case_images: PMC7728115_01
case_images: Fine-needle aspiration cytology. First study: (A) Groups and microfollicles of clear balloon-shaped cells showing abundant fine vesicles in their cytoplasm. Second study: (B) A cluster and a microfollicle of clear balloon-shaped cells can be seen - nuclei are round with a visible nucleolus; (C) A microfollicle is displaying a central lumen - there is slight anisokaryosis. Papanicolaou (Pap) staining: (A-C) x400
case_images: RJME-61-1-219-fig1.jpg
case_images: PMC7728115_01_RJME-61-1-219-fig1.jpg
case_images: F1
case_images: There were groups of clear cells or microfollicular structures with a diffusely vacuolated cytoplasm (Figure 1A). Based on these findings the successive diagnoses in two samples were follicular neoplasia (Figure 1, B and C).
case_images: Total thyroidectomy. The right lower lobe contains a 2 cm diameter, solid, pale tan, nodular lesion
case_images: RJME-61-1-219-fig2.jpg
case_images: PMC7728115_01_RJME-61-1-219-fig2.jpg
case_images: F2
case_images: The right lower lobe contained a 2 cm diameter encapsulated, solid, pale tan, fleshy, nodular lesion (Figure 2).
case_images: Histopathology of the follicular adenoma with clear cell change: (A) Well-circumscribed lesion with a thin smooth capsule of fibrous connective tissue; (B) Trabeculae and solid nests of clear balloon-shaped cells containing fine vesicles - many nuclei are central, hyperchromatic and show a single nucleolus. Hematoxylin-Eosin (HE) staining: (A and B) x400
case_images: RJME-61-1-219-fig3.jpg
case_images: PMC7728115_01_RJME-61-1-219-fig3.jpg
case_images: F3
case_images: The nodular lesion of the right lobe was well circumscribed, with a thin smooth capsule of fibrous connective tissue (Figure 3A). The cells were grouped in solid areas showing a diffuse, trabecular, or nesting pattern of growth (Figure 3B) with occasional formation of microfollicular structures with central lumen surrounded by clear cells (Figure 4A).
case_images: Architecture of the follicular adenoma with clear cell-change: (A) Microfollicular architecture, structures with a central lumen are surrounded by clear cells - scant amount of colloid shows pale eosinophilic staining; (B) Central lumina are occupied by PAS-positive colloid - the PAS staining accentuates the cytoplasmic granularity produced by the confluence of fine cytoplasmic vesicles. Hematoxylin-Eosin (HE) staining: (A) x400. Periodic Acid-Schiff (PAS) staining: (B) x400
case_images: RJME-61-1-219-fig4.jpg
case_images: PMC7728115_01_RJME-61-1-219-fig4.jpg
case_images: F4
case_images: The cells were grouped in solid areas showing a diffuse, trabecular, or nesting pattern of growth (Figure 3B) with occasional formation of microfollicular structures with central lumen surrounded by clear cells (Figure 4A). The lumens contained PAS-positive colloid (Figure 4B). The PAS staining accentuated the cytoplasmic granularity (Figure 4B) and this reaction was diastase resistant indicating the absence of glycogen.
case_images: IHC reactivity of the follicular adenoma with clear cell change. The clear balloon-shaped cells show positivity for pan-CK AE1/AE3 (A, x200), TGB (B, x400), PAX8 (C, x400), and TTF-1 (D, x400). IHC: Immunohistochemical; Pan-CK: Pan-cytokeratin; TGB: Thyroglobulin; PAX8: Paired box gene 8 protein; TTF-1: Thyroid transcription factor-1
case_images: RJME-61-1-219-fig5.jpg
case_images: PMC7728115_01_RJME-61-1-219-fig5.jpg
case_images: F5
case_images: The IHC panel revealed the tumor cells positive for pan-cytokeratin (CK) AE1/AE3 (Figure 5A), thyroglobulin (TGB) (Figure 5B), paired box gene 8 protein (PAX8) (Figure 5C), and thyroid transcription factor-1 (TTF-1) (Figure 5D), whereas no immunoreactivity was seen for renal cell carcinoma marker (RCCM), cluster of differentiation 10 (CD10), carbonic anhydrase IX (CAIX), anti-mitochondrial antibody (AMA), PTH, p53 protein, anti-human melanosome [human melanoma black 45 (HMB45)], S100 protein, and smooth muscle actin (SMA).