PMC8016592_01
Neoplasia with microfollicular pattern of growth. The follicles are lined by cuboidal cells, lacking nuclear crowding and overlapping. The arrows mark rare epithelial tufts growing within the follicles, with a fibrovascular core, mimicking the appearance of renal glomerulus (a, b) and foci of capsular microinvasion (c, d, e) with stromal mucinous material (arrows) staining positively with Alcian Blue staining (f). H-E staining: (a) =200x, (b) =400x, (c) =100x, (d) =200x, (e) =200x, and (f) = Alcian Blue staining, 200x.
CRIPA2021-1686025.001.jpg
PMC8016592_01_CRIPA2021-1686025.001.jpg
fig1
The presence of epithelial tufts growing within the follicles, sometimes with a fibrovascular core, thus mimicking the appearance of renal glomerulus, was occasionally detected (Figures 1(a) and 1(b)). Interestingly, mucinous stromal material was evidenced at the periphery of the lesion, in foci of microinvasion (Figures 1(c)-(e)) and at the interface between the tumor and the surrounding parenchyma, where the capsule was absent (Figures 2(a) and 2(b)). Mucinous stromal material stained positively with Alcian Blue staining (Figures 1(f) and 2(c)). It was absent where the capsule was intact (Figure 2(d)) and in the central areas of the lesion (Figure 1).
Stromal mucinous material (a, b) positive for Alcian Blue staining (c) at the interface between the tumor and the surrounding parenchyma, in areas in which the capsule was absent (arrows). Stromal mucinous material was absent where the capsule was intact (d). (a, b) H-E staining, 200x. (c, d) Alcian blue staining, 200x.
CRIPA2021-1686025.002.jpg
PMC8016592_01_CRIPA2021-1686025.002.jpg
fig2
Interestingly, mucinous stromal material was evidenced at the periphery of the lesion, in foci of microinvasion (Figures 1(c)-(e)) and at the interface between the tumor and the surrounding parenchyma, where the capsule was absent (Figures 2(a) and 2(b)). It was absent where the capsule was intact (Figure 2(d)) and in the central areas of the lesion (Figure 1).