Primary Amenorrhea in an 18-Year-Old Phenotypic Female With a 46,XY Karyotype: Complete Androgen Insensitivity Syndrome.

Complete androgen insensitivity syndrome (CAIS) is an uncommon disorder of sexual differentiation in which a genetically male (46,XY) individual presents with a typical female phenotype due to androgen receptor resistance. We report the case of an 18-year-old phenotypic female with primary amenorrhea and lower abdominal pain. Clinical assessment showed normal breast development with markedly reduced body and pubic hair. Hormonal studies revealed elevated LH and testosterone levels. Imaging confirmed the absence of Müllerian structures, and karyotyping demonstrated a 46,XY pattern. Bilateral laparoscopic orchidectomy was carried out, followed by estrogen therapy and psychological support. This case highlights the clinical clues essential for the early diagnosis of CAIS and underscores the need for empathetic counselling and coordinated multidisciplinary care.