Papillary Thyroid Carcinoma: Unusual Presentations and Metastasis

Introduction: Thyroid cancer 5th most common cause of cancer. Predominant in females with incidence of 3:1. median age 50 yrs. 5 years survival rate of 95%. PTC infrequently cause distant metastasis with bone metastasis in 4% of patients.[1] Case Details: First case: 31/M Presented with U/L limb weakness gradually progressing to quadriparesis. Evaluation reveals spinal lesions at C5. Underwent C5 corpectomy with C4-C6 Cervical laminectomy. The HPE of C5-C6 lesions reveals metastatic follicular variant of PTC. Retrospective evaluation reveals thyrotoxic profile (TSH<0.01mIU/L, TT4: 13.8 ug/dl) Hypoechoic thyroid nodule of size 12X10 mm. Underwent total thyroidectomy with status post RAI (200mCi). Patient started on LT4 therapy with follow up shows complete biochemical response and Whole-body iodine scan reveals no uptake in the body. Second case: 65-year-old male with right sided thyroid swelling (adenomatoid goiter on FNAC) for 25 years presented with features of thyrotoxicosis. Technetium uptake scan suggested toxic MNG with no uptake in the dominate nodule. Xray neck suggested tracheal shift to the left and patient was therefore advised right sided hemithyroidectomy after achieving euthyroidism with anti-thyroid drugs. Biopsy of the lesion suggested papillary carcinoma of thyroid – classic variant. Patient underwent completion thyroidectomy. Despite withholding levothyroxine supplementation, patient had only marginal elevation of TSH (9.2) and hence RAI therapy was not advised. Patient was lost to follow-up and presented after 4 years with loss of appetite and weight loss (~8 kg) for 6 months. He had suppressed TSH with elevated thyroglobulin levels with normal finding in the ultrasonography of neck. Chest x-ray showed multiple nodular opacities in B/L lower lung fields. Radioiodine uptake scan showed uptake in lung fields and thyroid bed. Patient received RAI (150 mCi). After 5 months of RAI, serum Thyroglobulin levels found to be still high (>484 ng/ml) and was planned for another dose of RAI. Discussion: Toraiah EA et al., suggested the most common site of metastasis for PTC is Lungs (53.4%) followed by bone (28.1%).[2] There is one Indian study by Karkuzhali P et al., from Madras who described 377 papillary thyroid carcinoma patients for various factors. They found that lymph node and metastasis elsewhere in 19.1 % of patients. They suggested that PTC in males is more multicentric than unicentric and the frequency of PTC is very less in males compared to females.[3] Conclusion: Thyroid malignancies with distant metastases may present with thyrotoxicosis. Functional metastases should also be suspected in cases of minimal TSH elevation post thyroidectomy. All the cold nodules in the background of hyperthyroidism should be evaluated for malignancy. Timely follow up is mandatory for Ca THYROID patients for early detection of distant metastases.