Category: Thyroid

Monitor: 31

31 - PERSISTENT POSITIVE RADIOIODINE WHOLE-BODY SCAN IN A PATIENT WITH DIFFERENTIATED CANCER OF THYROID

Saturday, Apr 27
11:30 AM – 12:00 PM

Objective : To present the case of a patient with differentiated thyroid cancer (DTC) with whole-body scans (WBS) with radioiodine (RAI) false positives for a pulmonary aspergilloma.


Methods : The clinical and paraclinical characteristics of the patient are described.


Results : Male, 34 yo. Convulsive cough in childhood. No TBC. He underwent total thyroidectomy due to the presence of 1 nodule of 3.5 cm whose FNAB was reported as Bethesda IV and the pathology reported follicular adenoma and incidentally found 1 PTC, 100% follicular variety; 3mm diameter, partial encapsulated, without evidence of lymphatic embolism, which does not compromise the thyroid capsule in the RTL; and another PTC, 100% follicular variety, 5mm diameter with cicatricial fibrosis area and microcalcification with perineural lymphatic tumor microembolism that partially compromises the capsule. He received RAI (100mCi) with positive WBS in the neck and in the middle third of the left lung. Two years later, a new WBS with 5mCi of RAI reported positive in the left lung, reason why 6 months later his doctor indicated a 2° therapeutic dose with RAI (100mCi) whose WBS was reported as a focus of abnormal uptake in the left lung. For what was referred to our hospital. Analytical: Tg <0.2ng/ml and AbTg (-) without suppressive doses of LT4, we do not have previous levels of these hormones. CT of the thorax showed a hypodense lesion of irregular contours with cavitation at a level with poor uptake of a contrast substance located in the middle third of the left hemitorax with microbulbs, measuring 23mm in greater diameter, with a density that varies between 8 and 23 HU. The surgeon found the partially destructured left upper lobe characterized by cavitary bronchiectasis of mycotic content whose histological characteristic corresponds to pulmonary aspergilloma with bronchial dissemination. No evidence of cancer in lung tissue.


Discussion : Although it is true that there are DCT management guidelines, we see that our patient had the persistence of a "positive" WBS for years that warranted the administration of radioiodine despite the probable incongruence between the WBS and the initial risk stratification as the concentration of circulating thyroglobulin. Although WBS is a sensitive method for the detection of normal and abnormal thyroid tissue, especially when performed after the ablative dose, it should be taken into account that false positives may occur (uptake of RAI in the absence of residual thyroid tissue or metastasis). ) in different situations.


Conclusion : In patients with DCT, a response to treatment with undetectable thyroglobulin levels and positive functional imaging studies, the possibility of false positives should be considered.

Jose L. PAZ-IBARRA

ENDOCRINOLOGIST
HOSPITAL NACIONAL EDGARDO REBAGLIATI - UNIVERSIDAD NACIONAL MAYOR DE SAN MARCOS. LIMA - PERU
Lima, Lima, Peru

PERUVIAN ENDOCRINOLOGIST, UNIVERSITY TEACHER, ACTIVE MEMBER OF AACE, AREAS OF INTEREST NEUROENDOCRINOLOGY, THYROID, ENDOCRINOLOGY OF REPRODUCTION AND BONE MINERAL METABOLISM

Regina Benites

ENDOCRINOLOGY RESIDENT
HOSPITAL REBAGLIATI - LIMA - PERU

RESIDENT