Papillary thyroid carcinoma presenting at entopic and ectopic sites: A diagnostic conundrum

Auwal Adamu; Abdulrazak Ajiya; Dauda E Suleiman; Yakubu B Shirama

doi:10.4103/njbcs.njbcs_75_21

CASE REPORT

Year : 2022 | Volume : 19 | Issue : 2 | Page : 161-163

Papillary thyroid carcinoma presenting at entopic and ectopic sites: A diagnostic conundrum

Auwal Adamu¹, Abdulrazak Ajiya², Dauda E Suleiman³, Yakubu B Shirama⁴
¹ Department of Otorhinolaryngology Head and Neck Surgery, Abubakar Tafawa Balewa University Teaching Hospital/Abubakar Tafawa Balewa University, Bauchi, Nigeria
² Department of Otorhinolaryngology, Aminu Kano Teaching Hospital/Bayero University, Kano, Nigeria
³ Department of Histopathology, Abubakar Tafawa Balewa University Teaching Hospital/Abubakar Tafawa Balewa University, Bauchi, Nigeria
⁴ Department of Radiology, Abubakar Tafawa Balewa University Teaching Hospital/Abubakar Tafawa Balewa University, Bauchi, Nigeria

Date of Submission	24-Dec-2021
Date of Decision	21-Feb-2022
Date of Acceptance	28-Feb-2022
Date of Web Publication	23-Nov-2022

Correspondence Address:
Auwal Adamu
Department of Otorhinolaryngology Head and Neck Surgery, Abubakar Tafawa Balewa University Teaching Hospital/Abubakar Tafawa Balewa University Bauchi
Nigeria

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/njbcs.njbcs_75_21

Abstract

Papillary thyroid carcinoma (PTC) mostly occurs within the thyroid gland (entopic site), with its occurrence within an ectopic thyroid tissue being rare comprising less than 1% of all thyroid cancers. The coexistence of PTC in entopic and ectopic sites is even rarer, and differentiating ectopic PTC from a metastatic cervical lymph node may pose a diagnostic conundrum. This report is aimed at highlighting the diagnostic challenges and treatment of this rare condition.

Keywords: Diagnostic dilemma, ectopic thyroid cancer, metastatic lymph node, papillary thyroid carcinoma

How to cite this article:
Adamu A, Ajiya A, Suleiman DE, Shirama YB. Papillary thyroid carcinoma presenting at entopic and ectopic sites: A diagnostic conundrum. Niger J Basic Clin Sci 2022;19:161-3

How to cite this URL:
Adamu A, Ajiya A, Suleiman DE, Shirama YB. Papillary thyroid carcinoma presenting at entopic and ectopic sites: A diagnostic conundrum. Niger J Basic Clin Sci [serial online] 2022 [cited 2023 Jun 10];19:161-3. Available from: https://www.njbcs.net/text.asp?2022/19/2/161/361897

Introduction

Thyroid cancer is the most common endocrine malignancy affecting humans.^[1] Papillary thyroid carcinoma (PTC) is the most common type among thyroid cancers and constitutes about 70%–90% of all thyroid malignancies.^[2],[3],[4] The incidence of PTC has been increasing worldwide over the past three decades.^[2],[3] Most cases of the PTC occur within the thyroid gland, but its occurrence in an ectopic thyroid tissue is rare comprising less than 1% of all thyroid cancers.^[5] The coexistence of PTC in entopic and ectopic locations is even rarer. Notwithstanding, metastatic cervical lymph node from primary PTC may mimic this condition. The nodal metastasis from PTC commonly occurs within the central group of cervical lymph nodes, but metastasis to the lateral cervical lymph node group is also rare.^[4],[6] Against this background, we present a 38-year-old woman with PTC within the thyroid gland (entopic site) and left-sided neck mass (ectopic site). The aim of this report is to discuss the diagnostic challenges and treatment of this rare condition.

