case_images: PMC7402866_01
case_images: MIBI-Technetium subtraction scintigraphy, with evidence of left inferior parathyroid tracer uptake.
case_images: OTT-13-7599-g0001.jpg
case_images: PMC7402866_01_OTT-13-7599-g0001.jpg
case_images: F0001
case_images: The patient followed up routinely until 2018, when neck ultrasonography for relapsing hyperparathyroidism revealed an adenoma in the left inferior parathyroid, confirmed by technetium (99mTc) Sestamibi scintigraphy (Figure 1).
case_images: Histopathology of resected medullary thyroid cancer (MTC). Microscopically, it revealed polygonal cells with pale cytoplasm surrounded by fibrosis, collagen and amyloid tissue. H&E staining, (A). On immunohistochemistry, MTC was positive for Chromogranin (B), and CEA (C), and slightly positive for calcitonin (D). Magnification 40x (A); 100x (B); 200x (C and D).
case_images: OTT-13-7599-g0002.jpg
case_images: PMC7402866_01_OTT-13-7599-g0002.jpg
case_images: F0002
case_images: On immunohistochemistry (Leica Bond system; Bond-III; Leica Microsystems, Milan, Italy), the medullary tumor showed positive reactions to Chromogranin A and carcinoembryonic antigen (CEA) and was slightly reactive to Calcitonin; Ki67 expression was low (<5%) (Figure 2A-D).