abdominal wall mass
TRANSCRIPT
الحمد هلل والصالة والسالم على رسول هللا وعلى اله •
وصحبه وسلّم اجمعين
اللهم انفعني بما علمتني وعلمني بما ينفعني وزدني علما ، •
انك العليم الحكيم
• Praise be to Allah and prayers be upon the Messenger of Allah and his family and companions.
• Oh God, give me the benefit of what you have taught me and teach me what benefits me.
Common Causes
• Inguinal Hernia
• Ventral Hernia
• Umbilical Hernia
• Spigelian Hernia
• Femoral Hernia
• Lumbar Hernia
• Abdominal Wall Abscess
• Sebaceous Cyst
• Lipoma
• Keloid
• Hematoma
• Paraumbilical Varices
• Muscle Asymmetry
• Injection Site
Key Differential Diagnosis Issues
• Physical exam and CT are key in distinguishing among hernias and various abdominal wall masses
• Most masses have characteristic appearance on CT
– Some nonspecific "soft tissue density“ masses require biopsy or excision
Ventral Hernia
• Through midline (linea alba); most common after surgery
• May be off midline at site of incision
Spigelian Hernia
• Through defect lateral to rectus sheath
• Often covered by external oblique muscle and aponeurosis
Lumbar Hernia
• Through defect where abdominal wall muscles insert on iliac crest or thoracolumbar fascia (inferior lumbar triangle)
• Defect in oblique and transverse abdominal muscles, often covered by latissimus dorsi muscle
Abdominal Wall Abscess
• Encapsulated ± gas = abscess
• Diffuse, nonencapsulated = cellulitis
• Also consider enterocutaneous fistula (e.g., from diverticulitis)
Sebaceous Cyst
• Common, usually small spherical or oval, well-encapsulated
• Low density, non-enhancing contents without surrounding infiltration
Lipoma
• Common in subcutaneous tissues and between muscle planes
• Uniform fat density with no visible blood vessels
• Liposarcoma
– More complex appearing with visible blood vessels
– May be of near water attenuation (myxoid elements of tumor)
Hematoma
• Heterogeneous, relatively high density focal mass (becomes more uniformly low density as it lyses)
• More diffuse, without mass effect = ecchymosis
• In response to focal trauma or anticoagulation (look for fluid level within hematoma)
Parumbilical Varices
• Common in severe cirrhosis with portal hypertension
• Serpiginous enhancing structures that connect to falciform ligament
Injection Site
• Common in subcutaneous tissues of anterior abdominal wall and buttocks
• May contain gas, soft tissue density; may calcify (injection site granuloma)
Less Common Causes
• Endometriosis
• Calcinosis Syndromes
• Metastases
• Lymphoma and Leukemia
• Desmoid
• Sarcoma
• Rhabdomyolysis
Endometriosis
• May implant in abdominal wall at site of prior Cesarian section or hysterectomy
• Ask about history of cyclical pain and swelling at site of mass
Calcinosis Syndromes
• Dystrophic: Response to tissue injury, such as implanted medical device; or connective tissue diseases (scleroderma, dermatomyositis, CREST); or severe pancreatitis with fat necrosis (most often in breasts)
Calcinosis Syndromes
• Metastatic: I n patients with calcium-phosphate imbalance (renal failure, milk-alkali syndrome)
• Tumoral calcification: Large globular deposits near joints
Metastases
• Melanoma + renal cell most common
• Mass(es) in subcutaneous fat or muscle
• Often subtle or overlooked on CT; more apparent on PET CT
• May occur at site of surgery (e.g., for gallbladder, renal or colon cancer)
Lymphoma and Leukemia
• Cutaneous T cell lymphoma (also known as mycosis fungoides or Sezary syndrome)
– Skin second most common site of extra nodal lymphoma (after GI tract)
• Leukemia cutis (also known as chloroma, or granulocytic sarcoma)
Desmoid
• Also known as fibromatosis; histologically benign but very aggressive growth
• May occur sporadically, but more often in association with Gardner syndrome
Rhabdomyolysis
• Muscle necrosis in response to crush injury, seizures, statin medications
• Poorly defined and minimally enhancing lesion within skeletal muscle
• Commonly leads to severe renal damage due to release of myoglobin into bloodstream