Case Report

A 38-year-old woman presented with progressive left-sided neck swelling of 3 years duration. There was no associated neck pain, hoarseness of voice, dysphagia, dyspnea, palpitation, excessive sweating, or heat intolerance. A review of other systems was unremarkable. Examination revealed a left-sided neck swelling which was firm, with irregular surface, mobile, and not attached to the skin or underlying structures. There was no palpable thyroid gland enlargement. Ultrasound scan showed a heterogeneous mass within the muscles of the lateral neck, which measured 4.0 × 3.0 × 2.9 cm in dimensions. An incidental finding of a solitary nodule was also seen within the left thyroid lobe, which measured 19.0 × 17.0 × 14.0 mm in its dimensions. Computed tomography scan showed an oval-shaped encapsulated mixed density mass [Figure 1]a and [Figure 1]b deep to the left sternocleidomastoid muscle. The mass displaced the surrounding muscles, but there was no infiltration into the muscles or the great vessels. No lymph node enlargement was seen within the neck. Fine needle aspiration cytology of the left-sided neck mass showed features suggestive of PTC. Initial diagnosis of malignant left thyroid nodule with metastasis to the lateral cervical lymph node was made. The patient was prepared for surgery: Indirect laryngoscopy, metastatic work up, and baseline blood investigations were all normal. The options of total thyroidectomy with supplementary L-thyroxine for life and subtotal thyroidectomy were explained to the patient, and she opted for the latter. She had subtotal thyroidectomy (excision of the whole left lobe, isthmus, and most part of right lobe), with left neck dissection with excision of the left-sided neck mass. Intraoperatively, the left-sided neck mass was found deep to the sternocleidomastoid, with no connection between it and the thyroid gland. The mass was firm with nodular projections (not in keeping with lymph node) these features made us suspect ectopic thyroid tissue [Figure 2]. All samples were sent for histology, and the following findings were found. The section through the left-sided neck mass showed randomly oriented papillae [Figure 3]a, the cells exhibited nuclear enlargement, overlapping, and optical clear chromatin. Adjacent normal thyroid tissue was also seen [Figure 3]b. The same papillary tumor architecture was seen within the left thyroid nodule. A meticulous review of all the sections through the left-sided neck mass was carried out, but no single lymphoid follicle was found within it. The left-sided neck mass was probably an aberrant ectopic thyroid tissue that underwent a malignant transformation. A final diagnosis of PTC manifesting as left thyroid lobe nodule (entopic) and left-sided neck mass (ectopic) was made. The patient has done well postoperatively, and she is still on follow-up.

Figure 1: Coronal (a) and Axial (b) views of CT scan of the neck showing the lateral neck mass (star)

Click here to view

Figure 2: Intraoperative pictures showing the lateral neck mass with nodular projections

Click here to view

Figure 3: (a) Revealed PTC architecture with randomly oriented papillae. (b) Showed PTC architecture (area with star) and adjacent normal thyroid tissues (area with a triangle). H and E × 100

Click here to view

Discussion

PTC is a malignant tumor with cellular differentiation, and it is the most common among the differentiated thyroid cancers.^[3] PTC is common in females, and it can affect all age groups, but it is more common between the ages of 20 and 50 years with a mean age of 40 years.^[3] Furthermore, PTC has been reported to be a slow-growing tumor that can remain localized for a long time.^[4],[6] This is in agreement with the demography and presentation of our patient.

The usual location of an ectopic thyroid is anywhere along the midline of the neck from the foramen cecum of the tongue to the mediastinum. In rare cases, an ectopic thyroid may occur on the lateral side of the neck.^[5],[7] It has been reported that ectopic thyroid tissue can coexist with the normal thyroid gland and can undergo similar pathological processes as normal thyroid glands such as inflammation and malignant transformations.^[7],[8] Similarly, some authors reported the coexistence of a normal thyroid gland with ectopic thyroid carcinoma in the neck.^[5],[8] However, in this study, we reported the coexistence of PTC in entopic and ectopic sites without any connection between them. It is often difficult based on gross features to distinguish between a metastatic cervical lymph node and malignant ectopic thyroid tissue. However, in this case, malignant ectopic thyroid carcinoma was favored due to the histological appearance seen in the lateral neck mass; it was composed of papillary carcinoma architecture with an area of the remnant of normal thyroid tissue and absence of lymphoid follicle within it [Figure 3]b.

