Journal of Cytology
Home About us Ahead of print Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online:429
  Print this page  Email this page Small font sizeDefault font sizeIncrease font size


 
CASE REPORT Table of Contents   
Year : 2010  |  Volume : 27  |  Issue : 1  |  Page : 22-25
Critical appraisal of FNAC in the diagnosis of primary papillary carcinoma arising in thyroglossal cyst: A case report with review of the literature on FNAC and its diagnostic pitfalls


Department of Pathology, Lady Hardinge Medical College, New Delhi, India

Click here for correspondence address and email

Date of Web Publication23-Jul-2010
 

   Abstract 

The incidence of primary papillary carcinoma arising in thyroglossal cyst is rare and occurs in <1% of thyroglossal cysts. Even rarer is its diagnosis by pre-operative fine needle aspiration cytology (FNAC). Only 15 such cases diagnosed by FNAC have been previously reported in the literature. In this article, cytomorphology of the current case is presented along with a review of the literature on FNAC and its diagnostic pitfalls.

Keywords: Papillary carcinoma; thyroglossal cyst; FNAC

How to cite this article:
Agarwal K, Puri V, Singh S. Critical appraisal of FNAC in the diagnosis of primary papillary carcinoma arising in thyroglossal cyst: A case report with review of the literature on FNAC and its diagnostic pitfalls. J Cytol 2010;27:22-5

How to cite this URL:
Agarwal K, Puri V, Singh S. Critical appraisal of FNAC in the diagnosis of primary papillary carcinoma arising in thyroglossal cyst: A case report with review of the literature on FNAC and its diagnostic pitfalls. J Cytol [serial online] 2010 [cited 2019 Dec 14];27:22-5. Available from: http://www.jcytol.org/text.asp?2010/27/1/22/66697



   Introduction Top


Thyroglossal duct cyst is the most common nonodontogenic cyst of the adult population, presenting as midline neck swellings. The incidence of papillary carcinoma arising in the thyroglossal duct cyst is rare (<1%). Approximately 150 cases of papillary carcinoma arising in the thyroglossal duct cyst have previously been reported in the literature. [1],[2] There are very few case reports of these cases diagnosed on fine needle aspiration cytology (FNAC). [1],[3],[4],[5],[6],[7],[8] Thyroglossal duct cyst carcinomas are usually asymptomatic and not suspected preoperatively in most instances; hence, the need for careful pathological examination of these cysts. In this article, cytological features of the present case are described along with diagnostic pitfalls and review of the literature on FNAC.


   Case Report Top


A 22-year-old asymptomatic female presented to the surgical outpatient department with a history of midline neck swelling of two years duration. There was no history of prior radiation. On examination, a well-circumscribed, painless, firm, fluctuant, 2 Χ 2 cm mass in the midline of the neck at the level of the hyoid was found. It showed vertical movement on deglutition. A clinical diagnosis of solitary thyroid nodule was made. There was also right submandibular lymph node enlargement (approx 1.5 cm in diameter). The patient was subsequently referred for FNAC.


   Cytology and Histology Top


Giemsa and PAP-stained highly cellular FNAC smears were composed of big papillary clusters having a fibrovascular core [Figure 1] and few monolayered sheets of follicular epithelial cells. Few cells showed intranuclear cytoplasmic inclusions [Figure 2] and nuclear grooving in the background of scant colloid and many cyst macrophages. Individual cells were round to cuboidal, with a moderate amount of well-defined cytoplasm and single nuclei. In view of the above findings, diagnosis of papillary carcinoma of the thyroid was suggested. Ultrasonography, computed tomography (CT) scan and biopsy of the thyroid were advised. FNAC smears from the right submandibular lymph node revealed a reactive lymph node. Ultrasound of the neck revealed an unremarkable thyroid and a cystic lesion measuring 2 Χ 1 cm, separate from the thyroid. On a thyroid scan, both lobes of the thyroid and isthmus showed normal uptake. The cyst did not show any uptake. There were no cold spots in the thyroid. At the time of neck exploration, a small cystic mass measuring 2 Χ 1 cm and attached to the hyoid bone was found. The thyroid gland was found to be unremarkable.

Hence, preoperative diagnosis of thyroglossal cyst was made and Sistrunk's operation was performed.

