A case report of ectopic thyroid adenoma resection by transaxillary non-inflatable endoscopic surgery

Abstract

Introduction and importance

The ectopic thyroid gland is a rare disease in which abnormal migration of the embryonic thyroid germ is thought to be the basis for the formation of the ectopic thyroid gland.

Case presentation

A 37 year old female sought medical attention due to feeling a sensation of swallowing foreign objects, without any other positive symptoms such as pain or difficulty breathing. Preoperative examination revealed a nodule in the left lobe of the thyroid gland and a nodule behind the left lobe. The patient ultimately underwent non-inflatable endoscopic surgery under the axilla to completely remove the tumor located in the suprasternal fossa. Postoperative pathological examination confirmed ectopic thyroid adenoma. The patient's postoperative thyroid function was normal.

Clinical discussion

The diagnosis of ectopic thyroid is difficult due to its highly non-specific histological characteristics and positional changes. However, clinical diagnosis and treatment should not overlook the possibility of ectopic thyroid. On the basis of completely removing the lesion, the transaxillary non-inflatable endoscopic surgery also meets the patient's minimally invasive and aesthetic needs.

Conclusion

The diagnosis of ectopic thyroid is difficult, and through transaxillary non-inflatable endoscopic surgery, the tumor can be completely removed and the patient's aesthetic needs can be met.

Highlights

• •Ectopic thyroid gland can be difficult to diagnose.
• •Principles of ectopic thyroid surgery and treatment.
• •Transaxillary non-inflatable endoscopic surgery allows for complete resection of the tumor and satisfies the aesthetic needs of the patient.

1. Background

An ectopic thyroid gland is very rare and is more common in women, with an overall incidence of about 1 in 100,000 in the population [1]. It is caused by developmental abnormalities during the period when endodermal epithelial cells on the median surface of the primitive pharyngeal intestine proliferate, gradually descends, migrate, and develop, finally settling in the anterior cervical position in the third to fourth week of gestation. Thus, the ectopic thyroid is commonly found near or lateral to the cervical area although it has also been reported in distant locations such as the iris, heart, esophagus, duodenum, gallbladder, liver, adrenal glands, ovaries, and uterus [2,3]. This article describes a case of complete resection of an ectopic thyroid adenoma located in the suprasternal fossa by transaxillary non-inflatable endoscopic surgery. This work has been reported in line with the SCARE 2023 criteria [4].

2. Patient summary

The patient is a 37-year-old woman. Present with a sensation of swallowing a foreign body. No obvious mass was palpated on the neck, and the patient did not have pain, dyspnea, or other discomfort. Neither family nor personal history is worth noting. Thyroid ultrasound showed the presence of a hypoechoic thyroid nodule in the left lobe, TI-RADS class 4a, size approximately 0.33 × 0.39 × 0.69 cm; the left lobe nodule was mixed behind the thyroid gland with a size of approximately 1.56 × 1.56 cm (Fig. 1A). Neck-enhanced computed tomography (CT) indicated a nodule in the left lobe of the thyroid gland and a nodule with a size of about 1.6 × 2.4 cm behind the left lobe of the thyroid gland that was shifted to the right near the esophageal compression (Fig. 1B). Preoperative tests for thyroid function were within normal limits (Fig. 3A). The possible preoperative diagnoses were thyroid tumor, parathyroid tumor, or lymph node metastasis of a thyroid tumor. As the patient was experiencing esophageal compression and there was a suspected malignant nodule in the left lobe of the thyroid gland, surgical resection was recommended. The patient is a young woman with high requirements for appearance. So we used transaxillary non-inflatable endoscopic surgery to remove the lesion.

Fig. 1.

Preoperative imaging results of the patient. A. Cervical ultrasound: a hypoecho of about 0.33 × 0.39 × 0.69 cm in size and regular morphology was found in the lower thyroid part of the left lobe. A range of about 1.56 × 1.56 cm mixed echoes were found behind the thyroid gland in the left lobe, with regular morphology. B. Neck enhanced CT: nodular slightly low-density shadow with a diameter of about 0.6 cm in the posterior part of the left lobe of the thyroid gland, with uneven intensity, with a nodular soft tissue density shadow with a size of about 1.6 × 2.4 cm behind it, with clearly uneven intensity, and compression of the adjacent esophagus to the right (within the blue circle). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3.

Preoperative thyroid function and corresponding antibody tests. A. Preoperative thyroid function. B. Postoperative thyroid function.

The operation showed the presence of gray irregular tissue in the suprasternal fossa behind the left thyroid lobe, fairly close to the tepalum of the left lobe of the thyroid gland, but without parenchymal connection with the thyroid lobe (Fig. 2B, C). After the removal of the left lobe and the mass of the thyroid gland, the mass was found to be approximately 2.5 × 2.0 × 1.5 cm in size, with a complete capsule and several vesicles visible on the surface that were found to contain a gray-yellow jelly. Intraoperative cryosections showed benign thyroid lesions, and the mass was suggestive of adenomatous hyperplastic nodules. Postoperative pathological sections confirmed that the mass represented thyroid adenomatous hyperplastic nodules, and no metastases were found in the central lymph nodes (Fig. 2E-I). The mass was thus diagnosed as an ectopic thyroid adenoma. Thyroid hormone measurements were performed postoperative (Fig. 3B), and the results were normal. The patient recovered well without neck bleeding, facial numbness, or convulsions, and was discharged on the fifth day after surgery.

