• Extraperitoneal cavity: contiguous with retroperitoneal space
• Retropubic space of Retzius: contiguous with posterior pararenal space + extraperitoneal fat
• Perineum: below pelvic diaphragm
• Parametrium: contained within broad ligament
• Denonvillier’s fascia: positioned between prostate and rectum

• Combination of coritcal & medullary nephrocalcinosis suggests primary oxaluria

• Cortical Necrosis (Acute)
• Oxalosis
• Alport Syndrome
• Glomerulonephritis (Chronic)

• Medullary Sponge Kidney
• Alkali Excess
• RTA (Type 1, Distal), Renal Medullary/Cortical Necrosis
• Chronic Glomerulonephritis
• Hyperoxaluria, Hypercalcemia (Hyperparathyroidism), Hypercalciuria

• Pyelonephritis
• Obstruction
• Sickle Cell
• TB/Trauma
• Cirrhosis
• Analgesic Nephropathy
• Renal Vein Thrombosis
• Diabetes

• HIV
• Inflammation
  • Glomerulonephritis
  • HTN, DM
• Vascular
  • SLE / Vasculitis
• Multiple Myeloma
• Acute Tubular Necrosis / ARPCKD
• Nephrocalcinosis

• ESRD
• Hemolytic Uremic Syndrome

• Tumor
  • Leukemia / Lymphoma
  • Myeloma
• Inflammation (acute)
  • Glomerulonephritis
  • Interstitial Nephritis
  • ATN
• Metabolic
  • Amyloid
  • Diabetes
  • Gaucher's
  • Acromegaly
• Vascular
  • Bilateral renal vein thrombosis
• Polycystic Kidney Disease
• Collagen Vascular Disease

• Inflammation (chronic)
  • Pyelo, Glomerulonephritis, Interstitial Nephritis
• Reflux (chronic infection)
• Bilateral renal artery stenosis

• Vascular (RAS / RVT)
• Obstruction
• XRT
• Hypoplasia
• Subcapsular hematoma (chronic)

• iatrogenic
• post-infectious (gonococcal or non-gonococcal)
• non-infectious irritation (chemical or Reiter's)
• traumatic injury
• neoplasm (long, irregular stricture ± fistula)

• Category I - No atypical features
  • US - anechoic without internal echoes, with good thru transmission and a barely perceptible but well defined wall
  • CT - fluid density, no enhancement and imperceptible wall
• Category II - homogeneously hyperdense cyst that is not enhancing, or thin (<1mm) septations or thin wall Ca+
  • must be 3 cm or less in diameter, have one quarter of its wall extending outside the kidney so the wall can be assessed, and be nonenhancing after contrast material is administered
• Category IIF - minimally complicated cysts that need follow-up
  • not well defined by Bosniak but consists of lesions that do not neatly fall into category II
  • have some suspicious features that deserve follow-up up to detect any change in character.
• Category III - true indeterminate cystic masses that need surgical evaluation, although many prove to be benign
  • thicker septations or multiloculated, coarser Ca+ or solid component that is not enhancing
  • may show uniform wall thickening, nodularity, thick or irregular peripheral calcification, or a multilocular nature with multiple enhancing septa
  • hyperdense lesions that do not fulfill category II criteria are including in this group.
• Category IV - needs nephrectomy
  • nonuniform or enhancing thick wall, enhancing or large nodules in the wall, or clearly solid components in the cystic lesion
  • enhancement of at least 10 HU

• Stage 1 → confined by renal capsule (completely in kidney)
• Stage 2 → beyond capsule but confined within Gerota’s fascia
• Stage 3A → extension to renal vein or IVC
• Stage 3B → positive lymph nodes
• Stage 3C → both venous extension and adenopathy
• Stage 4A → grows through gerotas fascia into adjacent organs (other than adrenal)
• Stage 4B → distant mets

• cystitis cystica
• interstitial cystitis
• TB
• rads
• unused bladder
• surgery and schistosomiasis

• Collection - urinoma, hematoma, abscess
• IVC obstruction
• Lymphoma / adenopathy
• Lipomatosis
• Iliopsoas hypertrophy

