Case Study:

Patient: Sarah, a 38-year-old woman with a history of infertility, presented with pelvic pain and a palpable abdominal mass.

Initial Diagnosis: Transvaginal ultrasound revealed a solid ovarian mass measuring 6cm, raising suspicion of a granulosa cell tumor (GCT) due to Sarah’s infertility and typical ultrasound appearance.

Challenges:

• Histological examination of a biopsy sample showed features suggestive of both GCT and SCT, but conclusive diagnosis remained elusive.
• Immunohistochemistry for common GCT markers was inconclusive, further fueling the diagnostic uncertainty.

Turning Point:

• Serum inhibin B levels were measured as part of a differential diagnosis workup.
• The result: significantly elevated inhibin B, far exceeding the expected range for GCT or a healthy individual.

Unmasking the Masquerade:

• The high inhibin B level, despite the absence of true granulosa cell components, strongly pointed towards an SCT diagnosis.
• This finding, in conjunction with the inconclusive histology, prompted the medical team to order additional tests specific for SCTs.

Confirmation and Treatment:

• Further immunohistochemistry with antibodies for Sertoli cell markers confirmed the diagnosis of SCT.
• Sarah underwent successful surgical removal of the tumor followed by adjuvant chemotherapy due to the tumor’s aggressive features suggested by the elevated inhibin B.

Impact:

• Early and accurate diagnosis of SCT using inhibin B as a key marker allowed for prompt surgical intervention and appropriate treatment, potentially improving Sarah’s long-term prognosis compared to a delayed or misdiagnosed case.
• This case highlights the critical role of inhibin B in differentiating SCTs from their mimics, especially when conventional methods fall short.

Key Takeaways:

• Inhibin B can be a powerful tool for diagnosing SCTs, even when morphology is ambiguous.
• Early and accurate diagnosis of SCTs is crucial for optimal treatment and improved patient outcomes.
• Further research is needed to refine inhibin B assays and optimize its use in routine SCT diagnosis.