A Rare Case of Metastasis to the Mandible from the Thyroid Gland: a Case Report and Literature Review

Excerpt

A 56-year-old female with multiple comorbidities presented with a swelling in the lower jaw (Figs. 1 and 2). On examination, it was a hard 6 × 5 cm swelling in the right mandible, 3 cm from the symphyses and posteriorly involving the angle of the mandible. The oral cavity did not show any evidence of disease. Also, a 3 × 2 cm nodule in the right lobe and 1 × 1 cm nodule in the left lobe of the thyroid were palpated without cervical lymphadenopathy. Laryngoscopy revealed both the cords to be mobile. Fine-needle aspiration cytology revealed a Bethedsa 1, i.e., few follicular cells. A trucut biopsy was undertaken from the mandibular swelling, which revealed a metastatic lesion from the thyroid which was positive for thyroglobulin and CKT. A bone scan of Tc-99 was done as part of the metastatic evaluation and showed an increased uptake in the right body of the mandible. Contrast-enhanced CT neck showed a 2.8 × 2.9 × 1.6 calcific nodule in the right lobe of the thyroid, a 1.2 × 1 cm hypointense nodule in the left lobe of the thyroid, and a 4 × 3 cm contrast-enhanced osteolytic lesion in the right body of the mandible Fig. 3. The patient was counseled regarding the need for surgery and consent was obtained for the same. A total thyroidectomy with hemimandibulectomy and adjacent level 1 B node clearance was done Figs. 4 and 5. Postoperative period was uneventful and she was discharged on postoperative day 4. Histopathological examination proved it as a pT3NoM1 follicular variant of papillary carcinoma of the thyroid, hence staged as IVB. American Thyroid Association (ATA) risk of recurrence is High Risk to which she received 100 mCi. Her follow-up thyroglobulin, antithyroglobulin, and low-dose scan were within normal limits. Hence, she can be categorized as Excellent response as per the Dynamic Risk Stratification. She is to be maintained on a suppressive dose of thyroxine (latest value of TSH—1.1 ng/dl). She is on regular follow-up, and 1 year since the surgery, there are no signs of recurrence.

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