Received date:: January 15 2017; Accepted date:February 02, 2017;Published date:February 06, 2017
Hemangiopericytoma arising from the greater omentum is very rare, and only few case reports were found in the English literature. Here we report a case of hemangiopericytoma arising from the greater omentum with pelvic metastasis.
The case was a 45-year-old male patient admitted to our hospital with abdominal pain and swelling. Abdominal ultrasound and computer tomography detected a huge heterogeneously enhancing predominantly solid central abdominal mass with cystic changes. Laparotomy and excision of huge freely mobile highly vascularized mass arising from the greater omentum & multiple deposits on the anterior wall of the rectum was performed. Histological findings confirmed a diagnosis of hemangiopericytoma of the greater omentum with secondary deposits in the pelvis.
Hemangiopericytoma arising from the greater omentum is a very rare tumor originating from Zimmerman’s pericyte. Stout and Murray described the first reported case of hemangiopericytoma arising from omentum in 1942 . Pericytes are primitive cells that have contractile behaviors and regulate the flow of blood through capillaries. Even though hemangiopericytoma can arise anywhere, the predominant sites of origin are the retroperitoneum, the pelvic cavity and the lower extremity . Hemangiopericytoma originating from the greater omentum with metastasis to other areas is very rare; this is one of the few case reports of hemangiopericytoma arising from the greater omentum with pelvic metastasis throughout the English literature. We report a case of hemangiopericytoma arising from the greater omentum with metastasis to the pelvis.
A 45-year-old Ethiopian male patient was admitted to our hospital with a complaint of abdominal pain and swelling of 1-year duration. The pain was dull aching and periumbilical whereas the swelling was initially epigastric and later progressed to involve the whole abdomen and associated with early satiety and constipation. On physical examination, the abdomen was full with a palpable mass measuring 17cm by 14cm which is mobile, firm, irregular, non-pulsatile & palpable lower border. Abdominal ultrasound and computer tomography of the abdomen showed heterogeneously enhancing huge central abdominal mass; predominantly solid with central cystic changes measuring 26cmx21cmx10cm (Figure1). No ascites, liver metastasis or lymphadenopathy detected on imaging.
With a preoperative diagnosis of huge abdominal mass arising from the greater omentum, laparotomy was performed and huge freely mobile highly vascularized mass arising from the greater omentum & multiple deposits on the anterior wall of the rectum was found (Figure 2&3) There was also a 3×2 lymph node on the omentum. No evidence of liver metastasis. The tumor was excised and the lymph node and the deposits in pelvis were biopsied.
The resected tumor was predominantly solid mass with central areas of cystic degeneration, with largest diameter of 16 cm, measured 16 x 13 x 9 cm, weighed 2.1 kilograms and was encapsulated with central necrosis and areas of hemorrge. On histologic examinations of both the mass and pelvic deposits, hematoxylin-eosin staining showed spindle cells growing around vascular endothelial cells. On high power field, there was high mitotic activity. Immunohistochemical studies demonstrated that the tumor was positive CD34, factor-IIIa, and HLA-DR. These findings confirmed a diagnosis of high grade hemangiopericytoma with metastasis. The patient was transfused with 02 units of whole blood postoperatively and discharged improved on the 8th postoperative day. Adjuvant chemotherapy was offered and he is on his 4th month on follow up with no evidence of recurrence.
Hemangiopericytoma arising from the greater omentum is extremely rare and we found few reports of malignant hemangiopericytoma of the greater omentum with metastasis in the English literature. Late presentation of our patient might have allowed the tumor to attain a huge size.
Recent reports suggested that malignant hemangiopericytoma is suspected if tumor size is more than 5 cm, a high mitotic index with more than four mitoses per ten high power fields, and necrosis and hemorrhage within the tumor . According to the reported cases, tumor size and mitotic index were associated with tumor recurrence after resection .
Although effective chemotherapeutic and molecular targeting therapy is not established to date, systemic adjuvant chemotherapy is additional treatment for malignant hemangiopericytoma with peritoneal metastasis . Even though surgical resection provides the only chance for cure for patients with low grade malignancy, additional adjuvant chemotherapy offers benefit for patients with advanced disease like ours.
Stout AP, Murray MR (1942) Hemangiopericytoma: A Vascular Tumor Featuring Zimmermann's Pericytes. Ann Surg 116: 26-33. [crossref]
Enzinger FM, Smith BH (1976) Hemangiopericytoma. An analysis of 106 cases. Hum Pathol 7: 61-82. [crossref]
Kempson RL, Fletcher CDM, Evans HL, Hendrickson MR, Sibley RK, et al. (1998) Atlas of tumor pathology: tumors of the soft tissue, 3rd series. Washington DC: Armed forces instate of pathology pp 371-377.
Goldberger RE, Schein CJ (1968) Hemangiopericytoma of the omentum. Report of a case with a unique presentation and review of the literature. Am Surg 34: 291-295. [crossref]
Imachi M, Tsukamoto N, Tsukimori K, Funakoshi K, Nakano H, et al. (1990) Malignant hemangiopericytoma of the omentum presenting as an ovarian tumor. Gynecol Oncol 39: 208-213. [crossref]
Cajano P, Heys SD, Eremin O (1995) Haemangiopericytoma of the greater omentum. Eur J Surg Oncol 21: 323-324. [crossref]