Relationship Between rhTSH Administration and Thyroid Cancer Progression: A Case Report

Abstract

Introduction: The relationship between the administration of recombinant TSH (rhTSH) and the progression of thyroid cancer has been described in some case reports (1). There are scant data suggesting that rhTSH acts as a growth factor that stimulates metastatic tumor expansion. Case Report: A 55 year old male patient who 3 years ago reported an evident mass at cervical level. The ultrasound documented a large thyroid mass with an endothoracic component. The FNA reported BETHESDA IV, suspicious for follicular neoplasia. Extension studies showed lytic left parietal bone lesion and liver metastatic compromise. The pathology of the total thyroidectomy showed a follicular carcinoma with a micronodular pattern and capsular invasion, of 19x9x7 cm, vascular and esophageal involvement T4BN0M1. He was sent to radioiodine therapy with 100 MCI with previous suspension of LT4 (Preablative TGL> 300 ng / ml (<50 ng / ml) Abs-TGL 2 IU / ml (<2 IU / ml) TSH 31.3 mIU / L (0.37-4.7 mIU / L) and body scan documenting uptake of the radiotracer at the left parietal, the anterior costal grating, and liver. A second dose of iodine was applied, with 150 MCI after stimulation with thyrotropin (Preablative TGL> 300 ng / ml, Abs-TGL 1.76 IU / ml, TSH 83 mIU / L) Immediately after the administration of rhTSH, the patient described the appearance of alopecic plaques on the scalp, sensation of mass at the right upper quadrant of the abdomen and bone pain in the right rib cage and at the right hip, which progressively worsened the following days until they were incapacitating. The scan report showed a new uptake in dorsal vertebrae, the MRI showed new bone injury at the innominate bone, as well as increase in the sum of its maximum dimensions by 22%, indicative of progression. The cerebral angio-MRI showed hypervascularized metastasis at the left parietal level. Bone scintigraphy documented foci of hyper uptake in both parietals, manubrium and sternal body, 5-8 right anterior costal arches, right scapula, both humeral heads, vertebral bodies T3-T5-T7L4, right acetabulum, left proximal femur and the entire length of the right femur. The clinical and imaging worsening of the bone lesions after the application of rhTSH was striking, for this reason radiotherapy and embolization of the liver lesion was performed. The patient was not a candidate for neurosurgical management due to the vascular component of the cranial lesions. Conclusion: rhTSH is a very well-tolerated method that avoids symptoms associated with severe hypothyroidism. However, it has been associated with neoplastic progression. This is one of the few cases documented in the literature where there is a direct association between the administration of rhTSH and the progression of bone metastases. References: (1)Braga M. Ringel M. Cooper DS. Sudden Enlargement of Local Recurrent Thyroid Tumor after Recombinant Human TSH Administration. J Clin Endocrinol Metab. 2001; 86(11):5148–51.