From the Guidelines
Histochemical stains such as OCT4, CD30, and SALL4 can be used to distinguish between seminoma, embryonal carcinoma, and other germ cell tumors, while inhibin, calretinin, and FOXL2 are useful for identifying granulosa cell tumors. The most recent and highest quality study 1 provides a comprehensive overview of the immunohistochemical markers used in the diagnosis of germ cell tumors and sex cord-stromal tumors.
Key Findings
- Seminoma can be identified by positive staining for OCT4 and SALL4, while embryonal carcinoma shows positive staining for CD30, OCT4, and SALL4.
- Choriocarcinoma can be identified by positive staining for human chorionic gonadotropin (hCG) and cytokeratins.
- Granulosa cell tumors demonstrate positive staining for inhibin, calretinin, and FOXL2, while being negative for PLAP and CD30.
Diagnostic Approach
- A combination of histological examination and immunohistochemical staining is essential for accurate diagnosis.
- The use of a panel of immunohistochemical markers, including OCT4, CD30, SALL4, inhibin, calretinin, and FOXL2, can help distinguish between different types of germ cell tumors and sex cord-stromal tumors.
- Expert pathological evaluation is crucial for accurate diagnosis and treatment planning, as recommended by 1.
Clinical Implications
- Accurate diagnosis of germ cell tumors and sex cord-stromal tumors is critical for determining prognosis and guiding treatment.
- The use of immunohistochemical stains can help identify specific tumor types and inform treatment decisions, as discussed in 1 and 1.
- A multidisciplinary approach, including expert pathological evaluation and clinical correlation, is essential for optimal patient care.
From the Research
Histochemical Stains for Testicular Tumors
To distinguish between seminoma, embryonal carcinoma, choriocarcinoma, and granulosa cell tumor, several histochemical stains can be used:
- OCT4: Expressed in seminoma and embryonal carcinoma, making it a useful marker for these tumors 2
- D2-40: Positive in seminoma, but also shows focal positivity in some embryonal carcinomas, limiting its utility in distinguishing between these two tumors 3
- CD30: Expressed in embryonal carcinoma, but can also be found focally in seminoma, particularly in mixed tumors 4, 5
- CD117 (c-kit): Regularly expressed in seminoma, but not in embryonal carcinoma, making it a useful marker in combination with CD30 for distinguishing between these two tumors 5
- Cytokeratin 7 (CK7), inhibin, and p63: Useful markers for choriocarcinoma, with CK7 being highly sensitive and inhibin and p63 being sensitive and specific for choriocarcinoma versus seminoma, embryonal carcinoma, and yolk sac tumor 6
- β-human chorionic gonadotropin (β-hCG): Can be used to identify choriocarcinoma, but is not as specific as CK7, inhibin, and p63, as it can also be expressed in other tumor types 6
Specific Stains for Each Tumor Type
- Seminoma: OCT4, D2-40, CD117 (c-kit)
- Embryonal carcinoma: OCT4, CD30
- Choriocarcinoma: CK7, inhibin, p63, β-hCG
- Granulosa cell tumor: No specific stains mentioned in the provided studies, but inhibin can be used to identify sex-cord stromal tumors, which include granulosa cell tumors 2