Hemorrhagic Epithelioid Angiosarcoma of the Peritoneal Cavity Clinically Posing as a Dissecting Abdominal Aortic Aneurysm; A Case Report and Literature Review

摘要

Epithelioid angiosarcoma (EA) is a very rare, malignant, vascular neoplasm that is difficult to diagnose and treat. To our knowledge involvement of the omentum and, or mesentery has been reported in only four other cases.1-4 Angiosarcomas comprise less than 2% of all sarcomas, and sarcomas comprise less than 1% of soft tissue cancers.5-8 Among angiosarcomas, the epithelioid variant is exceedingly rare.8,9 The differential diagnosis for abdominal pain is extensive and includes abdominal aortic aneurysm (AAA), mesenteric ischemia and infarction, peritonitis, and intestinal obstruction. Based on laboratory and imaging studies, inclusion of mesenteric angiosarcoma may be warranted in this list of differentials . Since these neoplasms are readily mistaken for carcinomas and melanomas, immunohistochemical staining is vital to diagnosing these lesions. The patient’s omentum and mesenteric lesions were positive with epithelial marker AE-1/AE-3; the vascular markers CD31, Factor VIII, and CD34; as well as endothelial marker Fli-1 supporting the diagnosis of epithelioid angiosarcoma. Interestingly, the human herpes virus stain was negative. This case demonstrates the importance of considering epithelioid angiosarcoma in the differential diagnosis of patients presenting with progressively worsening abdominal pain and findings reminiscent of a rupured aortic aneurysm. Also challenging is the histopathologic diagnosis of these tumors due to the ‘‘epithelioid’’ features of the neoplastic endothelial cells. Utilizing appropriate immunohistochemical studies can be extremely helpful in this regard. Case Report A 77 year old, obese, Latino male presented to the emergency department (ED) with two weeks complaint of abdominal pain, which became progressively worse. The patient was nauseous, lethargic, had a decrease in appetite but denied any hematemesis and hemtochezia. Pertinent past medical history included ethanol abuse, hypertension and benign prostatic hypertrophy. Upon admission, he was hypotensive (102/70), tachycardic (110), with a respiration rate of 16 breaths per minute. He had a slightly distended, non-tender abdomen. A slight hernia was seen in the abdomen. The physical exam was otherwise normal. Initial laboratory studies revealed an anemia with hemoglobin of 8.2 g/dL and hematocrit of 24.4%. CT scan showed an abdominal aortic aneurysm 5.2 X 5.0 X 7.5 cm, without evidence of hematoma. There was also questionable free fluid in the abdomen which “appeared more dense than urine suggesting…blood” and diverticulosis. Based on these findings, the patient was admitted to the intensive care unit, transfused, and seen by various specialists. The vascular surgeon ruled out dissection of the aneurysm. An angiogram did not show active bleeding. Serial CT scans, with and without contrast, did not show leaking from the aortic aneurysm. The CT scans did show peritoneal fluid extending into the pelvis and around the liver. There was an infiltrative process involving the omental and mesenteric fat, deep to the rectus abdominus muscles, representing either blood or inflammation. Paracentesis was performed, showing blood.Approximately one week prior to presenting to the ED, the patient underwent an outside CT without contrast. The report stated that there wasno leakage from the aneurysm, no ascites nor pneumoperitoneum. Scans through the lower abdomen and upper pelvis showed irregular peritoneal densities within the anterior pelvic peritoneal fat. Multiple diverticulae were noted in the sigmoid colon located posterior and medial to the area of fatty infiltration. Findings were suggestive of diverticulitis vs other inflammatory processes. Neoplastic involvement of the peritoneum was also in the differential diagnosis. There was rapid progression of the disease. In less than one week the patient developed free fluid (blood) in his abdominal cavity.Following hospital admission, the patient underwent a laparotomy where approximately seven liters of blood