Retroperitoneum Adrenal glands

Adrenal Gland sonography Ability to visualize depends on: Patient body habitus Operator experience High resolution equipment Right adrenal gland: Best evaluated intercostally,midaxillary line Remember suprarenal location/IVC relationship Left adrenal gland: Best evaluated intercostally through spleen/kidney Epigastrium and suprarenal location More difficult to visualize than right adrenal

Infectious diseases Tuberculosis: Histoplasmosis: Acutely-bilateral diffuse enlargement Inhomogenous- due to caseous necrosis Chronically-more atrophic and calcified Histoplasmosis: Adrenal calcifications The 2 most common causes of adrenal calcifications in the adult

Benign adrenal neoplasms Adenomas Most common adrenal tumor-incidentalomas Found in 9% of autopsies Incidence: Increases with age Hypertensive individuals Diabetics Hyperthyroidism RCC Hereditary colorectal adenomatosis

Adenomas No specific ultrasound features (> 1 cm) Nonhyperfunctioning More common Asymptomatic-incidentally found Hyperfunctioning Present clinically with symptoms related to excess hormone production Cushing’s Syndrome Conn’s disease Refer to page 435 figure 11-9

Hyperfunctioning adenomas Cushing’s syndrome: Excessive cortisol excretion Hyperplastic glands Characterised by: Truncal obesity Hirsutism Amenorrhea Hypertension Weakness Conn’s disease: Excessive aldosterone excretion Characterised by: Hypertension Muscular weakness Tetany ECG abnormalities

Outcome of adrenal masses Adrenal masses > 6cm Suspicious for malignancy Typically resected Adrenal masses 4-6cm Close imaging followup Or surgical excision Adrenal masses < 4cm Management is based on additional imaging findings CT,MRI,PET-CT may be helpful

Pheochromocytoma Neuroendocrine tumor of the medulla Hyperfunctioning Secrete norepinephrine and epinephrine into blood Clinical manifestations: Hypertension Severe headache Palpitations Tachycardia Excessive perspiration

Pheochromocytomas con’t Seen most frequently in adults 40-60years Rare but curable cause of hypertension Sonographically: 5-6cm in diameter-easily seen More often in right gland Well marginated May be calcified Heterogenous or homogenously solid May have areas of necrosis or hemorrhage

Rare benign adrenal tumors Ganglioneuromas Hemangiomas Teratomas Fibromas Leiomyomas Osteomas Neurofibromas Diagnosis must be made histologically

Malignant adrenal neoplasms Primary Adrenocortical cancer Rare Arises from any layers of adrenal cortex Hyperfunctioning or nonhyperfunctioning Clinical manifestations of excess hormone production in hyperfunctioning tumors Highly malignant Invades adrenal vein,IVC and lymphatics Recurs after surgical excision

Sonographic appearance Variable,depending on size of mass Hyperfunctioning: Smaller when discovered Homogenous echo pattern Nonhyperfunctioning: Heterogenous Central areas of necrosis and hemorrhage Calcifications Well defined lobulated border

Large solid adrenal mass

Solid adrenal mass

Benign VS Malignant Cannot sonographically differentiate between adenomas,carcinoma,pheochromocytoma and metastases Smaller lesions more likely to be benign Larger lesions more likely to be malignant if: Hemorrhage Necrosis Calcifications Duplex and color doppler useful to R/O venous tumor extension

Metastases Adrenal gland -4th most frequent site of metastatic disease After lung ,liver and bone Most common primary tumors to spread to adrenal gland: Lung Breast Melanoma Kidney Thyroid Colon

Sonographically Solid,typically heterogenous Inhomogeneity due to Necrosis Hemorrhage May be bilateral Ct and MRI help distinguish between adenoma and metastases

Adrenal cysts Rare benign lesions More frequently-3rd to 5th decades May be bilateral More frequently in females Asymptomatic May cause symptoms with growth If large can displace or compress adjacent structures Typical cystic appearance May be pseudocysts

Metabolic disorders Hemochromatosis: Wolman’s disease: Increased iron absorption Leads to mild adrenocortical insufficiency Glands are typically small Wolman’s disease: Rare autosomal recessive Lipid storage disease Infants die within 6 months of life

Adrenal pseudomasses Thickened diaphragmatic crus Accessory spleen Gastric fundus/diverticulum Renal vein Adenopathy Retrocrural or retroperitoneal Hypertrophied caudate lobe of liver Upper pole renal cysts Pancreatic tumors Fluid filled colon between stomach and kidney

