Abstract: FRI 299
Extranodular Microcalcifications and Psammoma Bodies
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Sonographic microcalcifications in a thyroid nodule are highly suggestive of malignancy and typically warrant follow-up with biopsy. It has been proposed that microcalcifications on thyroid ultrasound correlate to clusters of Psammoma Bodies (PB) pathologically, and are found in approximately 50% of all cases of Papillary Thyroid Carcinoma (PTC). PB may be formed by intracellular calcifications in the thyroid and by necrosis and calcification of intravascular or intralymphatic tumor thrombi. Extratumoral PB are thought to be associated with the spread of tumor cells via vascular or lymphatic channels and are associated with worse outcomes in patients with PTC. We present an interesting case of diffuse intranodular and extranodular microcalcifications on sonogram, with intratumoral and extratumoral PB and an aggressive tumor pathology.
A 31 year old female, initially referred for abnormal bone density, was found to have a small multinodular goiter. The patient was asymptomatic with no symptoms of hypothyroidism or hyperthyroidism. She denied history of head and neck radiation or family history of thyroid disease. Clinical examination was consistent with a small, multinodular goiter, with no palpable lymph nodes. Initial labs revealed TSH 4.80 mIU/L (n 0.4-4.0 mIU/L), Free T4 1.1 ng/dL (n 0.7-2.2 ng/dL) and Thyroid Peroxidase Antibody: 0.5 IU/ml (n 0- 5.5 IU/ml). Ultrasound revealed diffuse intranodular and extranodular microcalcifications, and the FNA was interpreted as PTC (Bethesda VI). Surgical pathology revealed multifocal tumor with marked fibrosis, infiltrative pattern of growth, lymph node metastases and diffuse intranodular and extranodular PB. Patient was treated with 125mCi of radioactive iodine and had an uneventful postoperative course.
Extratumoral PB may indicate aggressive behaviors such as tumor multifocality, extrathyroidal extension and lymph node metastasis. This case suggests that the detection of preoperative ultrasonographic extranodular microcalcifications maybe a useful indicator of the presence of extranodular PB and aggressive PTC. Future studies are required to describe the role of extranodular PB as a prognostic indicator of extratumoral spread of tumor. Further, if sonographic diffuse extranodular microcalcifications correlate with extranodular PB, this may prove to be a useful decision making criterion when determining preoperative or intraoperative management of PTC.