Metastasised renal cell carcinoma after 19 years - 1265081

In 1995 I had a T2 Fuhrman Grade 2 renal cell carcinoma and my left kidney was removed with no evidence that the tumour had moved elsewhere and with no radiation or chemo. I was checked regularly until 2003 when I was given a clearance. Earlier this year a nodule appeared on my thyroid and at the beginning of July the left side of my thyroid was removed and the pathology revealed it was renal cell carcinoma. Here is the pathology report

SPECIMEN: LEFT LOBE THYROIDECTOMY - STITCH SUPERIOR POLE (pot)
MACRO:
Received is a thyroid lobe measuring 60mm in length x 35mm x 45mm.
There is a stitch marking superior aspect. The specimen weighs 48g, the
external surface has a lobular appearance. The external surface is
inked blue. The specimen is bisected. There is a well circumscribed
nodule within measuring 40 x 38mm, it has a solid to cystic appearance
with a soft interior (a photograph of the bisected specimen is
attached). The nodule is located on the middle to inferior pole of the
thyroid lobe. The specimen is serially sliced.
A-E-1M Sections through the solid nodule
F-1M Normal looking thyroid
AA-A1M Extra blocks through solid nodule

MICRO:
The sections show thyroid partly replaced by a tumour with clear
cytoplasm forming follicular and solid structures. The lesion has an
invasive profile with frequent area of lymphovascular space invasion.
The tumour is negative for TTF1 and thyroglobulin, but positive for PAX
8 and CD10. The tumour is negative for CK 7 and CK20 and focally
positive for EMA. The morphologic appearances and immunophenotype would
be consistent with metastatic renal cell carcinoma. Clinical
correlation is required.
DIAGNOSIS:
LEFT LOBE THYROIDECTOMY: METASTATIC RENAL CELL CARCINOMA

I am waiting for a CT scan but everyone seems very surprised that this has ended up in my thyroid at this late point in time and does this mean that even if no other tumours are found I can still have potential cancer cells?