• Fungus ball
• Ureteritis cystica → epithelial/ subepithelial cysts due to inflammation or irritation (metaplasia of Brunn’s nests)
• Clot
• Fibroepithelial polyp
• Endometriosis
• Stone / Sloughed papilla
• Tumor / TB

• Leukoplakia: associated with Schistosomiasis; premalignant → squamous cell carcinoma
• Malakoplakia: chronic gram (-) infection (E. coli #1); ↑ DM → foamy macrophages (Hansemann) with PAS (+) inclusions (Michaelis-Guttman bodies); raised yellow lesions
  • looks like ureteritis cystica

• viral and bacterial infection
• drugs - cyclophosphamide (cytoxan)
• eosinophilic
• cystitis cystica

• 1-3 mm outpouchings
• DDx → calculi / infections / CA (#1 = TCC)

• Risks: azo-dyes, cyclophosphamide, phenacetin
• Radiographic:
  • “Wine glass/goblet” deformity (dilated distal ureter)
  • Bergman sign (coiled retrograde catheter)

• Distribution:

• Medial
  • Retroperitoneal fibrosis: drugs (methylsergide, ergotamine); XRT; prior surgery; malignancy; connective tissue disorders
  • Retrocaval ureter (right only)
  • Pelvic lipomatosis: ↑ black males; “tear-drop” or “pear”-shaped bladder; associated with ureteritis cystica
  • Other: hematoma; iliac LAD or aneurysms; adnexal mass; surgery
• Lateral:
  • AAA
  • LAD; psoas hypertrophy
  • Central pelvic mass
  • Retroperitoneal fat (≠ pelvic lipomatosis)

• Infection: TB; Schistosomiasis; abscess; fistula
• CA: metastases; local extension; TCC; lymphoma
• XRT
• Inflammation: calculi; instrumentation; stent; endometriosis

• Obstruction
• Reflux
• Primary megaureter (“beak” sign)

• Tumor: TCC; adenocarcinoma; squamous cell carcinoma; metastases (pheochromocytoma)
• Extrinsic masses: BPH; uterus (fibroids); etc.
• Other: calculus; thrombus; ureterocele (pseudoureterocele due to inflam/ tumor); foreign bodies

• adjacent to UVJ; ↑ vesicoureteral reflux

• Clinical: transitional cell (90% malignant); risks = azo-dyes; phenacetin; cyclophosphamide; focal thickening of bladder wall; perivesical spread; LAD (> 10 mm)
• Staging:
  • Stage A: limited to mucosa + submucosa
  • Stage B1: superficial muscular layer
  • Stage B2: deep muscular layer
  • Stage C: perivesical fat
  • Stage D: seminal vesicles, prostate, or rectum

• Contusion: interstitial
• Extraperitoneal: due to pelvic fracture, dissection into retroperitoneum + scrotum + thigh
• Intraperitoneal: usually blunt trauma with distended bladder; DX requires adequate bladder distention (> 250 ml)

• Schistosomiasis (↑ squamous cell carcinoma)
• CA; cyclophosphamide (cytoxan); calculus
• Alkaline encrusting cystitis
• Radiation
• TB

• Anterior = penile + bulbous (penoscrotal junction)
• Posterior = membranous (between inferior margin of verumontanum + tip/ cone of bulbous urethra) + prostatic
  • Cowper’s glands: contained within membranous urethra with ducts entering the bulbous urethra
  • Glands of Littré: located primarily along dorsal penile urethra → infections (gonococcus; chlamydia)

• Clinical: risks = pelvic trauma (especially multiple pelvic fractures); absence of blood at meatus does not exclude urethral injury → RUG
• Subtypes:
• Type I: posterior urethra stretched
• Type II: posterior disruption (above urogenital diaphragm)
• Type III: anterior + posterior disruption
• Type IV: bladder neck injury with extension to urethra
• Type IVa: periurethral extravasation with intact urethra
• Type V: anterior disruption (“saddle” injury); ↑ bulbous urethra

• Clinical: most often acquired due to infection of Skene’s glands; ↑ posterior wall; SXS = dysuria + dribbling + dyspareunia (3 D’s);

TX = surgical resection (diverticulectomy)

