SUN-LB101 Papillary Thyroid Cancer Metastasis with a Normal Thyroid Gland Coexisting Malign Melanoma: A Case Report of a Rare Phenomenon

INTRODUCTION: Thyroid carcinoma without primary tumor with lymph node metastasis is a rare clinic manifestation. We report a thyroidectomyized patient with benign pathology who has diagnozed as lymph node metastatic papillary thyroid cancer while the prosedure of malign melanoma operation. CASE: A 67 year old woman was referred to our hospital for evaluation of a left pre auricular and left cervical mass. She underwent a total thyroidectomy operation at the other clinic which she had been followed up with multinodular thyroid for approximately for 4 months and resulting non malignant on pathology report. She did not have any risk factor for thyroid cancer. The thyroid function tests were within normal range while thyroid autoantibodies were negative. An ultrasound examination was performed and confirmed a 20x13x30 mm solid mass on the left side of the sterno gleno mastoid muscle. Fine-needle aspiration biopsy of lesions was performed. At pathological examination, left parotid gland biopsy resulted as malign melanoma. Positron emission tomography showed a 13x13 mm sized lesion in the left parotid gland and a hypermetabolic lymph node (SUV MAX 4.17) on the left cervical region II. The patient underwent a left total paratidectomy and left modified lymph node dissection. Pathological examination revealed multiple metastatic lymph nodes of malign melanoma around parotid gland and also metastatic lymph nodes of papillary thyroid carcinoma around the juguler vein which measured 0.8 cm. After this situation the total thyridectomy specimen reevaluated and revealed non-malign thyroid tissue. The patient received adjuvant radiotherapy after the surgery. The Medical Oncology department planned Interferon therapy during follow up. Also ablative therapy with iodine is planned. DISCUSSION: In some rare cases, papillary microcarsinoma may not been diagnosed even after performing total thyroidectomy. This situation may be related to whether the thyroid was entirely sampled and the sample may not be from the malignant area if the malign tissue is too small. On the other hand there has been reported some cases with histologically confirmed metastatic thyroid carsinoma in lymph nodes with absence of a primary thyroid tumor after the histopathologic examination of the entire gland. We wanted to point out even thyroidectomy pathology is benign, papillary thyroid cancer can be diagnosed with metastatic lymph node afterwards. In this rare but real case, we report a patient with methastatic thyroid cancer without primary tumor coexisting with Malign melanoma that rarely be encountered in daily practice. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.