Pitfalls Use doppler to exclude vascular structure Change patient position Try another window Give patient water to outline stomach Rescan at end of exam to see if bowel gas has moved

Nonvascular diseases of retroperitoneum Lymphadenopathy: Most common solid retroperitoneal mass Enlarged lymph nodes Benign or malignant causes Infection or lymphoma Most commonly hypoechoic If rounded with loss of echogenic central fat-suspicious Located: Para-aortic Paracaval Mesentery

Lymph nodes Normal lymph node Abnormal lymph node

Nonvascular diseases con’t Metastatic disease Frequently spreads to lymph nodes Appear as solid retroperitoneal masses Primary malignancies Most common malignant retroperitoneal tumor: Lymphoma Other primaries include: Sarcomas High rate of recurrence after surgical excision

Benign retroperitoneal masses Fibromas Schwannomas Neurofibromas Lipomas Fluid collections Hematoma Urinoma ,lymphocele Abscess,pseudocyst CT or MRI needed to define benignity

Retroperitoneal fibrosis Associated with inflammatory AAA-5% Patients more prone to back ache Chronic periaortis Mass(rind of tissue) encases the aorta and common iliac arteries May involve ureters Most common complication Ureteral obstruction and hydronephrosis Regresses after repair of AAA

peritoneum

Sonographic technique Evaluation of peritoneum includes Parietal and visceral peritoneum Mesentery Omentum Peritoneal cavity Graded compression is used to displace bowel Palpation of mass determines compliance and mobility Masses from parietal peritoneum-fixed Masses from visceral peritoneum-mobile

Peritoneum

Ascites Normally 50-75ml of free fluid is in peritoneal cavity Acts as a lubricant Ascites occurs with excess accumulation Transudate Exudate Depends on protein content 90%of cases result of- Cirrhosis Peritoneal carcinomatosis Congestive heart failure TB

Ascites con’t In supine position,free fluid accumulates in Paracolic gutters Pelvis Morison’s pouch These areas should be thoroughly examined if ascites is suspected Ultrasound can characterize ascites as anechoic or particulate Particulate suggests blood ,pus,neoplastic cells

Ascites

Hemoperitoneum Many causes: Trauma Ruptured aneurysm Ruptured ectopic pregnancy Ruptured liver mass Adenoma,hepatoma Post surgical bleeding Spontaneous hemorrhage in patients receiving anticoagulants May appear as anechoic or particulate

Trauma Focused abdominal sonography Detect free intraperitoneal fluid Fluid strongly suggests significant intra-abdominal injury Requires urgent laparotomy

Chyla ascites Lymph accumulates in peritoneal cavity Causes: Trauma Surgery Lymphangioma Lymphoma Intestinal lymphangiectasia Cystic hygroma Appears as particulate ascites Fluid-fluid level-layering of lymphatic fluid

Free fluid vs loculated fluid Conforms to surrounding organs Exhibits acute angles when in contact with bowel loops Loculated fluid: Rounded margins Mass effect Displaces surrounding structures Occur anywhere in abdominopelvic cavity

Mesenteric cysts Intra-abdominal masses discovered incidentally May present clinically with pain if large Or acutely if complications Hemorrhage Rupture Torsion Lymphangiomas Enteric duplication cyst

Peritoneal tumors Generally malignant Metastatic most common Ovary is the primary site usually Other sites Stomach ,colon Breast Pancreas Kidney,bladder Uterus Melanoma of skin

Peritoneal Carcinomatosis Diffuse involvement of the peritoneum with metastatic disease Seeding involves parietal and visceral peritoneum Discrete hypoechoic nodules Irregular masses Hypoechoic rind like thickening of peritoneum Ascites is common Pouch of Douglas,greater omentum,Morison’s pouch right subphrenic space most affected

Non-cardiac chest Effusion and mass

Pleural effusion Excess fluid that accumulates between two parietal layers Visceral and parietal Excessive fluid impairs the ability to breath Easily detected on abdominal ultrasound Liver and spleen imaging reveals pleural effusion My appear anechoic or have echoes within Consolidation causes echoes-solid appearance

Left pulmonary consolidation

Pleural effusion Large effusion

Small pleural effusion

Thoracentesis Intervention used to drain pleural effusions Ultrasound guided

Lung mass

Lung mass

Images from text Chapter 14-peritoneum page 524-544 Chapter 12-retroperitneum page 482 fig 12-46