case_images: PMC9898871_01
case_images: Gross and microscopic findings from total thyroidectomy specimen. (A) Gross examination of massive thyromegaly. (B) Thyroid with nodular hyperplasia (200x). (C) C-cell proliferation (CCH) in the intrafollicular space (200x). (D) High power field of CCH demonstrate small, round nuclei, and fine chromatin with clear or granular cytoplasm. Nuclear size is similar to or slightly larger than follicular cells. No mitotic figure, cytologic atypia or desmoplastic change is identified (400x).
case_images: cureus-0015-00000033384-i01.jpg
case_images: PMC9898871_01_cureus-0015-00000033384-i01.jpg
case_images: FIG1
case_images: Isthmus was 6 cm in size (Figure 1A). No significant cytologic atypia, mitotic figure, or desmoplastic change was identified (Figures 1A-1D, 2A-2C).
case_images: H&E examination and immunohistochemical staining. CCH identified on H&E slide (A) was stained strongly and diffusely positive for calcitonin (B). Collagen type IV immunostain showed intact basement membrane layer (C). (200x for A-C).
case_images: cureus-0015-00000033384-i02.jpg
case_images: PMC9898871_01_cureus-0015-00000033384-i02.jpg
case_images: FIG2
case_images: No significant cytologic atypia, mitotic figure, or desmoplastic change was identified (Figures 1A-1D, 2A-2C). Immunostain for collagen type IV highlighted the intact basement membrane layer (Figures 2A-2C).