Journal of Cytology
Home About us Ahead of print Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online:1410
  Print this page  Email this page Small font sizeDefault font sizeIncrease font size


 
 Table of Contents    
CASE REPORT  
Year : 2014  |  Volume : 31  |  Issue : 4  |  Page : 210-212
Fine-needle aspiration cytology of metastatic squamous cell carcinoma thyroid: A rare entity


1 Department of Pathology, Government Medical College and Hospital, Sector 32-A, Chandigarh, India
2 ENT, Government Medical College and Hospital, Sector 32-A, Chandigarh, India

Click here for correspondence address and email

Date of Web Publication10-Feb-2015
 

   Abstract 

Metastasis to the thyroid gland is rare with majority of cases discovered during an autopsy. Clinical presentation with a palpable thyroid or functional disturbances in thyroid is uncommon. We report isolated metastasis of laryngeal squamous cell carcinoma (SCC) to the thyroid gland diagnosed on fine-needle aspiration cytology which is minimally invasive and a preferred preliminary diagnostic modality in palpable thyroid swellings. A diagnosis of extra thyroidal SCC is a diagnosis of exclusion when there is no evidence of a coexistent recognizable primary thyroid cancer and/or molecular signatures suggestive of thyroidal origin.

Keywords: Fine-needle aspiration cytology; metastasis; squamous cell carcinoma; thyroid

How to cite this article:
Kundu R, Punia RS, Mohan H, Handa U, Gupta N. Fine-needle aspiration cytology of metastatic squamous cell carcinoma thyroid: A rare entity. J Cytol 2014;31:210-2

How to cite this URL:
Kundu R, Punia RS, Mohan H, Handa U, Gupta N. Fine-needle aspiration cytology of metastatic squamous cell carcinoma thyroid: A rare entity. J Cytol [serial online] 2014 [cited 2020 Sep 19];31:210-2. Available from: http://www.jcytol.org/text.asp?2014/31/4/210/151135



   Introduction Top


Tumoral metastasis to the thyroid is a rare event. Most of these cases are discovered during an autopsy especially in individuals with widespread tumor dissemination. The incidence ranges from 0.5% to 24% in autopsy series for all histotypes. [1] Clinical presentation with a palpable thyroid or disturbances in thyroid function is uncommon and seen in less than a quarter of cases. [2] The tumors which metastasize to the thyroid include carcinomas of kidney, breast, pancreas, colon, ovary, lung and bladder; and malignant melanoma. [3]

Primary squamous cell carcinoma (SCC) of the thyroid is an extremely rare malignancy with a reported incidence of 0.2-1.1% of all thyroid carcinomas. [4] Therefore, the possibility of metastasis from an occult primary must always be considered and ruled out whenever malignant squamous cells are seen in the thyroid. SCCs metastasizing to the thyroid largely have their origin in the lung, esophagus, and head and neck region.

We report isolated metastasis of laryngeal SCC to the thyroid gland which was picked up on fine-needle aspiration cytology (FNAC) which is minimally invasive and a preferred preliminary diagnostic modality in palpable thyroid swellings.


   Case Report Top


A 45-year-old male presented to the outpatient clinic with a complaint of swelling in front of the neck for 10 years which increased recently over 2 months. He also complained of the recent change in voice. The patient was a chronic smoker for the past 15 years. There was no history of weight loss. On examination, the neck swelling was firm, moved on deglutition and measured 7 cm × 3 cm. The thyroid hormone profile was within normal range. Ultrasonography was not done.

Fine-needle aspiration (FNA) of the thyroid swelling was done using the palpation method by the cytopathologist with a 22-gauge, 4.5-cm long needle without using the handle. Two passes from different sites were taken. Direct smears were air-dried for May-Grόnwald Giemsa staining. Hematoxylin and eosin and Papanicolaou (Pap) staining was done on the smears wet fixed in 95% alcohol. Cell block was also made.

