Endocrine Abstracts

According to the 4th edition of the WHO classification of endocrine organ tumors (2017), all pheochromocytomas are classified as malignant tumors (ICD-O code 8700/3). However, in the literature there are no unambiguous data on the significance of clinical and laboratory predictors of the aggressiveness of pheochromocytoma. The aim of the study was to verify possible predictors of pheo-progression using clinical data, the results of laboratory and instrumental examination (including PASS and GAPP scales) of patients with a verified diagnosis of pheochromocytoma.

Material and methods: According to the data of this pilot retrospective study, data were analyzed from 27 patients with pheochromocytoma (16 women, 11 men) aged 22–73 years (median 51 years), who were operated on for the period from 2016 to 2021. 24-hour urine analysis for free metanephrines was determined by high performance liquid chromatography with tandem mass spectrometry with the addition of a preservative. The location and size of the pheochromocytoma was assessed by CT data with the determination of the native HU density. An immunohistochemical study was performed with antibodies to chromogranin A, synaptophysin, Ki-67, followed by an assessment of the potential for malignancy using the PASS and GAPP scales.

Results: There was a strong positive correlation between the PASS and GAPP scales (r=0.720), which is statistically significant (P<0.01). Both scales have a statistically significant positive correlation of mean strength with tumor size (PASS: r=0.382/P=0.049; GAPP: r=0.403/P=0.037). Correlation of these scales with the gender and age of patients, as well as the secretory activity of the tumor, was not revealed. A direct correlation was established between the PASS and GAPP scales and the size of the tumor.

Conclusion: According to our data, tumor size should be considered as a clinical predictor of metastatic potential of pheo, however gender, age, and functional activity of the tumor were not useful.

Keywords: pheochromocytoma; immunohistochemistry; PASS; GAPP.