What blood work is recommended for patients with suspected or diagnosed sex cord tumors?

Blood Work for Sex Cord Tumors

For patients with suspected or diagnosed sex cord-stromal tumors (SCSTs), obtain serum inhibin B, hCG, AFP, LDH, CA125, full blood count, and liver/renal function tests before any surgical intervention. 1

Pre-Operative Tumor Markers

Essential Markers for All Patients

• Inhibin B is the most specific marker for sex cord-stromal tumors and should be measured in all young adult patients with suspected SCSTs 1
• hCG (human chorionic gonadotropin) should be obtained, as some SCSTs can produce this marker 1
• AFP (alpha-fetoprotein) must be measured to help distinguish SCSTs from germ cell tumors, as pure SCSTs should not elevate AFP 1
• LDH (lactate dehydrogenase) provides prognostic information and should be part of the initial workup 1
• CA125 can be elevated in some SCSTs, particularly granulosa cell tumors, and is useful for monitoring 1

Additional Laboratory Tests

• Full blood count is required as part of the standard diagnostic workup 1
• Liver and renal function tests are necessary before any chemotherapy consideration 1

Specific Considerations by Tumor Type

Granulosa Cell Tumors

• Inhibin A and inhibin B are both produced by granulosa cell tumors and are elevated preoperatively in the majority of cases 2
• Serum inhibin levels decrease progressively after successful surgical removal, making them excellent markers for monitoring recurrence 2
• Inhibin alpha immunostaining is positive in 94-97% of granulosa cell tumors 3, 4
• Inhibin is more specific than calretinin for distinguishing granulosa cell tumors from epithelial neoplasms 5

Sertoli-Leydig Cell Tumors

• Inhibin is also produced by Sertoli-Leydig cell tumors, with 88% showing immunoreactivity 3
• Both inhibin A and inhibin B are produced by these tumors and can be measured in serum 2
• Testosterone and other androgens may be elevated in patients with virilizing symptoms, though this is a clinical finding rather than a routine tumor marker 1

Surveillance Monitoring Schedule

First Two Years (High-Risk Period)

• Measure serum tumor markers every 2-4 months for both germ cell and sex cord-stromal tumors 1
• Include physical examination with pelvic examination at each visit 1
• For patients who underwent fertility-sparing surgery, perform pelvic ultrasound every 6 months 1

Years 3-5

• Continue tumor marker measurements every 6 months for sex cord-stromal tumors (these have indolent behavior with late recurrences) 1
• Physical examination every 6 months 1

Beyond 5 Years

• Continue surveillance every 6 months indefinitely for sex cord-stromal tumors, as recurrences can occur more than 20 years after diagnosis (median time to relapse is 4-6 years, with documented relapses up to 37 years) 1
• Maintain tumor marker monitoring every 6 months 1

Critical Pitfalls to Avoid

Distinguishing SCSTs from Other Tumors

• Do not rely on inhibin alone to distinguish granulosa cell tumors from other sex cord-stromal tumors (fibroma-thecomas), as 71% of fibroma-thecomas are also inhibin-positive 4
• Use an immunohistochemical panel including both inhibin-alpha (most specific) and calretinin (more sensitive but less specific) for optimal diagnostic accuracy 5
• Be aware that luteinized stromal cells in various ovarian tumors can stain positive for inhibin, potentially causing false-positive interpretations 4

Marker Interpretation

• Normal inhibin levels do not exclude SCST, particularly in early-stage disease 1
• Elevated inhibin is not completely specific for SCSTs, as some endometrioid tumors (17%) and transitional cell proliferations (11%) may show weak positivity 4
• AFP elevation rules out pure sex cord-stromal tumor and suggests either a germ cell component or mixed tumor 1

Timing Considerations

• Obtain all tumor markers before orchiectomy or oophorectomy to establish baseline values for post-operative monitoring 1
• Repeat markers post-operatively until normalization to confirm complete resection 1

Special Populations

Pediatric Patients

• In children with ovarian SCSTs, endocrine symptoms are present in approximately 55% of cases and should prompt hormonal evaluation 6
• The same tumor marker panel (inhibin, hCG, AFP, LDH) applies to pediatric patients 6
• For testicular SCSTs in children, surgery alone (inguinal orchiectomy) is typically curative, but baseline markers should still be obtained 6

Patients with Tumor Rupture or Malignant Ascites

• These patients require adjuvant chemotherapy (typically platinum-based regimens like BEP) even with complete resection 1, 6
• Tumor markers should be monitored more frequently during and after chemotherapy 1