The smears showed sheets, clusters, and scattered malignant squamous cells with moderate anaplasia, hyperchromatic nuclei, and scanty dense cytoplasm [[Figure 1]a and b]. Benign follicular epithelial cells, macrophages, and bare nuclei were also seen. The tumor cells showed orangeophilia on Pap stain [[Figure 1]c]. Cell block preparation showed SCC [[Figure 1]d]. Cytologic diagnosis of SCC likely metastatic was rendered.
Figure 1: (a) The aspirate smear from thyroid showing cluster of malignant squamous cells (block arrow), benign follicular epithelial cells (arrow), macrophages, and bare nuclei (MGG, ×200). (b) Tumor cells with moderate anaplasia, hyperchromatic nuclei, and scanty dense cytoplasm (MGG, ×400). (c) Orangeophilic malignant squamous cells (Pap, 400). (d) Cell block preparation showing keratinizing squamous cell carcinoma (H and E, ×100)

Click here to view


Subsequent to this, the patient underwent computed tomography scan neck which showed a growth in the larynx. The thyroid gland except the right lobe had an altered echo texture. An impression of carcinoma larynx with likelihood of tumor deposits in the thyroid gland was made. A laryngeal biopsy was then taken, and histopathologic examination confirmed the diagnosis of laryngeal SCC.


   Discussion Top


Malignancies metastasizing to the thyroid are uncommon and portend a dismal prognosis. These account for 0.1% of all thyroid nodular lesions investigated by FNA. [5] The plausible reasons for rare metastatic deposits to the thyroid are abundant blood flow through the gland which hinders the seeding of tumor cells, high iodine content, and hyperoxic environment which inhibit the development of metastatic tumor cells. [6] The common primary tumor sites include kidney (33%), lung (16%), breast (16%), esophagus (9%), and uterus (7%). [7] Isolated case reports depicting a large variety of primary sites including pancreas, liver, bile duct, prostate, ovary, placenta, adrenal, and parotid have been reported in the literature. [8]

Metastasis to the thyroid is more commonly an autopsy diagnosis which in some cases can be detected clinically. The patient may present with diffuse thyroid swelling or a nodule, dysphagia, dyspnea, dysphonia, and cough. [3],[9] The indexed case presented with swelling thyroid and dysphonia. Metastatic tumors to the thyroid can easily mimic as primary thyroid cancers. To draw an accurate distinction between them on clinical and radiological assessment alone is not always possible. The thyroid function tests are nonspecific and noncontributory. [8] The diagnosis provided by FNAC in majority of cases is straightforward as the cytomorphology of tumor cells is similar to that of the primary tumor and alien to the more common primary tumors of the thyroid. Some cytologic pointers immediately indicating towards secondary malignancy are the presence of keratin, mucin, melanin, and bile. Information about the history of prior tumor elsewhere, an admixture of normal thyroid follicular cells with tumor cells and absence of papillary or follicular pattern in aspirates also point towards metastasis.

The cytologic differentials of SCC are exuberant squamous metaplasia, papillary and anaplastic carcinomas of thyroid with areas of squamous differentiation and rarely a mucoepidermoid carcinoma. [4] Reactive squamous metaplasia of thyroid follicular epithelial cells has cohesive cell clusters with benign features. There is no mitosis or necrosis. Ancillary markers such as p53, p21, and MIB-I can be used to distinguish between a well-differentiated SCC and squamous metaplasia. [10] A mucoepidermoid carcinoma has an admixture of squamous and mucinous cells.

Cytomorphology can give a correct diagnosis of SCC but not whether primary or secondary. This suffices to carry out a thorough radiological work-up and search for the primary tumor site in metastatic cancers to the thyroid. In the current case, the primary tumor in the larynx was established after the FNA diagnosis which prompted the clinician to search for the primary site. Immunostaining for thyroglobulin or thyroid transcription factor and clinical correlation are mandatory for establishing an unequivocal diagnosis of primary SCC thyroid. [10] A diagnosis of extra thyroidal SCC is a diagnosis of exclusion when there is no evidence of a coexistent recognizable primary thyroid cancer and/or an immunoprofile suggestive of tumor origin in the thyroid.

