Thyroid-like follicular carcinoma of the kidney: one case report and review of the literature.
OBJECTIVES
Thyroid-like follicular carcinoma of the kidney continues to confound the practicing pathologist with its close resemblance to the follicular variant of thyroid carcinoma, as well as other benign and malignant entities. Our goal is to expand the knowledge of this rare renal cell carcinoma subtype, which is morphologically similar to follicular carcinoma of the thyroid but lacks expression of characteristic thyroid immunohistochemical markers such as TTF-1 and thyroglobulin.


METHODS
We evaluated the gross, histologic, immunohistochemical, and fluorescence in situ hybridization (FISH) studies of a new case and performed a comprehensive review of the literature.


RESULTS
The lesion was spongy and well-circumscribed. Microscopically it showed variably sized follicular structures, filled with abundant, deeply eosinophilic, colloid-like material. At the periphery, it displayed areas resembling metanephric adenoma and early stages of nephrogenesis. The tumor cells strongly expressed CK7, PAX-8, PAX-2, vimentin, EMA, and CK19 immunostains. Other markers, such as CD10, RCC, HBME-1, thyroglobulin, and TTF-1, were not immunoreactive. The tumor was negative for trisomy of both 7 and 17 and showed borderline monosomies (losses) of both chromosomes in FISH studies.


CONCLUSIONS
Five years of preoperative observation and lack of recurrence bring further insight into the slow progressive nature of this neoplasm and support a low malignant potential. Proper identification is important to secure adequate treatment and follow-up.
['Dawane|Rahul|R|', 'Grindstaff|Alan|A|', 'Parwani|Anil V|AV|', 'Brock|Timothy|T|', 'White|Wesley M|WM|', 'Nodit|Laurentia|L|']
D018263:Adenocarcinoma, Follicular D014408:Biomarkers, Tumor D002292:Carcinoma, Renal Cell D005260:Female D006801:Humans D007150:Immunohistochemistry D007668:Kidney D007680:Kidney Neoplasms D008875:Middle Aged D009364:Neoplasm Recurrence, Local
Renal cell carcinoma Kidney tumor Thyroid-like follicular carcinoma of kidney