A 46-year-old woman comes to the office for evaluation of an abdominal mass. The patient first noticed a small abdominal mass 2 months ago that was not painful and did not cause any issues. However, over the past month, the mass has slowly grown and sometimes causes mild abdominal discomfort. The patient has had no weight loss, nausea, vomiting, or changes in bowel patterns. She underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy for uterine sarcoma 6 years ago. Vital signs are normal. BMI is 32 kg/m². The patient has a large, vertical midline abdominal scar consistent with her prior surgery. There is a small, nontender mass at the midline that is palpable while the patient is supine and increases in size with Valsalva. Bowel sounds are normal; there is no rebound or guarding. Which of the following is the most likely diagnosis in this patient?

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Quizplus · Accepted Answer

11ec25c8_da00_9227_bc81_5378e5c068f2_MD0003_00 This patient has a slowly enlarging abdominal mass at her prior surgical incision site, consistent with an incisional hernia. Incisional hernias occur due to fascial closure breakdown. They are common in patients with obesity (elevated intraabdominal pressure) and a prior vertical or midline incision (increased tissue tension). These 2 factors lead to gradual fascial breakdown; presentation may be delayed for months to years, as in this patient. Incisional hernias can be associated with acute gastrointestinal symptoms if the hernias become very large (mass effect) or bowel incarceration occurs (higher risk with smaller hernia size). However, most patients have an asymptomatic abdominal mass (ie, protruding abdominal contents) that slowly enlarges as the fascial defect expands. The mass may be present when patients lie supine, and discrete fascial edges may be palpable in nonobese patients. In addition, abdominal mass size increases with Valsalva because greater intraabdominal pressure causes more protrusion through the defect. Diagnosis is typically clinical. Abdominal CT scan may be used to identify unclear anatomy (eg, surgical repair planning) or if there is concern for an acute complication (eg, bowel incarceration). Abdominal CT scan (Choice B) Metastatic uterine sarcoma may cause an abdominal mass, but tumor size is not affected by the Valsalva maneuver. In addition, this diagnosis typically has associated systemic symptoms (eg, weight loss). (Choice C) Rectus abdominis diastasis is a bulge between the rectus muscles due to linea alba weakening. However, unlike a true hernia, it has no associated fascial defect; therefore, the abnormality is not palpable while supine. (Choice D) A rectus sheath hematoma may present as an abdominal mass. However, it is usually associated with acute trauma and pain rather than with a slowly enlarging, uncomfortable bulge, as in this patient. In addition, hematoma size does not change with Valsalva. (Choice E) A subcutaneous lipoma is a soft tissue tumor that can appear as an abdominal mass; however, lipomas are not typically located in the midline and do not enlarge with Valsalva. Educational objective: Incisional hernias develop due to fascial closure breakdown and may have a delayed presentation (months-years). Patients typically have a slowly enlarging abdominal mass (ie, protruding abdominal contents) that is palpable while supine and enlarges with the Valsalva maneuver. References: Up and down or side to side? A systematic review and meta-analysis examining the impact of incision on outcomes after abdominal surgery. (http://www.ncbi.nlm.nih.gov/pubmed/23570737) Systematic review and meta-regression of factors affecting midline incisional hernia rates: analysis of 14,618 patients. (http://www.ncbi.nlm.nih.gov/pubmed/26389785) Incidence of and risk factors for incisional hernia after abdominal surgery. (http://www.ncbi.nlm.nih.gov/pubmed/25123379)

A 46-Year-Old Woman Comes to the Office for Evaluation of an Abdominal