I had a similar biopsy. Mine was described as "suspicious for neoplasm", and I believe it was described as mainly Hurthle cells with few lymphocytes present. In this case I think "indeterminant" means that the types of cells they see are suspicious, it could be benign or cancerous but it is impossible to tell by the FNA. (Certain types of cancers can be determined by FNA, but if it is follicular or Hurthle cell neoplasms, then genetic testing or surgery is the only way to tell if actually is cancer or not).
Mine was sent off to Afirma genetic testing - there are 3 results possible with the Afirma test 1.) benign, 2.) suspicious, ~50% risk for cancer, and 3.) malignant, greater than 99% risk.
Mine came back as still suspicious after Afirma testing. At this point, there was a very good chance the nodule was benign, but Hurthle cells have gone through some genetic changes that makes it difficult to use Afirma to decide whether it is cancerous or not, so I was expecting it to come back as suspicious. (see info from article below)
I had a thyroid lobectomy removing the lobe that had the suspicious nodule. In my case, the nodule was cancerous (but had not spread anywhere, so surgery was all I needed), but there are studies that suggest that the majority of nodules that show up as suspicious for Hurthle cell neoplasms are not cancerous:
If that link doesn't show up, here is the title: THYROID NODULES Hürthle-Cell Nodules classified as suspicious by the Afirma gene expression classifier had a low cancer rate
and here is some info that is important to know: "The study included patients followed at three tertiary care centers who had HCNs with indeterminate biopsy results reported as suspicious for a Hürthle-cell nodule or with a predominance of Hürthle cells. " AGEC refers to Afirma genetic test.
"A total of 72 out of the 169 patients who had the AGEC were treated based on this test results; among these patients, 45 (63%) had suspicious AGEC results, 26 (36%) had benign results and one was nondiagnostic. Only 6 out of the 43 patients (14%) with suspicious AGEC results who underwent surgery had cancerous nodules. A total of 23 out of the 26 patients with benign AGEC results (88%) were followed clinically; only 3 patients had surgery and all 3 nodules were non-cancerous. "
(above is a summary from: CLINICAL THYROIDOLOGY FOR THE PUBLIC A publication of the American Thyroid Association, the actual research article was published in Clinical Thyroidology in 2015).
The "good new bad news" about this is that even if it still shows up as suspicious on the Afirma test, there is a good chance it is benign, but the only way to actually determine that is benign is to have the nodule removed and pathology done on it (usually a thyroid lobectomy or total thyroidectomy). There is also a chance it will show up as benign on the Afirma testing (36% of cases in that study showed up as benign). For some reason I was absolutely positive mine would come back as suspicious based on this article, but 65 vs 35 doesn't mean it always comes back suspicious (I had a lot of thyroid related anxiety going on at the time, so I was probably being pessimistic with my thinking).
Good luck with your genetic testing - it took about two weeks for me to get the results back on mine. Hopefully yours will come back benign, and if it doesn't, please know that this still doesn't necessarily mean that it is cancer.