objective The objective of this study is to present a rare case of Transverse Testicular Ectopia (TTE) in an adult patient with malignant transformation, diagnosed through clinical examination and magnetic resonance imaging (MRI). Additionally, we aim to report a novel mutation in the AMHR2 gene associated with type 2 Persistent Müllerian Duct Syndrome (PMDS) and TTE, detected using Sanger sequencing. This case highlights the importance of early diagnosis and raises awareness of rare congenital anomalies, particularly in environments with limited access to advanced diagnostic technologies. Methods A 34-year-old male patient presented with left scrotal pain and a firm mass. His medical history included laparoscopic left inguinal hernia repair and a failed IVF attempt in 2014. Clinical examination revealed a firm right testis (50 x 50 mm) and a small, atrophic left testis located superiorly to the right one, both within the left scrotum. Results Laboratory tests showed normal complete blood count and liver/renal function, but elevated LDH, Beta HCG, AFP, prolactin, testosterone, FSH, LH, CA19-9, and SHBG. Semen analysis revealed azoospermia. MRI identified both testes in the left scrotum, passing through a single left inguinal canal, with a right testicular mass suspected to be a seminoma. The left testis was positioned superiorly with dilated vas deferens, possibly related to Müllerian duct remnants. Karyotyping revealed a 46XY chromosomal pattern. Sanger sequencing of the AMHR2 gene detected two heterozygous mutations associated with Persistent Müllerian Duct Syndrome (PMDS) type II: c.800dup (chr12:53425860-53425861) and c.1499GA (chr12:53431250), both potentially pathogenic according to ACMG criteria. These mutations have not been reported in Clinvar. Conclusions This report presents a rare case of Transverse Testicular Ectopia (TTE) type 2 associated with a novel mutation in the AMHR2 gene, linked to Persistent Müllerian Duct Syndrome (PMDS). Preoperative diagnosis through clinical evaluation and MRI enabled accurate identification of TTE. Sanger sequencing for AMH and AMHR2 mutations proved essential in confirming the diagnosis and elucidating the genetic mechanisms of TTE and PMDS. Early diagnosis improves fertility preservation, testicular function, and reduces malignancy risk. Thus, Sanger sequencing plays a critical role in both diagnosing and managing TTE. Disclosure No