Answer for BIR CoW 21 Sep 2025
Swyer Syndrome / XY Gonadal Dysgenesis
Relevant Clinical Findings
Discussion
46, XY pure gonadal dysgenesis (Swyer syndrome) is a rare form of primary amenorrhea caused by gonadal dysgenesis. Despite a 46, XY karyotype, patients exhibit a female phenotype.
The pathogenesis is most often related to mutations or deletions in the SRY gene located on the short arm of the Y chromosome.
Key diagnostic considerations:
Investigations recommended:
Differential diagnoses:
References
Relevant Clinical Findings
- Uterus: Hypoplastic, measuring 27 × 24 × 9 mm, with thin endometrial line and corpus–cervix ratio of 1:1.
- Right gonad: Identified, measuring 9 × 4 mm.
- Left gonad: Not visualized.
- Other findings: Left ectopic pelvic kidney.
- Karyotyping: 46, XY.
- Diagnostic laparoscopy with gonadectomy: Both gonads identified.
- Histopathology (HPE): Seminiferous tubules lined by Sertoli cells without spermatogonia – features of testicular tissue with epididymis and cord structures.
Discussion
46, XY pure gonadal dysgenesis (Swyer syndrome) is a rare form of primary amenorrhea caused by gonadal dysgenesis. Despite a 46, XY karyotype, patients exhibit a female phenotype.
The pathogenesis is most often related to mutations or deletions in the SRY gene located on the short arm of the Y chromosome.
Key diagnostic considerations:
- Suspect Swyer syndrome in primary amenorrhea with presence of a uterus.
- Confirm with chromosomal analysis.
- Gonads are typically absent or streak-like; uterus and fallopian tubes may be absent or underdeveloped.
Investigations recommended:
- Serum electrolytes
- LH, FSH
- Prolactin
- TSH, Free T4
- SHBG, androstenedione, estradiol, testosterone
- Tumor markers: α-fetoprotein, β-hCG, LDH, PLAP
- Optional: AMH and inhibin, though limited additional value if FSH is elevated
Differential diagnoses:
- Complete Androgen Insensitivity Syndrome (CAIS):
- Female phenotype with normal breast development
- Morphologically normal (often undescended) testes
- Absent Müllerian structures (including uterus)
- Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome:
- Variable Müllerian duct/vaginal aplasia with rudimentary uterus
- Normal female genotype and secondary sexual characteristics
References
- Singh S, Ilyayeva S. Androgen Insensitivity Syndrome.
- Hughes IA, Davies JD, Bunch T, Pasterski V, Mastroyannopoulou K, MacDougal J. Androgen Insensitivity Syndrome.
- Pathak S, Raj G, Pratap R, Singh S. Late Presentation of Swyer Syndrome: A Case Report.
- King TFJ, Conway GS. Swyer Syndrome.
- Boruah DK, Sanyal S. Spectrum of MRI Appearance of Mayer–Rokitansky–Küster–Hauser (MRKH) Syndrome in Primary Amenorrhea Patients.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!