Ectopic thyroid gland in parotid region: a case report and literature review

Abstract

Objective To explore the clinical characteristics, diagnosis, and treatment of ectopic thyroid gland in the parotid gland area, and to provide clinical ideas for the diagnosis and treatment of ectopic thyroid gland. Methods A case of a normal thyroid gland with ectopic thyroid gland tissue in the parotid gland area in the neck was reported. The male patient was 20 years old. The chief complaint was the discovery of a painless mass gradually increasing under the left earlobe for one month. Clinical examination showed obvious bulging of the tissue under the left earlobe. A strip-shaped mass approximately 3.0 cm long could be palpated. It was soft in texture, with a clear boundary, and located under the skin. The skin was pale red and of normal temperature. The body position movement test was negative. Color Doppler ultrasound of the thyroid gland in the neck showed that the shape and size of the thyroid gland were normal. CT images of the head and neck showed a band-like soft tissue density shadow at the area of the parotid gland behind and below the left earlobe, with a clear boundary. The CT value was approximately 30 HU, and further enhancement yielded no additional findings. The admitting diagnosis was a mass in the left parotid gland area. The tumor was incised using a conventional surgical method for the parotid gland area. During the operation, it was found that the tumor was located under the skin, and the contents were bright-red granulomatous tissue without a capsule and adhesive to the skin tissue. The parotid gland capsule was not involved. After the tumor was completely scraped off, intermittent suturing was performed. The resected tumor was sent for pathological examination. A retrospective analysis of the diagnosis and treatment of this type of case was conducted in combination with a literature review. Results The wound of the patient failed to heal in the first stage after the operation. By applying iodoform gauze for pressurized dressing changed weekly, the wound gradually healed about 2 months later. The postoperative pathological report showed an ectopic thyroid gland in the left parotid gland area. The results of the literature review indicate that ectopic thyroid glands can be partial or complete. In the former, normal thyroid gland tissue exists in the neck, and some thyroid gland tissue appears in other locations, mostly at the base of the tongue and mediastinum. In the latter, the thyroid gland in the neck is absent. Both can present with abnormal thyroid gland function and local compression symptoms, and the symptoms are more obvious in patients with a complete ectopic thyroid gland. Ectopic thyroid glands are mainly diagnosed and differentiated through physical examination and imaging examination. Ectopic thyroid glands occurring subcutaneously in the parotid gland area are extremely rare. Physicians should design personalized treatment plans based on clinical examinations and surgical indications. Conclusion A subcutaneous ectopic thyroid gland in the parotid gland area is rare. For ectopic thyroid gland surgery, a reasonable surgical plan should be designed considering the patient's aesthetic needs and prognosis. Puncture biopsy should be performed when necessary to formulate the surgical plan.

Keywords

• ectopic thyroid gland|parotid gland mass|subcutaneous mass|color b-ultrasound|ct examination|puncture biopsy|surgical resection|case report