Introduction Pleomorphic adenomas (PA) should be surgically resected because of their potential
for malignity, but this is not mandatory for other benign tumors. In the case of intraoperative
pseudocapsule opening, there is a lifelong risk of recurrence. A reliable diagnosis
is currently not possible using CT, MRI or sonography. A preliminary study showed
that PA express SSTR21. The aim of this study is the immunohistochemical (ICH) analysis
of surface receptors of salivary gland tumors for the expression of SSTR2.
Methods In this unicentric retrospective study, all salivary gland tumors that were surgically
resected in our clinic between 03/2016 and 12/2019 were examined using IHC for the
SSTR2. IHC evaluation was performed using the HER2-Mama scale.
Results 354 patients were included (99 PA (27.9%), 255 other tumors). Samples were not available
for 30 tumors. Another 18 samples were not included because they were cysts. IHC analysis
of the remaining 306 tumors (207 non-PA and 99 PA) revealed that the overall percentage
of cells staining for SSTR2 was higher in PA. 42.3% of the PA showed >20% of the cells
showing the SSTR2 compared to only 1.2% of the other tumors. PA was found to exhibit
strong intensity of SSTR2 staining (90.9% ≥ intensity of 2).
Conclusion SSTR2 was strongly expressed in PA. This property may allow radioligated somatostatin
analog PET-CT/MR imaging to be used to diagnose PA among other tumors. In addition,
SSTR positivity could enable peptide receptor radionuclide or somatostatin analogue
therapy in the future.
