Fig. 1
From: A nonfunctioning parathyroid carcinoma misdiagnosed as a follicular thyroid nodule
Cytological and histological specimens of nonfunctioning parathyroid carcinoma. a Cytological specimen showing epithelial cells organized in small cohesive clusters resembling thyroid microfollicles (Papanicolaou-stain, ×40 original magnification). b Histological section showing the neoplastic invasion of the neighboring thyroid tissue (arrows indicate the thyroid tissue; hematoxylin- and eosin-stain, ×2 original magnification). c Histological section showing the neoplastic invasion of the soft tissue surrounding the parathyroid tumor (*indicates the soft tissue; hematoxylin- and eosin-stain, ×2 original magnification). d–f Immunohistochemical stainings showing absence of immunoreactivity of the parathyroid tumor to thyroglobulin ((d), ×4 original magnification) and strong immunoreactivity to Chromogranin A ((e), ×4 original magnification) and parathyroid hormone (f), ×4 original magnification)