Surgical Pathology Criteria–

Inverted Urothelial (Transitional Cell) Carcinoma

Differential Diagnosis

Nested Variant Urothelial Carcinoma Transitional/Urothelial Carcinoma with Inverted Pattern
Invasive carcinoma that looks deceptively non-invasive due to predominantly nested pattern Non-invasive inverted pattern of carcinoma that looks deceptively invasive
Overall invasive pattern, not circumscribed Lacks clearly invasive pattern
May involve muscularis propria Does not involve muscularis propria
Varying sizes and shapes of nests Frequently formed by fusion of trabeculae and cords (inverted papilloma like pattern)
Desmoplastic stroma may be present No desmoplasia

Urothelial Carcinoma with Inverted Growth Pattern Inverted Papilloma
Usually has a surface papillary component Surface everted papillary component absent or minimal
Cytologic features and disorder of carcinoma, appropriate to grade Bland, uniform, orderly cells
Mitotic figures present, appropriate to grade No mitotic figures
These may represent a spectrum, with an intermediate PUNLUMP with inverted pattern

Urothelial Carcinoma with Inverted Growth Pattern Florid von Brunn Nests, Cystitis Cystica/Glandularis
Usually has a surface papillary component Surface normal
Cytologic features and disorder of carcinoma, appropriate to grade Bland, uniform, orderly cells
Mitotic figures present, appropriate to grade No mitotic figures

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