Published online Nov 10, 2018. doi: 10.5306/wjco.v9.i7.162
Peer-review started: July 6, 2018
First decision: August 21, 2018
Revised: August 12, 2018
Accepted: October 23, 2018
Article in press: October 23, 2018
Published online: November 10, 2018
A 42-years-old lady came to our hospital with complaints of abdominal pain and distension of two months duration. The physical examination of the patient revealed large retroperitoneal lump present on the left side of the abdomen.
The clinical diagnosis was a retroperitoneal mass, likely to be malignant in nature.
The differential diagnosis included retroperitoneal sarcoma, renal neoplasm, multicystic kidney, cold abscess, or hydatid cyst.
Routine blood investigations did not reveal any abnormality.
Abdominal computed tomography revealed a large perirenal mass lesion displaying prominent vessels. There were also two fairly well defined, predominantly fat density rounded lesions in the left kidney; the smaller lesion was continuous with the large perirenal mass.
Preoperative image guided biopsy of the retroperitoneal mass suggested liposarcoma.
In view of preoperative pathological diagnosis of liposarcoma, the patient underwent a margin-negative resection of the retroperitoneal mass (multi visceral resection - enbloc excision of retroperitoneal mass with left nephrectomy and segmental descending colectomy).
The final histopathological report of the resected specimen confirmed angiomyolipoma.
AML is a tumor of tri-phasic morphology - blood vessels, smooth muscles, and fat cells. Majority of the AML tumors are benign in nature with almost no malignant potential.
A large exophytic renal AML may be confused with a retroperitoneal sarcoma on a small biopsy specimen. A discordance of the radiological and core biopsy findings in a suspected case of exophytic renal AML must alert the surgeon and a re-evaluation of the case with repeat biopsies may clarify the diagnosis.