Differential Diagnosis for Left Lower Quadrant Pain and Hematoma-like Lesion

Single Most Likely Diagnosis

• Diverticulitis: Given the location of the pain and the hematoma-like lesion in the left lower quadrant, diverticulitis is a strong consideration. It is a common condition in adults, especially after the age of 40, and can cause localized pain and inflammation that might resemble a hematoma.

Other Likely Diagnoses

• Colonic Neoplasm: A tumor in the colon could cause pain and, if it involves the bowel wall, could lead to a hematoma-like appearance due to bleeding or necrosis.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic inflammation of the bowel, leading to pain and potentially a mass or lesion that could be mistaken for a hematoma.
• Left Ovarian Cyst or Torsion: In females, an ovarian cyst can cause lower abdominal pain, and if it ruptures or undergoes torsion, it might present with a hematoma-like lesion.
• Nephrolithiasis: Kidney stones can cause severe pain that radiates to the lower abdomen and, although less likely, could potentially cause a hematoma if there's associated bleeding.

Do Not Miss Diagnoses

• Abdominal Aortic Aneurysm (AAA): Although less common in a 41-year-old, an AAA can cause abdominal pain and, if ruptured, could lead to a hematoma. Given the patient's heart failure with reduced ejection fraction, the risk of vascular diseases might be higher.
• Intra-abdominal Hemorrhage: Spontaneous bleeding into the abdominal cavity can occur due to various reasons, including anticoagulation therapy (if the patient is on it for heart failure), and would be life-threatening.
• Mesenteric Ischemia: This condition, which involves insufficient blood flow to the intestines, can cause severe abdominal pain and could potentially lead to a hematoma-like lesion due to bowel infarction.

Rare Diagnoses

• Wegener's Granulomatosis: A rare autoimmune disorder that can cause inflammation of blood vessels and lead to a variety of symptoms, including abdominal pain and masses.
• Ehlers-Danlos Syndrome: A genetic disorder that affects the body's connective tissue and can lead to easy bruising, poor wound healing, and potentially abdominal pain or hematomas due to vascular fragility.
• Sickle Cell Crisis: If the patient has sickle cell disease, a crisis could cause abdominal pain and potentially a hematoma-like lesion due to vaso-occlusive episodes affecting abdominal organs.