Journal of Cytology
Home About us Ahead of print Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online:417
  Print this page  Email this page Small font sizeDefault font sizeIncrease font size


 
 Table of Contents    
CASE REPORT  
Year : 2014  |  Volume : 31  |  Issue : 1  |  Page : 53-56
Extramedullary plasmacytoma of thyroid - a mimicker of medullary carcinoma at fine needle aspiration cytology: A case report


Department of Pathology, MVJ Medical College and Research Hospital, Bangalore, Karnataka, India

Click here for correspondence address and email

Date of Web Publication15-Apr-2014
 

   Abstract 

A rare case of extra medullary plasmacytoma (EMP) of thyroid gland in a 60 year old male, occurring against a background of Hashimoto's thyroiditis is reported. The fine needle aspiration cytology (FNAC) initially done as an outpatient procedure, showed atypical epithelial cells on a background of amyloid. Considering these findings we gave a diagnosis of medullary carcinoma. Histology of the total thyroidectomy specimen showed an extensive infiltration of neoplastic plasma cells against a background of Hashimoto's thyroiditis, with a bizarre Hurthle cell change. Immunohistochemistry on the histology sections confirmed the diagnosis of solitary plasmacytoma of thyroid against a background of Hashimoto's thyroiditis.

Keywords: Extramedullary plasmacytoma; fine needle aspiration cytology (FNAC); medullary carcinoma; thyroid

How to cite this article:
Bhat V, Shariff S, Narayana Reddy RA. Extramedullary plasmacytoma of thyroid - a mimicker of medullary carcinoma at fine needle aspiration cytology: A case report. J Cytol 2014;31:53-6

How to cite this URL:
Bhat V, Shariff S, Narayana Reddy RA. Extramedullary plasmacytoma of thyroid - a mimicker of medullary carcinoma at fine needle aspiration cytology: A case report. J Cytol [serial online] 2014 [cited 2019 Jun 26];31:53-6. Available from: http://www.jcytol.org/text.asp?2014/31/1/53/130710



   Introduction Top


Solitary plasmacytoma of the thyroid is an uncommon neoplasm constituting 1.4% of the extramedullary plasmacytomas (EMPs). The patients are often middle-aged to older adults, with a slight male predominance. [1],[2] There are many reported cases of solitary plasmacytomas of the extrathyroidal sites diagnosed on fine needle aspiration cytology (FNAC) in literature. [3],[4] A diagnosis of solitary plasmacytoma of the thyroid made during FNAC, however, to the best of our knowledge, is rare and unique. [4] The present case illustrates the difficulty in arriving at an FNAC diagnosis of solitary plasmacytoma of the thyroid, due to the presence of atypical Hurthle cells and the associated amyloid in the tumor.


   Case Report Top


A 60-year-old male presented with a neck mass, hoarseness of voice, and dysphagia of a three-month duration. On clinical examination the thyroid gland was diffusely enlarged, more prominent on the right side, firm, and painless. The thyroid profile showed hypothyroidism. An ultrasound examination showed hypoechoic areas in both lobes suggestive of a space-occupying lesion.

The FNAC revealed a cellular aspirate composed of cells arranged in numerous acini, loose clusters, pseudopapillae, as well as singly dispersed [Figure 1]a. The cells were round to ovoid, with enlarged nuclei and fine chromatin. Many cells showed nuclear grooves as well as marked anisonucleosis, with occasional intranuclear cytoplasmic inclusions [Figure 1]c. The cytoplasm was abundant, pink, and granular in most of the cells [Figure 1]b. The background showed a few lymphocytes and spindle-shaped cells. Occasional multinucleate giant cells were observed. A pink amorphous acellular material was identified as large blobs and stained positive for Congo red [Figure 1]d. It showed an apple green birefringence on polarising microscopy.
Figure 1:

Click here to view


A possibility of an epithelial neoplasm, either medullary carcinoma (pleomorphic variant) or a follicular variant of papillary carcinoma was given. This was due to the presence of pleomorphic epithelial cells arranged in groups, acini, and papillaroid structures. However, due to the associated amyloid, a strong possibility of medullary carcinoma over papillary carcinoma was considered. Based on this diagnosis, the patient underwent total thyroidectomy. Gross examination of the thyroidectomy specimen showed the right lobe to be with an isthmus measuring 7 5 4 cm and the left lobe measuring 5 4 3 cm. The cut surfaces of both were nodular and fleshy in appearance [Figure 2]a.
Figure 2:

