Clinicopathological study of adrenal pheochromocytoma and extra-adrenal paragangliomas with reference to GAPP and...

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Metastasis in pheochromocytoma (PH) and paraganglioma (PGL) significantly impacts survival.
• Predicting malignant potential is crucial for patient prognosis.
• Existing histological algorithms, Pheochromocytoma of Adrenal Gland Scaled Score (PASS) and Grading of Adrenal Pheochromocytoma and Paraganglioma (GAPP) score, require validation.

Purpose of the Study:

• To validate the association of GAPP and PASS scores with disease outcomes in PH and PGL.
• To assess the strength of association between individual GAPP/PASS parameters and prognosis.
• To evaluate the potential improvement of SDHB immunohistochemistry in predicting prognosis.

Main Methods:

• Prospective study of 22 pheochromocytomas and 8 paragangliomas.
• Calculation of GAPP scores for paragangliomas and both GAPP/PASS scores for pheochromocytomas.
• Correlation of GAPP/PASS risk stratification with disease outcomes and SDHB immunohistochemistry in 15 cases.

Main Results:

• Common PASS malignancy indicators include high cellularity, tumor cell spindling, and adipose tissue extension.
• Both PASS and GAPP scores demonstrated high sensitivity and negative predictive value, but low specificity and positive predictive value.
• GAPP score exhibited higher specificity than PASS score.

Conclusions:

• GAPP and PASS scores effectively differentiate tumors with low metastatic risk from those with higher risk.
• The specificity of GAPP was found to be superior to PASS.
• Incorporating objective markers like SDHB immunohistochemistry could enhance the specificity of current predictive scoring systems.