Unveiling the enigma: thyroid-like follicular carcinoma of the left kidney Authors Nauman Zafar Department of Urology, Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan Saud Iqbal Pakistan Kidney and Liver Institute and Research Centre Lahore, Pakistan Shujah Muhammad Department of Urology, Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan Nadeem Bin Nusrat Department of Urology, Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan Assad Ur Rehman Department of Urology, Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan Saira Imtiaz Department of Urology, Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan DOI: https://doi.org/10.47391/JPMA.11427 Keywords: Thyroid-like follicular carcinoma of the kidney, Renal cell carcinoma, Metastatic follicular carcinoma of the thyroid, WHO classification Abstract Thyroid-like follicular carcinoma of the kidney (TLFCK) is a rare renal cancer, not aligning with established renal cell carcinoma subtypes. Histologically akin to primary thyroid follicular carcinoma, TLFC poses diagnostic challenges due to absent thyroid immunohistochemistry markers. This case details a 40-year-old army man, previously hypertension-free, presenting with bilateral flank pain and severe haematuria. Imaging revealed a 5.5 × 5 cm calcified lesion in the left kidney, suggestive of renal cell carcinoma (T3aN0Mx). Immunohistochemistry confirmed the diagnosis, with positive Paired box gene 8 (PAX8), Cytokeratin 7 (CK7) and Carbonic anhydrase IX (CAIX) and negative Cluster of differentiation 10 (CD10), Alpha-methyl acyl-CoA racemase (AMACR), Cluster of differentiation 117(CD117), Thyroid transcription factor 1 (TTF1) and thyroglobulin. The tumour was confined to the kidney, with clear margins. Subsequently, signs of metastasis prompted systemic treatment initiation with immunotherapy and tyrosine kinase inhibitors, emphasizing diagnostic intricacies and therapeutic complexities associated with TLFC. Keywords: Thyroid-like follicular carcinoma of the kidney; Renal cell carcinoma; Metastatic follicular carcinoma of the thyroid; WHO classification. Downloads Full Text Article Published 2025-02-23 How to Cite Zafar, N., Iqbal, S., Muhammad , S., Nusrat, N. B., Rehman, A. U., & Imtiaz, S. (2025). Unveiling the enigma: thyroid-like follicular carcinoma of the left kidney. Journal of the Pakistan Medical Association, 75(03), 485–487. https://doi.org/10.47391/JPMA.11427 More Citation Formats ACM ACS APA ABNT Chicago Harvard IEEE MLA Turabian Vancouver Download Citation Endnote/Zotero/Mendeley (RIS) BibTeX Issue Vol. 75 No. 03 (2025): MARCH Section CASE REPORT License Copyright (c) 2025 Journal of the Pakistan Medical Association This work is licensed under a Creative Commons Attribution 4.0 International License.