Embryology and Anatomy of the Testis Embryology Development of the Testis Genetic Mechanisms Involved in Sex Determination and Testicular Differentiation Sexual differentiation is the result of complex genetic and endocrine mechanisms that are closely associated with the development of both…
Embryologic Development and Normal Anatomy The urethra serves as a conduit for urine from the urinary bladder to the exterior through the external urethral meatus. In males it also serves as a conduit for semen. The epithelium of the urethra…
Introduction The seminal vesicles were described by the Italian anatomist Berengario a Carpi in 1521. These paired androgen-dependent accessory sex glands were first regarded simply as storage sites for semen, but their milky alkaline secretions are now known to constitute…
Benign Epithelial Tumors and Tumor-like Proliferations Prostatic Cysts Giant multilocular prostatic cystadenoma is a large tumor composed of acini and cysts lined by prostatic-type epithelium set in a hypocellular fibrous stroma. This rare tumor arises in men between 28 and…
Embryology and Fetal-Prepubertal History The prostate is derived from the urogenital sinus. During the first 10 weeks of gestation, testosterone from the embryonic testes stimulates ingrowth of epithelial buds into urogenital sinus mesenchyme through a feedback loop. The mesenchyme induces…
Introduction Examination of urine is one of the oldest medical tests, used by Samarians, Babylonians, Egyptians, Indians, and Greeks in their traditional medicine. It was not until after Papanicolaou and Marshall published the first article in 1945 that urine cytology…
Carcinoma of the urinary bladder is the fourth most common malignancy in men, accounting for an estimated 60,490 new cases and 12,240 cancer deaths in the United States in 2018. Significant progress has been made in the diagnosis and treatment…
Embryology and Anatomy Embryology The common excretory ducts (the dilated segments of the mesonephric ducts distal to the ureteral buds) become absorbed into the urogenital sinus after the fourth week of gestation. Their epithelium merges toward the midline and forms…
Introduction Fine needle aspiration (FNA) of the kidney is a useful technique for diagnosing a specific subset of renal lesions. Most renal lesions in adults are either benign cysts (based on their radiographic appearance) that can be left alone or…
The renal pelvis and ureter are muscular conduits lined by urothelium that function to propel urine from the renal calyceal system to the urinary bladder. The ureter and renal pelvis are affected by developmental, reactive, and neoplastic disorders. The developmental…