PMC4142373_01
FNA initially reported sheets of follicular cells with oncocytic metaplasia, some naked nuclei, and focal inspissated colloid, compatible with Hurthle cell thyroid lesion. This was difficult to differentiate from parathyroid lesion if lacking of clinical information.
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Repeated FNA was done with the result of Hurthle cell lesion (Figure 1).
Ultrasonogram of thyroid gland and parathyroid glands. (a) Ultrasonogram and (b) color Doppler flow of right thyroid lobe showed a 2.8 x 1.9 cm heterogenous hypo-to-isoechoic with central hypervascularity solid mass located just inferior to right lobe of thyroid gland. The presence of extrathyroidal feeding artery or polar artery was shown (arrow). This mass was corresponding to palpable neck mass.
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On ultrasound examination, a 2.8 cm heterogenous hypervascular mass was located posterior to the right inferior pole of thyroid gland (Figure 2).
Pathology of parathyroid carcinoma. (a) Gross pathology of parathyroid carcinoma. A large solid tan mass (left, P) was adhered to the right lobe of thyroid gland (right, T). (b) Histopathology demonstrated vascular invasion (arrow) in the tumor capsule (H&E, 40x). (c) The tumor composed mixture of chief cells and oncocytic cells types arranged in solid sheets trabecular and nest pattern (H&E, 200x). (d) Immunohistochemical study for parathyroid hormone (PTH) revealed immunoreactivity in the tumor cells (PTH, 400x).
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Therefore, parathyroid carcinoma was suspected, and en bloc resection was performed (Figure 3(a)). The pathology result was parathyroid carcinoma which microscopically demonstrated vascular invasion in the tumor capsule (Figure 3(b)). The tumor composed mixture of chief cell and oncocytic cell types with occasional nuclear atypia and prominent nucleoli, arranged in solid sheets trabecular and nest pattern (Figure 3(c)). Immunohistochemical (IHC) study revealed positive immunoreactivity for chromogranin A and parathyroid hormone (Figure 3(d)) but negative immunoreactivity for synaptophysin, calcitonin, and thyroglobulin.
PMC4142373_02