• Radiographic: focal outpouching along posterior urethra; impression along inferior bladder (= “male prostate”); best seen on MRI
• Complications: infection; calculi; CA (squamous cell)

• Trauma
• Inflammatory; infections (prostatitis; phlegmon; etc.)
• Calculus
• BXO (= balanitis xerotica obliterans): variant of lichen sclerosis et atrophicus (white plaques) → phimosis/ meatal stenosis; premalignant (penile squamous carcinoma)

• ↑ cryptorchidism (30%) + inguinal hernias (10%)

• Fibroepithelial polyp: solitary; pedunculated; attached near veru montanum; ↑ child/ young adult
• Transitional cell papilloma: ↑ prostatic/ bulbomembranous urethra; ↑ bladder papillomas; older adults
• Adenomatous polyp: ↑ young men; adjacent to veru montanum
• Penile squamous papilloma / condyloma acuminata: verrucous lesion in penile urethra; associated with cutaneous disease

• Squamous cell carcinoma (70%): distal 2/3 of urethra; risks = venereal disease; ↑ stricture (> 80%)
• TCC (10-20%): posterior 1/3 of urethra; ↑ multifocal
• Adenocarcinoma (10-20%): arise from periurethral glands (Skene; female) and glands of Cowper/ Littré (male)

• Clinical: seminomas → orchiectomy + XRT; nonseminomas (radioresistant) → orchiectomy + chemotherapy
• Staging:
  • Stage I: limited to testes and spermatic cord
  • Stage II: lymph nodes below the diaphragm
  • Stage III: lymph nodes above the diaphragm
    • A: lymph nodes only
    • B: extranodal mets
• Lymphatic spread: along gonadal veins → renal hilar nodes; external iliac nodes → para-aortic nodes
• Hematogenous spread: uncommon except for choriocarcinoma
• Cryptorchidism: located from inferior renal pole to superficial inguinal ring; ↑ risk of torsion (↑ 10x) + malignancy (↑ 50x); usually atrophic

• Inguinal hernia
• Inflammatory mass such as infection, sarcoidosis
• Benign neoplastic processes such as adenomatoid tumor, epidermoid inclusion cyst
• Malignant processes such as soft tissue sarcomas, mesothelioma of the tunica, lymphoma, and metastatic disease.

• Calcification of tunica albuginea of corpora cavernosa
• Idiopathic, older men (> 45 yrs old)

• U/S → hyperechoic central gland = transitional + central zones
• Transition zone (5%): periurethral → BPH
• Central zone (25%): ejaculatory ducts
• Peripheral zone (75%): carcinoma (> 80%); hypoechoic

• periurethral transitional zone; enlarged, lobulated gland; cystic degeneration; Ca2+; elevation of bladder base; bladder wall thickening and trabeculation

• Midline:
  • Mullerian duct: larger; extend superiorly
  • Utricular cyst: smaller; communicate with urethra; ↑ hypospadias
  • Ejaculatory duct cyst: acquired; due to obstruction
• Eccentric:
  • Cystic prostatitis/ carcinoma
  • Cystic BPH
• DDX = seminal vesicle cysts → unilateral; ↑ ipsilateral renal agenesis (= Zinner syndrome) > cystic renal disease (APKD), renal ectopia, duplication, ectopic renal insertion

• Clinical: # 2 male CA; enlarged gland with nodules; periprostatic stranding; regional nodes; direct extension to seminal vesicles, bladder; mets to axial skeleton
• Radiographic: hypoechoic; ↓ T2 lesions in peripheral gland (DDX = prostatitis; fibrosis; hemorrhage)

• Stage A: nonpalpable
• Stage B: confined to prostate
• Stage C: capsular involvement
  • 1: invasion
  • 2: penetration
  • 3: seminal vesicles
• Stage D: metastases
  • D1: pelvic LN
  • D2: bone; distant LN
• Treatment: Stage A/B → radical prostatectomy +/- XRT; Stage C/D → hormone therapy +/- XRT

