Abstract
INTRODUCTION: This study investigated the clinical characteristics, diagnostic considerations, and optimal management of a neonatal mature teratoma arising from an intra-abdominal cryptorchid testis complicated by torsion, a rare clinical entity. METHODS: We retrospectively analyzed data from a full-term male neonate admitted in November 2025 with a prenatally detected intra-abdominal mass, including postnatal imaging, tumor marker assessment, surgical excision, and pathological confirmation. Concurrently, we conducted a systematic review of English-language literature using PubMed, Embase, Cochrane Library, and Web of Science. RESULTS: The patient was diagnosed with a mature teratoma originating from an intra-abdominal cryptorchid testis. Intraoperative findings revealed 360° clockwise torsion causing colonic compression. Complete resection resulted in an uneventful recovery, with a physiological decline in serum alpha-fetoprotein (AFP) levels consistent with postnatal age-related maturation, and no recurrence at one-month follow-up. The literature review identified ten cases (including the present case) of prenatally detected ultrasound-detected tumors with progressive tumor growth. Surgical management primarily involved laparoscopic surgery (40.0%) or laparotomy (60.0%). Mature teratomas were the predominant pathology (90.0%), tumor torsion occurred in 20.0% of cases, and no recurrences were reported, indicating a favorable prognosis. CONCLUSION: Neonatal mature teratomas arising from an intra-abdominal cryptorchid testis with torsion are exceedingly rare. Evaluation of testicular position should be routine in male neonates with intra-abdominal masses, and gonadal tumors should be included in the differential diagnosis. Multidisciplinary, individualized management is essential for optimizing outcomes.