Click here to view


Histopathology: The multiple sections studied, revealed diffuse atypical plasma cells in sheets effacing the normal thyroid parenchyma [Figure 2]b. The intervening areas and thyroid tissue at the periphery showed Hashimoto thyroiditis, with extensive oncocytic change and bizarre nuclear changes. Numerous lymphoepithelial lesions were also noted, with follicular colonization of acini by lymphocytes. Amorphous material, consistent with an amyloid, was identified amidst the neoplastic cells. A diagnosis of plasmacytoma of the thyroid gland was made on histology. A close differential considered on histology was marginal zone lymphoma with extensive plasma cell differentiation. Immunohistochemistry revealed plasmacytoid cells with diffuse positivity for CD138 [Figure 2]c, and also cytoplasmic positivity for the Kappa light chain. The tumor cells were negative for CD19 [Figure 2]d and CD20. On the basis of immunohistochemistry a final diagnosis of extramedullary solitary plasmacytoma (ESP) of the thyroid was made, after the workup was found to be negative for multiple myeloma.


   Discussion Top


Extramedullary plasmacytoma is a rare lesion. [1] A diagnosis of this neoplasm by FNAC has been made at extrathyroidal sites even without the help of immunohistochemistry. [3],[4] The present case is an example of solitary plasmacytoma of the thyroid, which was diagnosed, after FNAC, as a medullary carcinoma, for various reasons outlined below. The needle had sampled predominantly follicular epithelial cells from the periphery of the lesion, which represented changes of Hashimoto thyroiditis (the background in the aspirate showed mononuclear cells, which are predominantly lymphocytes). The predominant component of the aspirate constituted Hurthle cell clusters with bizarre nuclear morphology (mistaken for carcinoma). Some granularity of the cytoplasm and abundant acellular material, which was positive for an amyloid stain, suggested a diagnosis of medullary carcinoma on the aspirate. The neoplastic plasma cells did not constitute the component of the aspirate.

Fine Needle Aspiration Cytology, as outlined in this case, emphasises the limitation of being a diagnostic tool in all thyroid malignancies. A similar case of solitary plasmacytoma of the thyroid has been documented in literature by Bourtsos et al.,[5],[6] who have also demonstrated this pitfall in aspiration cytology diagnosis. Hurthle cells are notorious mimics of malignant cells. They are known to show atypical nuclear changes and hyperchromasia and this has been well-documented in literature. [7],[8] Nuclear grooves are also a feature of Hurthle cells. [8] Most probably, multiple aspirations could have avoided this misinterpretation, but even so, the presence of amyloid in the aspirate associated with some epithelial cells tilted the diagnosis toward a medullary carcinoma.

Bourtsos et al.[5] have emphasized that EMP should be considered in the differential diagnosis of a neck mass that yields discohesive cells associated with amyloid-like material. They made a diagnosis of medullary carcinoma due to the presence of plasmacytoid tumor cells with an amyloid in the background. The present authors mistook Hurthle cells for cells of a pelomorphic variant of medullary carcinoma. The confusion toward malignancy was compounded due the presence of intranuclear inclusions in these cells as well as grooves. Similarly Ridal et al.[9] diagnosed a case of EMP as lymphoplasmacytic lymphoma on cytology. Sarin et al.[10] reported five cases of EMPs on cytology and observed plasmacytoid cells with varying pleomorphisms, bi- and multinucleation, and mitotic figures. All these features posed a diagnostic challenge for them on cytological evaluation.

At histology, although plasmacytoma was considered as a diagnosis, the other close differential was marginal zone lymphoma, with extensive plasma cell differentiation, which was the more common occurrence in the thyroid, as compared to plasmacytomas. [6],[11] On immunohistochemistry, the plasmacytomas were negative for CD45, CD19, and CD 20, and strongly positive for CD138. [12] Marginal zone lymphomas were, on the contrary, positive for CD45, CD19, and CD20, and would show positivity for CD138, depending on the plasma cell differentiation. The present case was strongly positive for CD138, with light chain restriction for kappa chains, which favored a diagnosis of plasmacytoma.

In conclusion, EMP of the thyroid can be diagnosed on cytology with multiple aspirations, to avoid sampling error and to arrive at the right diagnosis. Amyloid-like material can be associated with this type of tumor and not necessarily be a component of medullary carcinoma alone. The other differentials like lymphoproliferative lesions and plasmacytomas must be kept in mind in the setting of autoimmune thyroiditis, which can be diagnosed on cytology.