• Ascites: serous; due to CHF, cirrhosis, hypoproteinemia, venous obstruction; accumulates in greater peritoneal space; density = 10-15 HU
• Exudative ascites: pancreattis → accumulates within lesser sac; peritonitis; bowel perforation
• Hemoperitoneum: density > 30 HU; “sentinel bleed” → accumulates at site of hemorrhage
• Pseudomyxoma peritonei: due to appendiceal mucocele or mucinous cystadenocarcinoma of the ovary (> urachal/ endometrial CA); peritoneum filled with gelatinous mucin; Ca2+

• due to bowel perforation, pneumothorax, or mechanical ventilation

• Peritoneal carcinomatosis:
  • Etiologies: ovarian, pancreatic, gastric, and colon carcinoma
  • Radiographic: malignant ascites; tumor nodules/ Ca2+ → bowel wall nodularity; mesentery; “omental cake”; pouch of Douglas (“Blumer’s shelf); adnexa/ ovaries (Krukenberg tumor)
• Peritoneal (cystic) mesothelioma: 20-40% in abdomen; ↑ women 30-40 years; irregular thickening of peritoneal surfaces; multilocular cysts; ascites; bowel compression without obstruction
• Mesenteric lipodystrophy (= retractile mesenteritis): fat-density mass with tethering/ kinking/ angulation of adherent bowel loops

• Clinical: complications of trauma or surgery; pancreatitis; bowel perforation; commonly located within pelvis, subhepatic and subphrenic spaces
• Radiographic: loculated fluid collection; thickened walls; gas; thickening of fascia; obliteration of fat planes; ascites; pleural effusions

• Abscess
• Loculated ascites
• Pancreatic pseudocyst
• Ovarian cyst/ tumor
• Cystic teratoma: fat, water, Ca²⁺
• Enteric duplication cysts: lined by GI mucosa
• Lymphocele: complication of surgery / trauma
• Cystic lymphangioma: mesenteric / omental

• Ectopic pregnancy: adnexal/ tubal ring
• TOA: tubo-ovarian abscess
• Endometrioma
• Ovarian neoplasms
• Ovarian cysts
• Extra-GU origin: abscess; urinoma; duplication/ mesenteric cyst; etc.

• Pathology: lymphadenopathy: > 10 mm in abdomen and pelvis; > 6 mm in retrocrural and porta hepatis regions
• Hodgkin’s lymphoma: 40% of total; contiguous spread
• Non-Hodgkin’s lymphoma: 60% of total; noncontiguous spread; ↑ GI involvement

• Infection: MAI > TB (↑ AIDS), histoplasmosis
• Whipple’s disease: glycogen deposition
• Tumors: lymphoma (post-therapy); nonseminomatous testicular CA; mucinous adenoCA (rare)

• Hemoperitoneum: density (30-45) HU; (60-80) HU → active bleeding (> 100 HU with contrast); “sentinel clot” → adjacent to injured organ (> 60 HU); free intraperitoneal contrast → bowel/ bladder perforation
• Pneumoperitoneum: perforated viscous; PTX; mechanical ventilation; post-op
• Subcapsular hematomas: crescentic → flatten parenchyma
• Lacerations: jagged, linear low density areas
• Intraparenchymal hematomas: rounded, low density areas

• ST-encasement of retroperitoneal vessels/ ureters without anterior displacement (DDX = lymphoma); prominent enhancement
• Drugs: methylsergide; hydralazine
• Lymphoma
• Metastases: lung; breast; carcinoid
• Other: AAA; trauma; surgery; instrumentation
• Ormond’s disease: idiopathic

• MFH (#1)
• Liposarcoma (#2)
• Other: leiomyosarcoma; metastases; RCC/ adrenal extension

• XGP
• Neural tumors
• Lymphangioma; hamangioma; lipoma
• Teratoma (dermoid)

• Associated w/
  • aortic aneurysms
  • inflammatory bowel dz
  • urinomas
  • retroperitoneal hematomas
  • aortic and iliac graft procedures
  • infections
  • ergot alkaloids
  • sclerosing cholangitis
  • fibrosing mediastinitis

• massive, usually bilateral, hemorrhage into the adrenal glands caused by fulminant meningococcemia

• Neoplastic
  • Testicular (particularly teratocarcinoma)
  • Epidermoid carcinoma of GU tract
  • Lymphoma
  • Leiomyosarcoma
• Infectious
  • Whipple's Dz
  • MAI