Endocrine Abstracts

Introduction: Distant metastases of thyroid tumors are rare. They are mainly of pulmonary (10-15%), bone (9%) and brain (<1%) location. These metastases are more frequent with vesicular (20%) than papillary (3.5%) histological type carcinoma. The aim of our work is to document the clinical and radiological aspects as well as the therapeutic modalities of these entities.

Materials and methods: We report 4 cases of distant metastasis that revealed a differentiated thyroid carcinoma: two cases of pulmonary localization and two cases of bone localization collected at our department of otorhinolaryngology and cervicofacial surgery.

Observations (pulmonary metastasis) : These are two women aged 38 and 45 years who consulted for respiratory symptomatology without palpable thyroid nodules, with the finding of a micronodular miliary on standard chest radiography. A whole-body 131 iodine scan and a chest CT scan were also performed for the second patient, confirming the metastatic nature of the lung involvement. The diagnosis was confirmed on lung biopsy for both patients. Total thyroidectomy with bilateral functional dissection was performed in both cases confirming the presence of multifocal papillary carcinoma. A complement by iratherapy allowed to sterilize the sites in one of the two patients after 6 years, and to decrease the pulmonary iodine fixation for the other patient after 6 months.

Observation (bone metastasis): This is a 55-year-old woman and a 60-year-old man who consulted for low back pain with motor deficit related to lumbosacral osteolysis and ductal invasion for the woman and neck pain for the man. The biopsy concluded to a metastasis of a vesicular carcinoma of the thyroid in both cases. Further imaging showed multinodular thyroid involvement without adenopathy in both cases. The female patient underwent decompressive radiotherapy. Both patients underwent total thyroidectomy associated with bilateral central curage. The histological examination had confirmed the vesicular type for the female patient and the papillary type for the male patient.

Conclusion: Visceral metastases of differentiated thyroid carcinoma have no clinical or radiological specificity. The metastatic potential remains independent of the size of the thyroid nodule. These metastases are more frequent with the vesicular histological type and have a more reserved prognosis. The presence of a single metastasis should prompt treatment with a carcinological aim.