 
   References Top

1.Fletcher CD. Thyroid tumours. In: Diagnostic Histopathology of Tumors. 3 rd ed. China: Churchill Livingstone Elsevier; 2007. p. 1051.  Back to cited text no. 1
    
2.Alexiou C, Kau RJ, Dietzfelbinger H, Kremer M, Spiess JC, Schratzenstaller B, et al. Extramedullary plasmacytoma: Tumor occurrence and therapeutic concepts. Cancer 1999;85:2305-14.  Back to cited text no. 2
    
3.Saad R, Raab S, Liu Y, Pollice P, Silverman JF. Plasmacytoma of the larynx diagnosed by fine- needle aspiration cytology: A case report. Diagn Cytopathol 2001;24:408-11.  Back to cited text no. 3
    
4.Meccawy AA. Plasmacytoma of the thyroid gland: Case report and review of the literature. JKAU Med Sci 2010;17:83-92.  Back to cited text no. 4
    
5.Bourtsos EP, Bedrossian CW, De Frias DV, Nayar R. Thyroid plasmacytoma mimicking medullary carcinoma: A potential pitfall in aspiration cytology. Diag Cytopathol 2000;23:354-8.  Back to cited text no. 5
    
6.Kovacs CS, Mant MJ, Nguyen GK, Ginsberg J. Plasma cell lesions of the thyroid: Report of a case of solitary plasmacytoma and a review of the literature. Thyroid 1994;4:65-71.  Back to cited text no. 6
    
7.Jayaram G. Problems in the interpretation of hürthle cell populations in fine needle aspirates from the thyroid. Acta Cytol 1983;27:84-5.  Back to cited text no. 7
[PUBMED]    
8.Siddaraju N, Wilfred CD, Singh N, Murugan P, Verma SK. Fine needle aspiration cytology of the thyroid following carbimazole therapy in Graves′ disease: A case report. Internet J Endocrinol 2008;4:2.  Back to cited text no. 8
    
9.Ridal M, Ouattassi N, Harmouch T, Amarti A, Alami MN. Solitary extramedullary plasmacytoma of the thyroid gland. Case Rep Otolaryngol 2012; 2012:282784. doi: 10.1155/2012/282784. Epub 2012 Oct 9.  Back to cited text no. 9
    
10.Sarin H, Manucha V, Verma K. Extramedullary plasmacytoma, a report of five cases diagnosed by FNAC. J Cytopathol 2009;20:328-31.  Back to cited text no. 10
    
11.Aihara H, Tsutsumi Y, Ishikawa H. Extramedullary plasmacytoma of the thyroid, associated with follicular colonization and stromal deposition of polytypic immunoglobulins and major histocompatibility antigens possible categorization in MALT lymphoma. Acta Pathol Jpn 1992;42:672-83.  Back to cited text no. 11
    
12.Seegmiller AC, Xu Y, McKenna RW, Karandikar NJ. Immunophenotypic differentiation between neoplastic plasma cells in mature B-cell lymphoma vs plasma cell myeloma. Am J Clin Pathol 2007;127:176-81.  Back to cited text no. 12
    

Top
Correspondence Address:
Vidya Bhat
Department of Pathology, MVJ Medical College and Research Hospital, Dandupalaya, Kolathur(P), Hoskote, Bangalore - 562 114, Karnataka
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9371.130710

Rights and Permissions


    Figures

  [Figure 1], [Figure 2]

This article has been cited by
1 Sonography of diffuse thyroid disease
Hok Yuen Yuen,Ka Tak Wong,Anil Tejbhan Ahuja
Australasian Journal of Ultrasound in Medicine. 2016; 19(1): 13
[Pubmed] | [DOI]
2 Synchronous Thyroid Involvement in Plasma Cell Leukemia Masquerading as Hashimotoæs Thyroiditis: Role of Ancillary Cytology Techniques in Diagnostic Workup
Ashwani Tandon,T. Roshni Paul,Rekha Singh,A. M. V. R. Narendra
Endocrine Pathology. 2015; 26(4): 324
[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
    Viewed1529    
    Printed44    
    Emailed1    
    PDF Downloaded125    
    Comments [Add]    
    Cited by others 2    

Recommend this journal