What is the differential diagnosis for a patient with increased abdominal girth?

Differential Diagnosis of Increased Abdominal Girth

Immediate Life-Threatening Considerations

In women of reproductive age presenting with increasing abdominal girth, ovarian pathology—particularly ovarian cystadenomas and germ cell tumors—must be excluded first, as these are the most common causes of large abdominal masses in this population and can reach enormous sizes over months. 1, 2

Critical Cardiovascular Causes

• Heart failure with volume overload presents with increased abdominal girth, right-sided abdominal fullness, discomfort or tenderness, and increasing abdominal distention or ascites (in the absence of primary hepatic disease). 3
• Accompanying features include peripheral edema, increased jugular venous pressure, hepatojugular reflux, S3 gallop, pulmonary rales, and clinically significant weight gain (>3-4 lb in 3-4 days). 3
• Liver enlargement from hepatic congestion is a supporting physical finding. 3

Structural Abdominal/Pelvic Pathology

Gynecologic Causes (Women)

• Ovarian cystadenomas are the leading cause of large abdominal masses in young women and can present as slowly enlarging masses over months to years. 1, 2
• Mature cystic teratomas (dermoid cysts) are high on the differential for persistent ovarian masses in young women, as up to 70% of adnexal lesions in this population are functional cysts that resolve spontaneously, but persistent masses over 9 months suggest dermoids or cystadenomas. 2
• Germ cell tumors are the leading malignant consideration in women under 35 years with ovarian masses, particularly when constitutional symptoms like weight loss are present. 1
• Uterine leiomyomas (fibroids) cause increased abdominal girth and are common structural causes of abnormal uterine bleeding in premenopausal women. 3, 4
• Adenomyosis frequently coexists with fibroids and presents with heavy menstrual bleeding, dysmenorrhea, and dyspareunia, commonly affecting women in their 40s. 4
• Endometrial polyps and endometrial hyperplasia are structural causes that may contribute to abdominal symptoms. 3

Gastrointestinal Causes

• Pseudomyxoma peritonei syndrome presents with gradual expansion of mucoid tumor and fluid within abdominopelvic regions, with increasing abdominal girth being the second most common presentation (23% of cases). 5
• This condition results from perforated appendiceal adenoma and may present with new-onset hernia (14% of cases, predominantly inguinal). 5
• Gastric subepithelial masses from extramural compression by tumors, abscesses, pancreatic pseudocysts, renal cysts, aneurysms, or enlarged lymph nodes can appear as abdominal masses. 3
• Severe intestinal dysmotility causes marked pooling of gut contents, particularly in the small bowel, leading to increased abdominal girth and antero-posterior abdominal diameter. 6
• Ascites from primary hepatic disease, peritoneal carcinomatosis, or other causes presents with abdominal distention. 3

Metabolic/Endocrine Causes

• Growth hormone excess (acromegaly/gigantism) in children and young people presents with increased BMI, increased appetite, and acanthosis nigricans in X-linked acrogigantism. 3
• Obesity and metabolic syndrome with increased body mass index (BMI ≥25-30) is associated with increased abdominal girth and measures of abdominal girth are convincing evidence of body fatness. 3

Iatrogenic/Drug-Related Causes

• Abdominal hypertrophy syndrome (Palumboism) affects bodybuilders and athletes engaged in prolonged usage of growth hormone, insulin, and other anabolic agents, characterized by significant enlargement and distension of the abdomen. 7
• Proposed mechanisms include visceral adiposity, organomegaly, and altered collagen synthesis from high-dose anabolic steroids. 7

Functional Gastrointestinal Disorders

• Irritable bowel syndrome (IBS) presents with bloating that may or may not be accompanied by objective increase in abdominal girth (distention). 8
• Bloating alone without distention is associated with visceral hypersensitivity, while distention is observed more in hyposensitive individuals, particularly in IBS-constipation subgroup. 8

Diagnostic Algorithm

Initial Evaluation

1. Pregnancy test in all reproductive-age women to rule out pregnancy. 4
2. Combined transabdominal and transvaginal ultrasound with Doppler is the mandatory first imaging study to determine if the mass is ovarian in origin, assess for solid components, papillary projections, and vascularity patterns. 1, 2
3. Contrast-enhanced CT chest, abdomen, and pelvis if ultrasound suggests malignancy or if hemoptysis, weight loss, or other constitutional symptoms are present (88-94% sensitivity for serious intra-abdominal pathology). 1

Laboratory Testing

• Tumor markers: AFP and hCG for germ cell tumors (in women under 35), CA-125 for epithelial ovarian neoplasms. 1, 2
• BNP or NT-proBNP if heart failure is suspected (BNP >500 pg/mL or NT-proBNP >2000 pg/mL suggests acute decompensated heart failure). 3
• Complete blood count to assess for anemia. 1
• Thyroid-stimulating hormone and prolactin levels in appropriate clinical context. 4

Advanced Imaging

• MRI pelvis with and without IV contrast if ultrasound findings are indeterminate, as MRI provides 91% overall accuracy for diagnosing malignancy and is superior to CT for characterizing complex adnexal masses. 2
• Diffusion-weighted imaging should be included in MRI protocols to improve sensitivity and specificity for uterine pathology. 3

High-Risk Features Requiring Urgent Intervention

• Solid components with internal vascularity on Doppler suggest malignancy. 1, 2
• Papillary projections or thick irregular septations suggest malignancy. 1, 2
• Presence of ascites suggests peritoneal dissemination. 1, 2
• Unintentional weight loss >5% body weight over 2 months indicates organic pathology. 1
• Hemoptysis with abdominal mass suggests pulmonary metastatic disease. 1

Critical Management Pitfalls

• Never perform FNA on suspected ovarian masses due to risk of malignant cell spillage if cancer is present. 2
• In middle-aged women with increasing abdominal girth, ovarian disorders must always be considered and appropriate diagnostic testing performed. 9
• Abdominal complaints after bariatric surgery require consideration of alternative diagnoses beyond surgical complications or unhealthy eating habits. 9
• Gynecologic oncology consultation is mandatory if imaging suggests malignant features (solid components, ascites, papillary projections). 1