PMC6637673_01
Small monomorphic epithelial cohesive cells and focal follicular arrangements with monomorphic, coarse structured nuclei and a small rim of cytoplasm.
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fig1
Fine Needle Aspiration (FNA) revealed a monomorphic, partial follicular cell population (Figure 1) with focal weak immunohistochemical positivity for PTH.
Axial T1-weighted MR image (1) and postcontrast image (2) show a large mass near the right trachea without infiltration.
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Computer-assisted tomography (CT) as well as a MRI of the neck revealed a 5 cm large tumor at the right caudal pole of the thyroid with compression of the dorsolateral trachea without obvious infiltration, not distinguishable between thyroid and parathyroid, and tracheal stenosis was about 50% (Figure 2).
Cut surface of the specimen with a large indistinct colorful tumor with fibrous bands, hemorrhage, and infiltration of the thyroid. Focal perceived brown thyroid on the edge.
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fig3
The cut surface showed a multinodal, partially not clear demarcated protruding greyish-brown firm tumor with hemorrhagic areas, infiltrating the thyroid gland (Figure 3).
Tongue-like tumor infiltration of the thyroid.
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fig4
Microscopic examination showed a parathyroid tumor with multiple fibrous bands dividing the neoplasm into lobules with cellular areas arranged in sheets and trabeculae (Figure 4).
Pleomorphic cells with focal atypia without mitosis.
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fig5
Nuclear pleomorphism was partially present (Figure 5) but no mitotic activity.
Immunohistochemistry: Cytoplasmic positivity for PTH.
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Immunohistochemically, the tumor showed an expression of PTH (Figure 6) and Galectin-3 and a weak expression of CDKN1B (p27) which is often found in PC.
Focal perineural invasion and confirmation of malignancy.
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fig7
The tumor showed an invasion into the thyroid gland with tongue-like formations and after careful examination, an infiltration of perineural spaces (Figure 7) was found which confirmed the diagnosis of a PC.