Gra Menendez, Silvia1; Amdemichael, Eden2; Ikpeazu, Chukwuemeka3; Lew, John I.4; Casula, Sabina5
1 Assistant professor of Clinical Medicine, Division of Endocrinology and Metabolism, Department of Medicine, University of Miami
2 Endocrine Surgery Fellow, University of Miami
3 Associate Professor of Clinical Medicine, Hematology/Oncology
4 Associate Professor of Surgery. Chief, Division of Endocrine Surgery. DeWitt Daughtry Family Department of Surgery
5 Assistant professor of Clinical Medicine, Division of Endocrinology and Metabolism, Department of Medicine, University of Miami
Background: Poorly differentiated thyroid carcinoma is a rare form of thyroid carcinomas and furthermore, poorly differentiated thyroid carcinoma arising in thyroglossal duct cyst. They display an intermediate behavior between well-differentiated and anaplastic thyroid carcinomas. They have a propensity to metastasize to regional lymph nodes and distantly, most commonly to the lung and bones. Adrenal metastases are uncommon.
Patient Findings: A 69-year old woman was referred to Endocrinology for evaluation of a left adrenal incidentaloma. CT abdomen showed a 3.5 cm adrenal mass with 38 Hounsfield units. Patient had medical history of poorly differentiated thyroid carcinoma of the thyroglossal duct cyst. She underwent total thyroidectomy and RAI therapy on 2015. Posttreatment and diagnostic whole body scan did not showed abnormal uptake. PET/CT from July 2016 showed an intensely metabolic area in the left adrenal gland. Her suppressed thyroglobulin was 566. Patient underwent left adrenalectomy and pathology showed metastatic poorly differentiated thyroid carcinoma. Postsurgical suppressed thyroglobulin was 1.5 ng/mL.
Summary & Conclusions: We report an extremely rare case, and unique in the literature, of a poorly differentiated thyroid carcinoma arising in the thyroglossal duct cyst. What also makes this case particularly rare and unique is the fact that she presented with an isolated left adrenal metastasis. Her thyroglobulin decreased considerably after the left adrenalectomy. Thyroglobulin panel is a good and reliable marker for persistence or recurrence of the thyroid cancer in this patient.