The cyst was resected and sent for histopathological examination. Gross examination showed a small cystic mass measuring 2 Χ 1 cm, with an attached part of hyoid bone and skeletal muscle. Cut-section of the cyst showed multiple small friable papillary projections filling the entire cyst. Microscopically, the cyst showed multiple branching papillae with a thin fibrovascular core projecting into its lumen [Figure 3]. The papillae were lined by cuboidal to flattened epithelial cells. The cells showed ground glass nuclei, with few showing intranuclear cytoplasmic inclusions and grooves [Figure 4]. The cyst wall showed infiltration by the tumor. The adjacent thyroid gland was unremarkable. The hyoid bone and skeletal muscle were uninvolved. Hence, the final diagnosis of primary papillary carcinoma of thyroglossal duct cyst was made.


   Discussion Top


Thyroglossal duct cyst is the most common nonodontogenic cyst, prevalence being 7% of the adult population. [1] Carcinomas arising in the thyroglossal duct cyst are generally of two types: thyrogenic carcinoma and squamous carcinoma. The thyrogenic carcinoma most often arises from thyroembryonic rests in the duct or cyst and the squamous carcinoma arises from the metaplastic columnar epithelium. [9]

Incidence of papillary carcinoma arising in the thyroglossal duct cyst is <1%, and it is usually seen in younger women, with a sex ratio of 1.5:1. [1],[9] This patient was a 22-year-old female.

Literature reveals 15 cases of preoperative FNAC of the thyroglossal duct cysts with papillary carcinoma [Table 1]. Nine of the 15 cases were diagnosed as papillary thyroid carcinoma. [1],[3],[4],[5],[6],[7],[10],[11],[12] Only four cases were reported as thyroglossal duct cyst papillary carcinoma. [8],[13],[14],[15] Two case reports were inconclusive. [16],[17] Most of the cases on FNAC belonged to the age group of 21-65 years.

The cytomorphological features on FNAC have been described by few authors. Some considered diagnosis of papillary thyroid carcinoma on the basis of papillary fragments, while others also described intranuclear pseudoinclusions and multinucleated giant cells. [5],[6],[7],[12] The diagnosis of thyroglossal duct cyst was made on the basis of macrophages and benign epithelial cells. [8],[13],[14] None of the case was diagnosed as papillary carcinoma arising in the thyroglossal duct cyst.

Although diagnostic criteria of papillary carcinoma thyroid and thyroglossal duct cyst on FNAC have been defined, diagnostic pitfalls in giving accurate diagnosis of papillary carcinomas arising in the thyroglossal duct cyst are very common. Major criteria are high cellularity, papillary formations, cells with enlarged nuclei showing anisonucleosis and powdery chromatin and definite nucleoli. Intranuclear pseudoinclusions and grooves are significant. Psammoma bodies, multinucleate giant cells and ropy colloid are variably present. [1]

FNAC yielded correct results in only 50-66% of cases. [1],[14] The false-negative result on FNAC was due to cystic fluid that was aspirated, leading to hypocellularity from dilution due to cystic contents. [1] Hence, diligent search is a must to diagnose malignant cells. Also, as cystic fluid is often the initial specimen obtained during FNAC of papillary carcinomas and thyroglossal duct cysts, repeat aspirate is important to rule out any residual mass.

Another pitfall in the diagnosis is locating the origin of the tumor by cytological testing alone. In cases of solitary thyroid nodule, entity of the thyroglossal cyst must also be kept in mind and on finding malignancy on FNAC, CT scan or ultrasound should be advised to decide the origin. This can prevent thyroidectomy and its complications.

FNAC also lacks in finding cyst wall infiltration by tumor cells. It is important to quote cyst wall infiltration in the diagnosis as the treatment and prognosis depend on this. If the cancer has not invaded beyond the cyst wall, simple complete excision of the cyst using the Sistrunk's procedure is adequate. [18] If the cancer has invaded beyond the cystic wall, a total or subtotal thyroidectomy is recommended. [1]

Hence, location of the target lesion, careful searching for malignant cells and repeat FNAC are the key to successful diagnosis. Prognosis of papillary carcinomas is good, whether it occurs in the thyroglossal duct cyst or in the thyroid proper, but frequency of lymph node metastasis is lower in papillary carcinomas arising in the thyroglossal duct cyst than that arising in the thyroid proper. [1]

This case is reported in view of the rarity of pre-operative FNAC diagnosis of this entity and to highlight the diagnostic pitfalls and importance of FNAC to plan a proper surgical management.

