Neoplastic mimics or "pseudotumors" can simulate neoplasms on all levels of analysis- clinical, radiologic, and pathologic--and thus represent particular diagnostic pitfalls for the pathologist that can ultimately lead to therapeutic misdirection.

I. Kidneys and Ureter; Renal Angiomyolipoma; Juxtaglomerular Cell Tumor; Renomedullary Interstitial Cell Tumor; Cystic Nephroma; Xanthogranulomatous Pyelonephritis; Renal Malakoplakia; Other Inflammatory Pseudotumors; Renal Pelvis and Ureter; II. The Urinary Bladder; Von Brunn's Nests; Cystitis Glandularis (Including Mucinous Metaplasia); Nephrogenic Adenoma (Nephrogenic Metaplasia, Adenomatous Metaplasia); Papillary-Polypoid Cystitis; Fallopian Tube Prolapse; Giant Cell Cystitis; Radiation Cystitis; Malakoplakia; Fibroepithelial Polyps; Hamartomas; Endocervicosis and M¿llerianosis; Postoperative Spindle Cell Nodule; Inflammatory Pseudotumor; Paraganglia in the Bladder; III. The Prostate Gland; Atrophy; Adenosis; Sclerosing Adenosis ; Hyperplasia of Mesonephric Remnants; Nephrogenic Adenoma of the Urethra Involving Prostate; Cribriform Hyperplasia; Prostatitis; Malakoplakia; Xanthoma of the Prostate; Seminal Vesicle Tissue, Cowper's Glands, and Paraganglia in Prostate Specimens; Benign Glands around Nerves and in Skeletal Muscle; Radiation Effect; Squamous and Transitional Cell Metaplasia; Basaloid Lesions; IV. Testis, Scrotum, Penis; Cysts of the Tunica Albuginea; Infectious Orchitis; Nonimmune Granulomatous Orchitis; Autoimmune Granulomatous Orchitis; Tumefactive Malakoplakia (Greek: "Soft plaque"); Testicular Cysts; Adenomatous Hyperplasia of the Rete Testis; "Tumors" of the Adrenogenital Syndrome; Tumefactive Testicular Infarction, Torsion, and Hematoma Formation; Stromal Cell Hyperplasia in Androgen Insensitivity (Testicular Feminization); Syndrome Stromal Cell Hyperplasia in Cryptorchidism; Epididymis; Metaplastic Epididymitis; Cholesteatoma; Malakoplakia; "Proliferative" Spermatocele; Age-Associated Atypia of Epididymal Epithelium; Spermatic Cord; Ectopic Adrenal Tissue (Marchand's Rests; Adrenal Choristomas) in the Spermatic Cord; Lipogranulomas and Fibrous Pseudotumors; M¿llerian and Wolffian Embryonic Remnants; Proliferative Vasitis Nodosa; Endometriosis of the Spermatic Cord ; Seminal Vesicles and Ejaculatory Ducts; Age-Associated Epithelial Atypia; Ganglia; Scrotum; Meconium Periorchitis; Sclerosing Lipogranuloma; Fibrous Pseudotumor of the Scrotum; Florid Reactive Mesothelial Hyperplasia; Cutaneous Angiokeratoma; Fibrous Hamartoma of Infancy; Penile Skin; Malakoplakia; Plasmocytic (Zoon's) Balanitis; Pseudolymphomatous Lymphoid Infiltrates