PMC8483267_01
MRI of the patient's abdominal cavity (without contrast). (A) In the upper pole of the right kidney, the lesion of an irregular shape and inhomogeneous structure was connected with the pelvicalyceal system, coronal projection, SSFP mode. (B) The lesion had an irregular shape and a bumpy surface, 3D-reconstruction from the SSFP series. (C-E) The multinodular nature of the lesion and clear boundaries were determined in axial sections, T1 mode.
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F1
In computer tomography (CT) plain scan and magnetic resonance imaging (Figure 1), the formation had irregular contours.
Fragments of the kidney and cystic lesion. Gross evaluation (A,B) demonstrates cystic lesion with adjacent renal parenchyma (p) separated by septa with varying wall thickness. Adhesions tightly connected the lesion with the kidney capsule and adjacent adipose tissue. The lumen was filled with gray-brown cheesy keratinized masses (k). It was connected to the small renal calyx (c) with the isthmus (i). Mucosa of the calyx was gray, smooth, with single overlays of horny masses. (C) The histological study revealed keratinized mass in the lumen of the lesion. (D) The renal parenchyma was separated from the cyst wall with adipose tissue of the renal sinus. (E,F) Three types of epithelium lined the cyst wall: stratified squamous epithelium (sq) with a developed granular layer and hyperkeratosis, urothelium (ur) and simple cuboidal epithelium (cub). (G) We also detected the focuses of chronic inflammatory infiltration. (H) Atrophic renal parenchyma was adjacent to the epithelial lining in some areas.
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F2
Gross evaluation of the surgical material revealed a multichamber keratin-filled lesion in the upper pole of the right kidney, 7 x 6 x 5 cm in size (Figures 2A,B). In histological analysis (Figures 2C-H), the lining of the lesion consisted of alternating sections of urothelium and epidermis with developed granular and stratum corneum. In some areas, the wall of the lesion had well-defined contours and was separated from the renal parenchyma by renal sinus adipose tissue (Figure 2D and Figures 3A,D). Somewhere, it was completely absent, the epithelial lining closely adjoined to the renal parenchyma and a single-layer cuboidal epithelium lined the wall (Figures 2F,H, and Figures 3C,E,F,I,L).
Immunohistochemical study of kidney cystic lesion. The cyst wall areas contained numerous smooth muscle cells (A), singular cells (B) or completely lacked the cells (C). (D-F) The cuboidal epithelium, urothelium and epithelium of the kidney tubules were strongly positive for CK7, while the stratified squamous epithelium did not express the marker. (G-I) The urothelium was positive for uroplakin III, while the cuboidal epithelium expressed this marker weakly and irregularly. (J-L) The multilayer squamous epithelium and tubule epithelium were not stained with antibodies against uroplakin III, but expressed p63. The cuboidal cyst epithelium had weak and focal positive expression of p63, the epithelium of the tubules was not stained.
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F3
The wall consisted of fibrous tissue with focuses of adipose cells, multi-caliber blood vessels and clusters of smooth muscle cells, which were clearly visualized by immunohistochemistry (Figures 3A-C). Urothelium and cuboidal epithelium of the cyst expressed cytokeratin 7 (CK7) and uroplakin 3, while the stratified squamous epithelium did not express these markers (Figures 3D-I). Both urothelium and squamous epithelium expressed p63 (Figures 3J-L). In some areas, the wall of the lesion had well-defined contours and was separated from the renal parenchyma by renal sinus adipose tissue (Figure 2D and Figures 3A,D). We observed the areas with atrophy of the smooth muscle layer (Figure 3B). Somewhere, it was completely absent, the epithelial lining closely adjoined to the renal parenchyma and a single-layer cuboidal epithelium lined the wall (Figures 2F,H, and Figures 3C,E,F,I,L).