Follicular Thyroid Carcinoma Metastatic to the Kidney: Report of a Case with Cytohistologic Correlation

[Rare kidney tumor - thyroid-like follicular carcinoma]

The literature review provides an analysis of a rare malignant tumor of the kidney: thyroid-like follicular carcinoma of the kidney (TLFCK). In morphology, this tumor is extremely similar to thyroid follicular carcinoma, but the immunophenotype of tumor cells is different. TLFCK has an indolent clinical course, rarely metastasizes, and even the development of metastases does not mean an unfavorable prognosis for the patient. The literature review presents the features of the clinical course of the disease, macroscopic, microscopic, immunohistochemical characteristics of the tumor and typical cytogenetic breakdowns. Particular attention is paid to the issues of differential diagnosis of the tumor with other pathological processes that may microscopically resemble TLFCK.

Metastatic thyroid carcinoma mimicking as a primary neoplasia of the kidney: A case report

The unfavorable behavior of primary thyroid carcinoma (PTC) has been revealed by the hematogenous distant metastases in ~20-25% of cases with frequent localizations in lungs and bones, but infrequently in kidney. A 69-year-old male patient was admitted to Department of Human Pathology in Adulthood and Childhood 'G. Barresi', University Hospital G. Martino, (Messina, Italy) for an incidentally detected parenchymal mass involving the right kidney. A partial nephrectomy was done; at the post-surgical examination, a large nodular grayish mass was documented. Microscopically, a diffuse proliferation with solid/follicular pattern with some colloid-filled spaces was appreciable. An intense immunopositivity was revealed for thyroglobulin, thyroid transcription factor-1 (TTF-1), paired-box gene 8 (PAX-8) and cytokeratin 7, while CD10 and renal cell carcinoma marker were negative. A diagnosis of the metastatic thyroid follicular carcinoma localized in the kidney was made. At ultrasound examination, a hyperechoic mass extending from the left thyroid lobe to the isthmus, to which TIR4 diagnostic category according to the Italian reporting system for thyroid cytology was attributed. After thyroid surgical procedure, the final diagnosis of primitive differentiated follicular thyroid carcinoma with foci of poorly differentiated component was made.

Metastases to the Kidney: A Case Report and Review of the Literature

Renal metastases are uncommon in clinical practice, even as autopsy reports much frequent cases în disseminated tumors. Usually multiple and bilateral, they can determine many problems of differential diagnosis in case of solitary renal mass, when a primary kidney neoplasm must be excluded. Main sources are represented by the tumors of the lung, breast, digestive tract, melanomas and lymphomas, but rare cases with other etiology have been reported. Imaging can help to the diagnosis; CT scan, MRI, transabdominal ultrasound and sometimes contrast enhanced ultrasound can be useful. The treatment is individualized by the general status, by other organs involved and by the control of primary tumors; nephrectomy can be made in cases with unsure diagnosis and if primary tumor is controlled.

Whole-genome and transcriptome profiling of a metastatic thyroid-like follicular renal cell carcinoma

Thyroid-like follicular renal cell carcinoma (TLFRCC) is a rare cancer with few reports of metastatic disease. Little is known regarding genomic characteristics and therapeutic targets. We present the clinical, pathologic, genomic, and transcriptomic analyses of a case of a 27-yr-old male with TLFRCC who presented initially with bone metastases of unknown primary. Genomic DNA from peripheral blood and metastatic tumor samples were sequenced. A transcriptome of 280 million sequence reads was generated from the same tumor sample. Tumor somatic expression profiles were analyzed to detect aberrant expression. Genomic and transcriptomic data sets were integrated to reveal dysregulation in pathways and identify potential therapeutic targets. Integrative genomic analysis with The Cancer Genome Atlas (TCGA) data set revealed the following outliers in gene expression profiles: CDK6 (81st percentile), MYC (99th percentile), AR (100th percentile), PDGFRA and PDGFRB (99th and 100th percentiles, respectively), and MAP2K2 (86th percentile). The patient received first-line sunitinib to target PDGFRA and PDGFRB and had stable disease for >6 mo, followed by nivolumab upon progression. To the authors’ knowledge, this is the first reported case of comprehensive somatic genomic analyses in a patient with metastatic TLFRCC. Somatic analyses provided molecular confirmation of the primary site of cancer and potential therapeutic strategies in a rare disease with little evidence of efficacy on systemic therapy.

Nephrectomy for Metastatic Kidney Tumor in Patients with Differentiated Thyroid Cancer: A Report of Two Cases

The occurrence of renal tumors originating from thyroid cancer is extremely rare with a few effective treatments for renal metastases. Here, we report the cases of two patients with differentiated thyroid cancer who underwent nephrectomy for a metastatic kidney tumor. Case 1 was a 74-year-old man who was diagnosed with right kidney tumor 10 years after initial surgery for papillary thyroid cancer (PTC). Right nephrectomy was performed, and the pathology was metastatic PTC. Case 2 was a 68-year-old woman who was diagnosed with left kidney tumor 24 years after surgery for follicular thyroid carcinoma (FTC). Left nephrectomy was performed, and the pathology was metastatic FTC. Nephrectomy for single renal metastasis could be considered a treatment option if the patients' general condition is positive.

Thyroid-Like Follicular Carcinoma of the Kidney in a Patient with Skull and Meningeal Metastasis: A Unique Case Report and Review of the Literature

Thyroid-like follicular carcinoma of the kidney (TLFCK) is an extremely rare subtype of renal cell carcinoma with close resemblance to the well-differentiated thyroid follicular neoplasms. TLFCK has not been included in the 2004 World Health Organization (WHO) classification due to the limited data available. Only 27 cases have been reported in the literature to date. Herein, we report a unique case of TLFCK that presented as a striking skull and meningeal metastasis 5 years after the initial diagnosis; this is the first case of TLFCK with such a novel metastasis pattern. A 68-year-old woman was found to have a right renal lesion using computed tomography (CT) during her regular clinical follow-up visit for bladder cancer, but she exhibited no obvious clinical symptoms. The CT scan showed a 4.4-cm diameter, slightly lobulated soft tissue mass in the right lower kidney, the pathological findings of which showed a TLFCK. Five years later, the patient had progressed to skull and meningeal metastasis. Both the renal tumor and the metastasis lesion were composed almost entirely of follicles with a dense, colloid-like material that resembled thyroid follicular carcinoma. However, no lesion was found in the thyroid gland. The neoplastic epithelial cells were strongly immunoreactive for cytokeratin 7 (and vimentin but negative for thyroid transcription factor-1 and thyroglobulin. This is the first reported case of TLFCK to consist of widespread metastases to the skull and meninges and provides evidence that this rare variant of renal cell carcinoma has uncertain malignant potential and can be more clinically aggressive than previously believed.