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Table of Contents
CASE REPORT
Year : 2019  |  Volume : 30  |  Issue : 5  |  Page : 238-240

Thyrotoxic goiter and asymptomatic thyroid nodule as an initial presentation of clear cell renal cell carcinoma: A report of two cases


1 Department of Urology, Universiti Putra Malaysia, Putrajaya, Malaysia
2 Department of Urology, Hospital Serdang, Putrajaya, Malaysia
3 Pathology Department, Hospital Putrajaya, Putrajaya, Malaysia
4 Cyberjaya University, College of Medical Sciences, Cyberjaya, Selangor, Malaysia

Date of Submission12-Dec-2018
Date of Decision18-May-2019
Date of Acceptance17-Jun-2019
Date of Web Publication24-Oct-2019

Correspondence Address:
Mohd Ghani Khairul-Asri
Department of Urology, Universiti Putra Malaysia, Level 4, Block B, FPSK, 43400 UPM Serdang, Selangor
Malaysia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/UROS.UROS_141_18

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  Abstract 


Thyroid nodule as a metastasis to renal cell carcinoma (RCC) is rarely found. We present two cases – presented with thyroid nodules and diagnosed as metastatic RCC; one patient had thyrotoxic goiter, whereas the second patient presented with asymptomatic thyroid nodule. Subsequently, hemithyroidectomy and total thyroidectomy were performed, respectively. Then, both patients underwent radical nephrectomy for the primary tumor. At present, patients are under regular oncology follow-up, with no evidence of disease recurrence.

Keywords: Metastatic renal cell carcinoma, radical nephrectomy, renal cell carcinoma, thyroid tumor


How to cite this article:
Khairul-Asri MG, Sidhu S, Raja Gopal NS, Azli S, Badawi MA, Hadi S, Fahmy O. Thyrotoxic goiter and asymptomatic thyroid nodule as an initial presentation of clear cell renal cell carcinoma: A report of two cases. Urol Sci 2019;30:238-40

How to cite this URL:
Khairul-Asri MG, Sidhu S, Raja Gopal NS, Azli S, Badawi MA, Hadi S, Fahmy O. Thyrotoxic goiter and asymptomatic thyroid nodule as an initial presentation of clear cell renal cell carcinoma: A report of two cases. Urol Sci [serial online] 2019 [cited 2019 Nov 11];30:238-40. Available from: http://www.e-urol-sci.com/text.asp?2019/30/5/238/269885




  Introduction Top


Renal cell carcinoma (RCC) is the most common cancer which affects the kidney and usually diagnosed incidentally; however, it can present with symptomatic or asymptomatic metastasis.[1] The bone, lung, and lymph nodes are the most common metastatic sites of RCC, whereas metastasis to the thyroid gland is rarely found in clinical practice.[2] Most commonly, thyroid metastasis appears after years of treatment of the primary RCC, whereas presentation with thyroid metastasis before clinically appreciable RCC is quite rare, and almost all thyroid metastases due to RCC are euthyroid.[3] In this report, we present two cases of thyroid metastasis as an initial presentation of asymptomatic RCC. One of the two patients had thyrotoxic goiter, which is extremely rare.


  Case Reports Top


Case 1

A 68-year-old Indian woman with a history of Type 2 diabetes mellitus was also referred to our center for further management of right renal mass. She underwent total thyroidectomy for toxic multinodular goiter with retrosternal extension in different hospital. Preoperative thyroid ultrasound displayed multinodular goiter, which was confirmed by fine-needle aspiration cytology. Thyroid function tests displayed elevated T4 (27.56 pmol/L) and low thyroid-stimulating hormone (TSH) (0.01 mIU/L). After total thyroidectomy, she was commenced on tablet levothyroxine 100 mg once daily that maintained TSH and T4 levels within normal ranges. The histopathological examination revealed nodular hyperplasia with a 3 mm focus of metastatic RCC detected amidst the nodular hyperplasia [Figure 1]. Ultrasound abdomen done postoperatively showed a soft-tissue echogenicity at the upper pole of the right kidney measuring 3.6 cm × 4.5 cm. This was followed by a computed tomography (CT) scan which revealed a heterogeneous solid mass near the upper pole of the right kidney measuring 4.4 cm × 4 cm × 4.8 cm (cT1b, N0, and M0) [Figure 2]. She underwent right laparoscopic nephrectomy, and the histopathological examination of the right kidney showed clear cell RCC, Fuhrman Grade 3 (pT1b); the tumor was predominantly composed of clear cells arranged in alveolar formation and solid sheets with centrally located nuclei and prominent nucleoli. Vascular and ureteric margins were negative for malignancy. There was no lymphovascular invasion or invasion to the renal capsule, renal pelvis, or sinus fat. After the operation, the patient was discharged well with an outpatient surveillance under oncology department.
Figure 1: (a) H and E section shows metastatic renal cell carcinoma detected amidst nodular hyperplasia of the thyroid, (b) the thyroglobulin antibody expressed by the surrounding thyroid tissue, sparing the metastatic renal cell carcinoma

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Figure 2: A contrasted computed tomography showing right renal mass

