Introduction: Occult carcinoma of the thyroid is defined as a microcancer less than 1 cm in size, clinically undetectable. Discovered accidentally during routine radiological examination, cervical surgery of a benign thyroid tumor, varies from 0.01% to 35.6%. Mostly it is papillary type. Occult cancers revealed by bone metastasis have rarely been reported. We report two patient observations presenting bone localizations of occult thyroid carcinoma.
Observation 1: A 72-year-old woman with a history of right lobustomyectomy for a benign thyroid nodule 15 years ago had three thoracic parietal masses on the right and one on the left. A thoracic CT revealed solid and lytic cost masses: a posterior left centered on the 8th dimension of 70×81 mm and two on the right centered on the 10th posterior dimensions of 84×49 and 67×46 mm. A CT biopsy performed concluded a metastasis of vesicular carcinoma of the thyroid. Thyroglobulin+ and TTF1+. A cervical ultrasound showed two micro nodules of 6x 8 mm and 9×6 mm. She was summed left lobar thyroid with histopathological examination an aspect of a remodeled goitre without histological sign of malignancy. On the post-I131therapeutic whole-body scan, metastases intensively fixed radioactive iodine. A blood test of thyroglobulin, showing high levels at 500 ng/ml.
Observation 2: A 15-year-old patient consulted in neurosurgery for non-painful cranial parietal swelling of fortuitous discovery. A cerebral MRI performed revealed an aggressive solido-cystic osteolytic process of the right parietal vault with endocranial development. The patient underwent complete excision and cranioplasty. Pathological examination concluded bone metastasis of vesicular thyroid carcinoma thyroglobulin+ and TTF1+. The cervical ultrasound found two micro nodules TIRADS4b. Histological examination of the total thyroidectomy specimen found favor for a papillary micro carcinoma p T1m N0 M1. Thyroglobuline=38 ng/ml.
Discussion - Conclusion: The term occult thyroid carcinoma, as used by Woolner or thyroid micro-cancer, refers to a cancer whose diameter is one to a few millimeters. In the majority of cases, these micro-carcinomas are imperceptible and histological discovery per or post-operative, their incidence is variable. On the other hand, the micro carcinomas revealed by a bone metastasis, relatively more rare, must be considered as true cancers which have already given metastases and must be treated as such. Boucek et al divided it into four groups distinguished by their initial clinical presentation and the mode of discovery of the primary tumor. Our various reported cases highlight this entity with its diagnostic and clinical features.
18 - 21 May 2019
European Society of Endocrinology