To conclude, SCC metastasizing to the thyroid gland is uncommon. The differentiation between primary and secondary nature of the neoplasm has both therapeutic and prognostic bearing. The presence of obviously malignant squamous cells in thyroid mandates an extensive search for the primary tumor elsewhere.

 
   References Top

1.
Khandelia BK, Chakraborti S, Rai S, Kini H. Metastatic lesions to thyroid associated with dual primaries: A report of two cases. Thyroid Res Pract 2013;10:111-3.  Back to cited text no. 1
  Medknow Journal  
2.
La Rosa S, Imperatori A, Giovanella L, Garancini S, Capella C. Thyroid metastases from typical carcinoid of the lung differentiating between medullary thyroid carcinoma and neuroendocrine tumor metastasis to the thyroid. Thyroid 2009;19:521-6.  Back to cited text no. 2
    
3.
Karapanagiotou E, Saif MW, Rondoyianni D, Markaki S, Alamara C, Kiagia M, et al. Metastatic cervical carcinoma to the thyroid gland: A case report and review of the literature. Yale J Biol Med 2006;79:165-8.  Back to cited text no. 3
    
4.
Rosa M, Toronczyk K. Fine needle aspiration biopsy of three cases of squamous cell carcinoma presenting as a thyroid mass: Cytological findings and differential diagnosis. Cytopathology 2012;23:45-9.  Back to cited text no. 4
    
5.
Schmid KW, Hittmair A, Ofner C, Tötsch M, Ladurner D. Metastatic tumors in fine needle aspiration biopsy of the thyroid. Acta Cytol 1991;35:722-4.  Back to cited text no. 5
    
6.
Fujita T, Ogasawara Y, Doihara H, Shimizu N. Rectal adenocarcinoma metastatic to the thyroid gland. Int J Clin Oncol 2004;9:515-9.  Back to cited text no. 6
    
7.
Nakhjavani MK, Gharib H, Goellner JR, van Heerden JA. Metastasis to the thyroid gland. A report of 43 cases. Cancer 1997;79:574-8.  Back to cited text no. 7
    
8.
Michelow PM, Leiman G. Metastases to the thyroid gland: Diagnosis by aspiration cytology. Diagn Cytopathol 1995;13:209-13.  Back to cited text no. 8
    
9.
Chung AY, Tran TB, Brumund KT, Weisman RA, Bouvet M. Metastases to the thyroid: A review of the literature from the last decade. Thyroid 2012;22:258-68.  Back to cited text no. 9
    
10.
Booya F, Sebo TJ, Kasperbauer JL, Fatourechi V. Primary squamous cell carcinoma of the thyroid: Report of ten cases. Thyroid 2006;16:89-93.  Back to cited text no. 10
    

Top
Correspondence Address:
Reetu Kundu
Department of Pathology, Government Medical College and Hospital, Sector 32-A, Chandigarh - 160 030
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9371.151135

Rights and Permissions


    Figures

  [Figure 1]

This article has been cited by
1 Metastatic squamous cell carcinoma in autotransplanted thyroid: A diagnostic dilemma
Varuna Mallya,Shubhra Narayan,Shyama Jain
Indian Journal of Pathology and Microbiology. 2018; 61(3): 399
[Pubmed] | [DOI]



 

Top
 
 
  Search
 
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  


    Abstract
   Introduction
   Case Report
   Discussion
    References
    Article Figures

 Article Access Statistics
    Viewed1750    
    Printed43    
    Emailed0    
    PDF Downloaded100    
    Comments [Add]    
    Cited by others 1    

Recommend this journal