Differential Diagnosis for Small Fat Containing Umbilical Hernia with Subcutaneous Sinus Tract and Focal Air Locule

• Single Most Likely Diagnosis
  • Umbilical hernia with incarceration and possible strangulation: This is the most likely diagnosis given the presence of a small fat-containing umbilical hernia, which can become incarcerated and potentially strangulated, leading to the formation of a subcutaneous sinus tract and focal air locule due to necrosis or infection.
• Other Likely Diagnoses
  • Omphalitis with abscess formation: Inflammation of the umbilicus (omphalitis) can lead to abscess formation, which might present with a subcutaneous sinus tract and could potentially contain air, mimicking the described findings.
  • Infected urachal cyst: A urachal cyst that becomes infected could present with similar symptoms, including a subcutaneous mass, sinus tract, and possibly air within the cyst due to infection.
• Do Not Miss Diagnoses
  • Appendicitis with an appendix located near the umbilicus: Although rare, an appendix that is abnormally located near the umbilicus could cause symptoms mimicking an umbilical hernia complication, especially if it ruptures and forms an abscess or fistula.
  • Intestinal perforation: A perforation of the intestine near the umbilicus could lead to air in the soft tissues and formation of a sinus tract, making it a critical diagnosis not to miss due to its high morbidity and mortality.
• Rare Diagnoses
  • Dermoid cyst with infection and sinus tract formation: A dermoid cyst near the umbilicus could become infected, leading to the formation of a sinus tract and potentially containing air, although this would be less common.
  • Patent urachus with intestinal obstruction: A patent urachus could potentially cause intestinal obstruction and lead to the described symptoms, although this condition is rare and usually presents in infancy.