Total thyroidectomy has been the usual treatment of thyroid cancers. However, in recent years, there has been a trend toward more conservative hemithyroidectomy, especially in young patients with unilateral thyroid nodule less than 4 cm.^[9] This is consistent with the treatment offered to our patient. Generally, an evaluation of both patient's clinical condition and tumor factors before surgery helps in determining the extent of the thyroidectomy and the need for neck dissection. It was reported that total thyroidectomy is often indicated for tumors larger than 4 cm, extrathyroidal dissemination, or bilateral tumor. Additional factors that may warrant total thyroidectomy include history of radiation exposure, family history of thyroid cancer, and unfavorable histological features like anaplastic changes.^[9] All these features were absent in our patient. For individuals with low-risk PTC with no poor prognostic characteristics, the evidence for doing a total thyroidectomy rather than a hemithyroidectomy is inconclusive and conflicting.^[10] A careful examination of the literature reveals that while total thyroidectomy reduces the chance of recurrence, hemithyroidectomy may be more cost-effective in the long run considering the cost of L-thyroxine in our environment. In these circumstances, the surgeon should discuss the benefits and disadvantages with the patient, so that he/she can make an informed decision.

PTC has been reported to have a good prognosis, especially for young patients (less than 40 years) with the small solitary nodule. Greater than 98% of these patients may survive up to 10–20 years. Poor prognostic features include stage IV disease, gross local invasion, distant metastases, and age above 45 years.^[2]

Conclusion

The coexistence of PTC in entopic and ectopic locations is rare, and a metastatic cervical lymph node may mimic this condition. Therefore, detailed clinical evaluation and meticulous histological analysis of the tissues are paramount in arriving at an accurate diagnosis.

Declaration of patient consent

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.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Lin P, He Y, Wen DY, Li XJ, Zeng JJ, Mo WJ, et al. Comprehensive analysis of the clinical significance and prospective molecular mechanisms of differentially expressed autophagy-related genes in thyroid cancer. Int J Oncol 2018;53:603-19.
2.	Lloyd RV, Buehler D, Khanafshar E. Papillary thyroid carcinoma variants. Head Neck Pathol 2011;5:51-6.
3.	Abdullah MI, Junit SM, Ng KL, Jayapalan JJ, Karikalan B, Hashim OH. Papillary thyroid cancer: Genetic alterations and molecular biomarker investigations. Int J Med Sci 2019;16:450-60.
4.	Qiu Y, Fei Y, Liu J, Liu C, He X, Zhu N, et al. Prevalence, risk factors and location of skip metastasis in papillary thyroid carcinoma: A systematic review and meta-analysis. Cancer Manag Res 2019;11:8721-30.
5.	Agosto-Vargas YS, Gutiérrez M, Martínez JH, Mangual-Garcia M, Palermo C, Vélez-Maymi S, et al. Papillary thyroid carcinoma: Ectopic malignancy versus metastatic disease. Case Rep Endocrinol 2017;2017:1-3. doi: 10.1155/2017/9707031.
6.	Lim YC, Koo BS. Predictive factors of skip metastases to lateral neck compartment leaping central neck compartment in papillary thyroid carcinoma. Oral Oncol 2012;48:262-5.
7.	Santangelo G, Pellino G, De Falco N, Colella G, D'Amato S, Maglione MG, et al. Prevalence, diagnosis and management of ectopic thyroid glands. Int J Surg 2016;28:S1-6.
8.	Vázquez OR, Silva F, Acosta-Pumarejo E, Marín ML. Ectopic papillary thyroid cancer with distant metastasis. Case Rep Endocrinol 2018:8956712. doi: 10.1155/2018/8956712.
9.	Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. American thyroid association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer. Thyroid 2016;26:1-133. doi: 10.1089/thy. 2015.0020.
10.	Nixon IJ, Ganly I, Patel SG, Palmer FL, Whitcher MM, Tuttle RM, et al. Thyroid lobectomy for treatment of well differentiated intrathyroid malignancy. Surgery 2012;151:571-9.