PMC10400295_01
Endoscopic image of thickened, ulcerated mucosa involving 75% of the rectal circumference in case 1 (arrow).
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fig1
There was a continuous area of nonbleeding ulcerated, thickened mucosa involving three quarters of the rectal circumference, 12 cm proximal to the anal verge (Figure 1) on flexible sigmoidoscopy.
Fragment of ulcerated and necrotic rectal mucosa (arrow) adjacent to a fragment of rectal mucosa with prolapse and reactive epithelial changes in case 1 (double arrow; H&E 10x).
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The rectal mucosa present had reactive epithelial changes in a background of mucosal prolapse (Figure 2).
Endothelial cell nuclei of a vessel within granulation tissue with multinucleation, margination of chromatin, and molding in case 1 (arrows; H&E 60x).
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fig3
The endothelial cell nuclei lining rare vessels within the granulation tissue had a ground glass appearance with chromatin margination and molding (Figures 3 and 4), and similar viral inclusions were also seen in fibroblast nuclei adjacent to the vessels (Figure 5).
CD31 immunohistochemical stain highlighting endothelial cells of a granulation tissue vessel with enlarged endothelial nuclei containing viral inclusions in case 1 (arrows; 60x).
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fig4
The endothelial cell nuclei lining rare vessels within the granulation tissue had a ground glass appearance with chromatin margination and molding (Figures 3 and 4), and similar viral inclusions were also seen in fibroblast nuclei adjacent to the vessels (Figure 5).
Cluster of fibroblasts within granulation tissue with viral cytopathic effect including nuclear margination of chromatin in case 1 (arrows; H&E 60x).
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fig5
The endothelial cell nuclei lining rare vessels within the granulation tissue had a ground glass appearance with chromatin margination and molding (Figures 3 and 4), and similar viral inclusions were also seen in fibroblast nuclei adjacent to the vessels (Figure 5).
Herpes Simplex Virus immunohistochemical stain highlighting viral inclusions within granulation tissue fibroblast nuclei and within endothelial cell nuclei lining a vessel (red circle) in case 1 (40x).
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HSV immunohistochemical stain (IHC) highlighted viral inclusions within endothelial cell and fibroblast nuclei (Figure 6).
PMC10400295_02
Contrast-enhanced CT in case 2 shows marked eccentric thickening of the rectal wall (open arrows) with adjacent superior rectal (not shown), external iliac (not shown), and bilateral inguinal lymphadenopathy (solid arrows). The degree of eccentric wall thickening made malignancy high on the differential diagnosis.
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fig7
A pelvic CT-scan showed a long segment of marked rectal wall thickening with an adjacent 4.7 cm thick-walled perirectal air-fluid collection and prominent pelvic lymphadenopathy (Figure 7).
Endothelial cell nuclei of a vessel within granulation tissue with multinucleation, margination of chromatin, and molding in a background of a mixed inflammatory infiltrate composed of lymphocytes, plasma cells, neutrophils, and abundant eosinophils in case 2 (arrows; H&E 60x).
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fig8
Endothelial cell nuclei within rare granulation tissue vessels had viral-cytopathic effect including chromatin margination and molding (Figure 8).