 
   References Top

1.Yang YJ, Haghir S, Wanamaker JR, Powers CN. Diagnosis of papillary carcinoma in a thyroglossal duct cyst by fine-needle aspiration biopsy. Arch Pathol Lab Med 2000;124:139-42.  Back to cited text no. 1      
2.Tehrani AN, Karimi YAR, Kazemi M. Primary papillary carcinoma in thyroglossal duct cyst. Acta Medica Iranica 2007;45:236-8.  Back to cited text no. 2      
3.Kini SR, Millet JM, Smith-Purslow MJ. Unusual and uncommon encounters in thyroid aspirates. Acta Cytol 1986;30:571.  Back to cited text no. 3      
4.Kimberley B, Cohen J, Posalsky I. Papillary thyroid carcinoma within a thyroglossal duct cyst. Arch Otol Head Neck Surg 1988;113:206-8.  Back to cited text no. 4      
5.Pitts WC, Tani EM, Skoog L. Papillary carcinoma in fine needle aspiration smears of a thyroglossal duct lesion. Acta Cytol 1988;32:599-661.  Back to cited text no. 5      
6.Prasad ML, Rangaswamy M, Kumar N, Shukla NK. Papillary carcinoma of a thyroglossal duct remnant with Hashimoto's thyroiditis. Ear Nose Throat J 1990;69:358-60.  Back to cited text no. 6      
7.Kashkari S. Identification of papillary carcinoma in a thyroglossal cyst by fine-needle aspiration biopsy. Diagn Cytopathol 1990;6:267-70.  Back to cited text no. 7      
8.Chen KT. Cytology of thyroglossal cyst papillary carcinoma. Diagn Cytopathol 1993;9:318-21.  Back to cited text no. 8      
9.Srinivasan R, Ranjini K, Vadhiraja BM. Primary papillary carcinoma of the thyroglossal duct cyst - a case report. Indian J Pathol Microbiol 2005;48:228-30.  Back to cited text no. 9      
10.Katz AD, Hachigian M. Thyroglossal duct cysts. A thirty year experience with emphasis on occurrence in older patients. Am J Surg 1987;155:741-4.  Back to cited text no. 10      
11.Martνn-Pιrez E, Larraρaga E, Marrσn C, Monje F. Primary papillary carcinoma arising in a thyroglossal duct cyst. Eur J Surg 1997;163:143-5.  Back to cited text no. 11      
12.Kennedy TL, Whitaker M, Wadih G. Thyroglossal duct carcinoma: a rational approach to management. Laryngoscope 1998;108:1154-8.  Back to cited text no. 12      
13.Hilger AW, Thompson SD, Smallman LA, Watkinson JC. Papillary carcinoma arising in a thyroglossal duct cyst: a case report and literature review. J Laryngol Otol 1995;109:1124-7.  Back to cited text no. 13      
14.Bardales RH, Suhrland MJ, Korourian S, Schaefer RF, Hanna EY, Stanley MW. Cytologic findings in thyroglossal duct carcinoma. Am J Clin Pathol 1996;106:615-9.  Back to cited text no. 14      
15.Vera-Sempere F, Tur J, Jaιn J, Perolada JM, Morera C. Papillary thyroid carcinoma arising in the wall of a thyroglossal duct cyst. Acta Otorhinolaryngol Belg 1998;52:49-51.  Back to cited text no. 15      
16.Pacheco-Ojeda L, Micheau C, Stafford N, Marandas P, Luboinski B, Martinez AL. Papillary carcinoma in thyroglossal duct remnants. Eur Arch Otorhinolaryngol 1991;248:268-70.  Back to cited text no. 16      
17.Silverman PM, Degesys GE, Ferguson BJ, Bierre AR. Papillary carcinoma in a thyroglossal duct cyst: CT findings. J Comput Assist Tomogr 1985;9:806-8.  Back to cited text no. 17      
18.Heshmati HM, Fatourechi V, Heerden JAV, Hay ID, Goellner JR. Thyroglossal duct cyst carcinoma: Report of 12 cases. Mayo Clin Proc 1997;72:3.  Back to cited text no. 18      

Top
Correspondence Address:
Vandana Puri
104, HSB, Lady Hardinge Medical College, New Delhi
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9371.66697

Rights and Permissions


    Figures

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

  [Table 1]

This article has been cited by
1 Fine needle aspiration cytology as the primary diagnostic tool in thyroid enlargement
Sengupta, A. and Pal, R. and Kar, S. and Zaman, F.A. and Sengupta, S. and Pal, S.
Journal of Natural Science, Biology and Medicine. 2011; 2(1): 113-118
[Pubmed]



 

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
    Cytology and His...
    Discussion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed2966    
    Printed149    
    Emailed0    
    PDF Downloaded179    
    Comments [Add]    
    Cited by others 1    

Recommend this journal