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Case 2

Another patient, 62-year-old Chinese woman underlying hypertension was referred to our center for further management of left renal mass. Initially, she presented with painless anterior neck swelling for 2 months and denied any obstructive or constitutional symptoms. Ultrasound of the thyroid gland showed two hypoechoic nodules in the left thyroid lobe, largest nodule measured 4.1 cm × 3.8 cm. Ultrasound-guided fine-needle aspiration cytology of the left dominant nodule revealed metastatic clear cell RCC. Subsequently, she underwent left hemithyroidectomy, and the histopathological examination was reported as malignant clear cell epithelial neoplasm in favor of metastatic RCC [Figure 3]. Pre and postoperative thyroid function tests were within the normal range. CT scan of the chest, abdomen, and pelvis was arranged postleft hemithyroidectomy and revealed a large heterogeneous mass in the posteromedial aspect of the upper and mid-poles of the kidney measuring 9.5 cm × 7.5 cm × 7.8 cm [Figure 4]. It was reported as RCC with clinical stage cT2a, N0, and M0. There was no evidence of other distant metastasis. After 4 weeks, we proceeded with left open radical nephrectomy. The histopathological examination of the left kidney displayed Fuhrman Grade 4 malignant cells, arranged predominantly in solid sheets and nests. Some cystically dilated spaces and areas of hemorrhage and necrosis were identified. Ureteric and vascular margins were negative with no invasion to renal pelvis, sinus fat, or perinephric fat. She was discharged well postoperatively and referred to oncology outpatient clinic for further follow-up.
Figure 3: (a) H and E sections show renal cell carcinoma infiltration into the thyroid parenchyma. The renal cell carcinoma arranged in compact nests interspersed with arborizing vasculature, (b) renal cell carcinoma displays positive renal cell carcinoma antibodies

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Figure 4: A contrasted computed tomography showing large left renal mass

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  Discussion Top


RCC is an aggressive tumor which accounts for 2%–3% of all tumors, and up to 30% of patient have metastasis at time of the first diagnosis.[4] Despite rarely metastasize to the thyroid, RCC is the most common nonthyroid malignancy detected in the thyroid gland.[5] Most of the diagnosed thyroid metastasis are reported many years after the initial diagnosis of the RCC with average interval of about 10 years between the radical nephrectomy and the diagnosis of the thyroid metastasis.[3] Presentation with toxic goiter, as in one our cases, is considered extremely rare.

The mechanism by which RCC metastasize to the thyroid is not well understood. As a highly vascular, it was suggested that goiter or thyroiditis might alter the blood flow of the thyroid gland and facilitate the deposition of metastatic cells. On the other hand, other studies reported that there was no difference in the frequency of metastasis in altered thyroid glands versus normal thyroid glands.[3] Molecular and genetic analysis of RCC metastasis to the thyroid might help to understand specific tumor characteristics and predict the prognosis for such cases.

Until now, surgical treatment is the main management suggested for RCC with solitary or oligometastasis.[6] Due to the limited number of cases, the impact of solitary thyroid metastasis on the prognosis cannot be investigated. Furthermore, it is not clear how the time of the diagnosis – either as initial presentation, or many years after the radical nephrectomy – can affect the outcome. Jackson et al. reported a median survival of 30 months for patients who underwent thyroidectomy for their metastasis versus 12 months without thyroidectomy.[3]

Prognostic scoring systems have been developed to define risk groups of patients by combining independent prognostic factors for survival in patients with metastatic RCC. In addition to Memorial Sloan Kettering Cancer Center scoring system for prognostic scoring, International mRCC Database Consortium system is more commonly used in recent studies.[7],[8]

These two cases should alert clinicians to include metastatic RCC in the differential diagnosis of a new thyroid mass. Although usually asymptomatic, RCC metastasis to the thyroid can present as a toxic goiter.


  Conclusion Top


Asymptomatic RCC can present with distant organ metastasis such as thyroid gland. Surgical treatment including metastasectomy and radical nephrectomy is suggested to improve the prognosis; however, long-term follow-up is mandatory for proper outcome assessment.

Declaration of patient consent and ethical statement

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. This manuscript was exempted from IRB because it is a retrospective case report.

Acknowledgment

The authors thank the patients for giving permission for publishing these cases.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Pantuck AJ, Zisman A, Belldegrun AS. The changing natural history of renal cell carcinoma. J Urol 2001;166:1611-23.  Back to cited text no. 1
    
2.
Koul H, Huh JS, Rove KO, Crompton L, Koul S, Meacham RB, et al. Molecular aspects of renal cell carcinoma: A review. Am J Cancer Res 2011;1:240-54.  Back to cited text no. 2
    
3.
Jackson G, Fino N, Bitting RL. Clinical characteristics of patients with renal cell carcinoma and metastasis to the thyroid gland. Clin Med Insights Oncol 2017;11:1-5.  Back to cited text no. 3
    
4.
European Network of Cancer Registries. Eurocim Version 4.0. Lyon, France: European Network of Cancer Registries; 2001.  Back to cited text no. 4
    
5.
Choueiri TK, Motzer RJ. Systemic therapy for metastatic renal-cell carcinoma. N Engl J Med 2017;376:354-66.  Back to cited text no. 5
    
6.
Alt AL, Boorjian SA, Lohse CM, Costello BA, Leibovich BC, Blute ML, et al. Survival after complete surgical resection of multiple metastases from renal cell carcinoma. Cancer 2011;117:2873-82.  Back to cited text no. 6
    
7.
Motzer RJ, Mazumdar M, Bacik J, Berg W, Amsterdam A, Ferrara J. Survival and prognostic stratification of 670 patients with advanced renal cell carcinoma. J Clin Oncol 1999;17:2530-40.  Back to cited text no. 7
    
8.
Heng DY, Xie W, Regan MM, Warren MA, Golshayan AR, Sahi C, et al. Prognostic factors for overall survival in patients with metastatic renal cell carcinoma treated with vascular endothelial growth factor-targeted agents: Results from a large, multicenter study. J Clin Oncol 2009;27:5794-9.  Back to cited text no. 8
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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