Differential Diagnosis for a 15-year-old with Secondary Sexual Characteristics, Primary Amenorrhea, Psychic Pain, and Accumulation of Fluid between the Vagina and Bladder

• Single Most Likely Diagnosis
  • Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome: This condition is characterized by the congenital absence or underdevelopment of the vagina and uterus, which could explain the primary amenorrhea and the accumulation of fluid (likely hematocolpos due to an imperforate hymen or a transverse vaginal septum). Secondary sexual characteristics are usually normal due to functioning ovaries.
• Other Likely Diagnoses
  • Androgen Insensitivity Syndrome (AIS): Although less likely given the presence of psychic pain and fluid accumulation, AIS can cause primary amenorrhea. Individuals with complete AIS have a male karyotype (46,XY) but develop female secondary sexual characteristics due to resistance to androgens.
  • Transverse Vaginal Septum or Imperforate Hymen: These conditions can cause primary amenorrhea and the accumulation of menstrual blood in the vagina (hematocolpos), leading to pain and potentially the described fluid accumulation.
• Do Not Miss Diagnoses
  • Ovarian Tumors or Cysts: Although rare, ovarian tumors can produce hormones leading to precocious puberty or irregular menstrual cycles. They are a "do not miss" diagnosis due to potential malignancy.
  • Gonadal Dysgenesis: Conditions like Turner syndrome (45,X) can cause primary amenorrhea, but the presence of normal secondary sexual characteristics makes this less likely. However, mosaic Turner syndrome or other forms of gonadal dysgenesis could be considered.
• Rare Diagnoses
  • Congenital Adrenal Hyperplasia (CAH): While CAH can cause virilization and irregular menstrual cycles, it's less likely given the normal secondary sexual characteristics and the specific symptoms described.
  • Vaginal Agenesis with Functional Uterus: A rare condition where the vagina is underdeveloped or absent, but the uterus is present and functional, potentially leading to the accumulation of menstrual blood and pain.

Each diagnosis is considered based on the combination of primary amenorrhea, presence of secondary sexual characteristics, and the specific symptom of fluid accumulation between the vagina and bladder, which suggests an obstructive cause. Psychic pain could be related to the underlying condition or secondary to the physical discomfort and emotional distress associated with the symptoms.