PMC6230986_01
Histology and Immunoprofile of Intrathyroidal Parathyroid Carcinoma. (a) The tumor is infiltrative within the thyroid. (b) There is vascular invasion characterized by intravascular tumor cells admixed with thrombus. (c) The tumor cells exhibit cytoplasmic reactivity for parathyroid hormone and (d) nuclear staining for GATA-3, confirming parathyroid differentiation. (e) Cytoplasmic reactivity for Galectin-3 is a feature suggesting parathyroid carcinoma. (f) The Ki67 labeling index is approximately 20%. (g) The tumor cells show loss of nuclear parafibromin reactivity and (h) there is diffuse staining for PGP 9.5.
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F1
Review of the pathology in the thyroidectomy specimen revealed that the index thyroid mass was indeed an infiltrative intrathyroidal neuroendocrine tumor (Figure 1a) that measured 2.7 cm and had multiple foci of vascular invasion characterized by intravascular tumor cells admixed with thrombus (Figure 1b). The Ki67 labeling index was 19.6% in an automated count of 1158 cells (Leica Biosystems; Figure 1f), there was reduced expression of BCL-2 and focal upregulation of cyclin D1 and p53. There was no loss of RB but marked reduction of p27. There was loss of nuclear parafibromin reactivity (Figure 1g) and PGP 9.5 was positive (Figure 1h).
Computed Tomography Imaging of Metastatic Parathyroid Carcinoma. (a) Multiple scattered lesions throughout both lung fields are consistent with metastatic parathyroid carcinoma. (b) Repeat imaging 3 months following treatment with the tyrosine kinase inhibitor sorafenib demonstrates reduction in the size of several of the pulmonary nodules which are now less prominent.
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F2
CT imaging identified no visible disease in the neck but multiple pulmonary nodules consistent with metastatic disease were noted (Figure 2a). Three months later, CT imaging showed early regression of the lung nodules (Figure 2b).