Introduction: Usual sex determination and differentiation occurs progressively during the period of embryonic development, involving chromosomal differentiation, gonadal differentiation, and somatic or genital differentiation. Swyer syndrome is a disorder of sex chromosomes and sexual differentiation characterized by 46, XY pure gonadal dysgenesis in a phenotypically female person with primary amenorrhea, and a complete absence of functioning gonadal tissue. Gonadal malignancy occurs in 10-30% of cases, so gonadectomy is indicated at the time of diagnosis. The treatment includes, in addition to the gonadectomy, hormone replacement therapy, and psychological support. Objective: To present a case diagnosed and managed in our institution, in addition to reviewing the recent literature about this rare condition, but with a strong physical, psychological and social impact. Methods: Analysis of clinical history of a patient with Swyer's Syndrome, diagnostic and therapeutic management. Bibliographic review. Presentation of the clinical case: An 18-year-old patient attends our hospital presenting primary amenorrhea. She presents BMI: 22; Tanner stage PH III BD III, gynecological examination with vulva and vagina with normal characteristics. Hormone profile requested: FSH 96.8 mU/ml, LH 32.9 mU/ml, Estradiol <25 pg/ml; Total testosterone 0.15 ng/ml. TV ultrasound shows a hypoplastic uterus of 23x11x29 mm, ovaries are not visualized, and a heterogeneous solid image of 22x23x24 mm in the left adnexal region. 46XY karyotype. In the presence of these results, a diagnosis of Swyer's syndrome is made, so an MRI was requested, which shows a uterus of 14x20x26 mm, ovaries are not visualized, a solid lobulated oval image of 23x33x47 mm poorly vascularized standing out in the left adnexal region and free inguinal canals. It was decided to perform exploratory laparoscopy and gonadectomy. The intraoperative findings were: intrapelvic hypoplastic uterus, uterine tubes without any particularities, enlarged left gonad of approximately 3x4 cm pearly white with a hard elastic consistency, and a fibrous band in the right adnexa. Bilateral adnexectomy was performed, obtaining as a histological result well-differentiated left dysgerminoma SALL4 +, OCT3/4 +, negative Inhibin and CD 117 +, and right streak gonad. Conclusions: In the presence of a person with primary amenorrhea and absence or poor development of secondary sex characteristics, Swyer's syndrome should be suspected, and pertinent studies should be requested to arrive at the diagnosis. It is essential to perform gonadectomy at the time of diagnosis due to the risk of malignant transformation. The importance of a multidisciplinary approach and psychological accompaniment of patients and relatives is highlighted.