Fig. 2.

Postoperative pathology image: A. transaxillary surgical incision; B. preoperative image before mass resection; C. postoperative image after mass resection; D. diagram showing the location of the neck mass. E-F. Thyroid nodules in the left lobe: adenomatous hyperplastic nodules, with active follicular epithelial hyperplasia and fibrous tissue hyperplasia in the focal area, as well as cholesterol crystals and hemosiderosis can be seen. G. Mass: thyroid adenomatous hyperplastic nodules, with fibrous tissue hyperplasia in the focal area with calcification. H-I. Lymph nodes in the central region of the neck showed reactive hyperplastic changes, and no malignant lesions were found.

3. Discussion

The thyroid gland is the largest endocrine gland in the human body. It begins to develop in the third to fourth week of pregnancy. The embryonic thyroid germ layer descends from the base of the primitive pharyngeal intestine (located between the back and front two-thirds of the tongue), in the midline, to the area in front of the second to the fourth tracheal ring of the neck. If this descent is abnormal, an ectopic thyroid gland can result. Recent genetic studies suggest that mutations in the transcription factor-encoding genes TITF-1 (Nkx2-1), FOXE1 (TITF-2), and PAX-8 are significantly associated with abnormal migration of the thyroid gland [[5], [6], [7]].

Thyroid tissue that appears outside the normal thyroid position is termed an ectopic thyroid and is divided into two categories, namely, an ectopic thyroid that lacks normal thyroid function and an ectopic thyroid with normal thyroid function. Approximately 90 % of the ectopic thyroid is located at the base of the tongue, with only 10 % in the neck and other locations. The majority of patients with ectopic thyroid are asymptomatic [1,8], and because of their lack of characteristic findings, the disorder can only be identified by radionuclide thyroid scintigraphy, ultrasound, and thyroid function tests, with the diagnosis usually confirmed by histological biopsy [9].

Treatment of an ectopic thyroid depends on its location and size and the presence of symptoms or complications. A non-functional ectopic thyroid accompanied by a normal thyroid gland generally does not require treatment, as it lacks a secretory function and a normal thyroid gland is present. However, removal of the ectopic thyroid can be done if it is too large, accompanied by symptoms, or for aesthetic reasons, without adverse consequences. In the case of a functional ectopic thyroid, because it has normal thyroid secretory functions, resection will likely adversely affect thyroid function, so patients with no obvious symptoms and normal thyroid function are mainly observed and monitored. For patients with surgical guidelines, thyroid function should be monitored preoperatively and postoperatively, thyroid hormone supplementation should be done in time, and long-term postoperative follow-up should be performed [[10], [11], [12]].

In previous reports, cervical incision surgery was often used to remove ectopic thyroid tissue in the neck [13,14]. In our case, the patient was a young female patient with a high demand for beauty, so we used transaxillary non-inflatable endoscopic surgery to remove the lesion. Transaxillary non-inflatable endoscopic surgery can protect the function of the anterior cervical area perfectly, with no numbness or discomfort in the front of the neck and no tracheal skin linkage when swallowing. The surgical incision is less invasive than those used in the transoral and areola approaches, and the cosmetic effect is excellent, although it is more difficult to treat the contralateral gland [[15], [16], [17]]. In this case, the lesion was located in the suprasternal fossa and complete resection was difficult. Through careful separation of the sternal muscles and laparoscopic visual field adjustment, the operation lasted two and a half hours, and we finally completely removed the left lobe of the thyroid gland, the ipsilateral central lymph nodes, and the ectopic thyroid adenoma located in the suprasternal fossa. The complete resection of the lesion also meets the needs of patients for minimally invasive aesthetics. The patient's thyroid function before and after surgery was normal and combined with the diagnostic examination, the patient was ultimately diagnosed with a non-functional ectopic thyroid adenoma and was regularly followed up. Compared with the traditional open surgery, the operation time was increased, but the patient's cosmetic needs were met, and there were no special adverse reactions after the operation, and the patient recovered well and was discharged from the hospital on the fifth day after surgery.

4. Conclusion

The diagnosis of ectopic thyroid is difficult, and for young women, complete resection of the tumor can be achieved through transaxillary non-inflatable endoscopic surgery, which can also meet the aesthetic needs of patients.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

This study was approved by the Ethics Committee of the Third People's Hospital of Mianyang and received a written informed consent form from patients.

Funding

This work was supported by Mianyang Municipal Health Commission (202229).

Author contribution

Data curation: Ling He, and Wei Wang;

Writing – original draft: Ling He, and Wei Wang;

Writing – review and editing: Jian-Feng Sheng.

Guarantor

Jian-Feng Sheng.

Research registration number

Not applicable.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Conflict of interest statement

There is no conflict of interest to declare.