A Report About a 23-year-old Young Mother Suffering From Rare Insular Thyroid Carcinoma

Insular carcinoma of thyroid (ICT) is a rare malignant tumor with poor differentiation of the thyroid , most patients are middle-aged and elderly women. Here is a report of a case involving a young woman suffering from insular thyroid carcinoma. This report is about a 23-year-old young mother who already has three children of hers. she accidentally discovered a left neck mass with slight pain from local compression about half a year ago and did not seek medical treatment. She came to the hospital this time because the neck mass recently increased rapidly and she felt pressure on the trachea, affecting swallowing. Ultrasonography showed that the maximum diameter of the hypoechoic nodules was 61*46mm in the left and no lymph nodes enlargement were seen on both sides.The patient had a partial left thyroidectomy and histopathological results revealed ICT. Therefore, she completed total thyroidectomy and cervical lymph node dissection. The postoperative process was relatively smooth and the patient was successfully discharged.

maximum diameter of the hypoechoic nodules was 61*46mm in the left and no lymph nodes enlargement were seen on both sides.The patient had a partial left thyroidectomy and histopathological results revealed ICT. Therefore, she completed total thyroidectomy and cervical lymph node dissection. The postoperative process was relatively smooth and the patient was successfully discharged.

Conclusion
Not all patients with insular thyroid carcinoma have similar imaging ndings, so Fine Needle Aspiration Cytology(FNAC)pathological diagnosis is necessary before surgery. Background Insular thyroid carcinoma is a rare thyroid malignant tumor rst described by Carcangiu [1] in 1984. It is an independent type of thyroid cancer and its biological behavior is between well-differentiated and anaplastic thyroid cancer. The condition is commonly seen in women between 46-52 years old and more than 50% of them are over 50 years old, younger patients are less commonly affected [2] . It is generally believed that insular thyroid carcinoma originates from thyroid follicular cells, but Lam [3] suggests that that well-differentiated cancer may gradually progress to insular thyroid carcinoma. Imaging manifested as progressive growth, irregular substantial mass, radionuclide scans often shows cold nodules, CT and B-ultrasound examination reveals calci ed nodules [4] . Ultrasound guided ne needle aspiration cytology (FNAC) is one of the important methods to obtain pathological diagnosis.The most common early clinical sign is a neck mass, as the mass enlarge, di culty in swallowing and breathing may occur but it generally does not cause hoarseness and most patients have normal thyroid function. Total thyroidectomy and neck dissection for lymph node metastases is the main treatment, and 131 I can be used after surgery.
Insular thyroid carcinoma patients mainly die of distant metastasis and the overall survival rate is better than anaplastic cancer [5] .At present, there are few reports about this diseases. Here we report a rare case of insular thyroid carcinoma on young woman and hope to help improve the clinical diagnosis and treatment of the disease in the future. The diagnosis of this disease meets the diagnostic criteria of Turin [6] .

Case Report
A 23-year-old young mother unintentionally found a left neck mass six months ago. Before admission, the patient felt that the neck mass rapidly increased and there was slight pain in local compression, but no hoarseness or sore throat. The patient's physical condition is normal, without any relevant medical history, no history of exposure to radioactive substances, and no bad habits such as smoking or drinking.
Ultrasound showed low echo nodes in the left thyroid, with a maximum diameter of 61*46 mm and no enlarged lymph nodes were seen on both sides (Fig. 1).
A further examination of enhanced CT was followed, a large and slightly low-density mass of the left thyroid was seen. The mass reached down to the chest cavity, pressing forward the anterior cervical muscles which invaded the thyroid isthmus and the right lobe, moreover, the tracheoesophageal groove and the trachea were also included. The lump was compressed and moved to the right. The enhanced scan was continued, then uneven and high enhanced areas were visible, but the boundary of the mass was still clear and no obvious enlarged lymph nodes were seen around it (Fig. 2).
Because of the results of tissue immunohistochemistry TTF1+, PAX8+, CEA -, Calcitonin-, medullary thyroid carcinoma and metastatic carcinoma could be excluded and poorly differentiated Insular thyroid carcinoma was diagnosed basing on the Turin criteria. Considering that the patient was young and the case was rare, our institution invited the Cleveland clinicin ,in the United States, to have a remote pathology consultation to further con rm the diagnosis. Subsequently, Total thyroidectomy and neck dissection for lymph node was performed (Fig. 4). The pathological results of the remaining tissues showed no tumor invasion and no lymph node metastasis. The patient was discharged from the hospital and referred to the oncology department for further treatment.Re-examination of cervical CT at 8 months after operation showed no obvious recurrence and metastasis.

Discussion
In 1983 Sakamoto [7] proposed that insular thyroid carcinoma was a subtype of poorly differentiated thyroid cancer. The biological behavior of its cancer cells is more aggressive than follicular thyroid cancer and papillary thyroid cancer, early involvement of adjacent lymph nodes may occur and the tumor recurrence rate is high [8] . Total thyroidectomy and cervical lymph node dissection is the rst choice for treatment. Isotope 131 I therapy may help to control tumor recurrence but is not routine treatment for PDTC [9] . Before the operation, the patient's ultrasound and neck enhanced CT showed a clear mass on the left border of the thyroid gland and no surrounding enlarged lymph nodes and calci cations. There is a slight difference from previous reports of related diseases. There was a de ciency during the treatment process, because the patient was not diagnosed before the operation, which led to the second operation. At the same time, we are reminded not to completely rely on imaging examination and ignore pathological examination. After all, ne needle aspiration cytology (FNAC) has been widely used to diagnose thyroid lesions [10][11] .
Insular thyroid carcinoma is a rare malignant thyroid tumor with a poor prognosis. Although this is not the rst reported case of this disease, it is hoped that this case will increase the number of young patients suffering from insular thyroid carcinoma, and provide an empirical reference for clinical diagnosis and treatment of that.