Differential Diagnosis

Given the scenario where only free testosterone is slightly elevated and prolactin is low, the following differential diagnoses can be considered:

• Single most likely diagnosis
  • Polycystic Ovary Syndrome (PCOS): This condition is characterized by hyperandrogenism, which could explain the elevated free testosterone levels. Low prolactin levels do not typically contradict a diagnosis of PCOS, as prolactin levels can vary widely among individuals with this condition.
• Other Likely diagnoses
  • Congenital Adrenal Hyperplasia (CAH): Although less common, CAH can lead to elevated androgen levels, including testosterone. The low prolactin level does not specifically point towards or away from CAH, making it a consideration in the differential diagnosis.
  • Androgen-Secreting Tumors: Tumors of the adrenal gland or ovaries can produce androgens, leading to elevated testosterone levels. The absence of significantly elevated prolactin levels does not rule out this possibility.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cushing's Syndrome: Although typically associated with a broader range of hormonal imbalances, Cushing's Syndrome can lead to elevated androgen levels. It's crucial to consider this diagnosis due to its potential severity and the importance of early intervention.
  • Adrenal Carcinoma: A rare but potentially life-threatening condition that can cause an overproduction of androgens, including testosterone. The low prolactin level does not specifically indicate or rule out adrenal carcinoma.
• Rare diagnoses
  • Idiopathic Hyperandrogenism: A condition characterized by elevated androgen levels without a clear underlying cause. It's less common than PCOS but could be considered if other diagnoses are ruled out.
  • Hyperandrogenism due to other rare genetic disorders: Certain genetic conditions can lead to hyperandrogenism. These are less common and would typically be considered after ruling out more prevalent causes.

Each of these diagnoses requires careful consideration of the patient's overall clinical presentation, including symptoms, physical examination findings, and additional laboratory tests to confirm or rule out the suspected conditions.