@tdavenport. I understand your worry about information in your pathology report that is difficult to understand. I'm sorry I cannot be more helpful about PTEN loss as I am not a physician or a medical scientist. I'm going to tag @val64 as she is a lab scientist who may be able to explain the term or where to look up more information.

Loss of the PTEN gene is exceptionally common in all of the less dangerous forms of endometrial cancer, as categorized based on gene mutations, as can be seen in this Table:
https://pmc.ncbi.nlm.nih.gov/articles/PMC8005218/table/cancers-13-01478-t002/
The four types of EC they're describing are listed across the top (POLE mutant, MMR deficient, "Non-Specific Molecular Profile" (NSMP), and p53 abnormal.) The percentage of each type that is defective for PTEN is shown in the "Top five recurrent gene mutations" row. For all three types, except the p53 abnormal group, at least 77% of all tumors are defective for PTEN.

So the fact that your tumor has PTEN loss is not something to worry about. It's a characteristic of the vast majority of lower grade ECs.

You didn't mention whether they tested your tumor for MLH1, MSH2, MSH6, and PMS2 or for POLE. In the US, all endometrial tumors are tested for MLH1, MSH2, MSH6, and PMS2, which is the test for MMR deficiency, although they may be waiting for the hysterectomy specimen to do that. As far as I know, it is still very uncommon in the US to test for POLE, although they really should. Apparently they do in Canada now.