Thursday, 24 August 2017

Diagnostic Challenge of Renal Angiomyolomas


Renal angiomyolipomas (AML) are benign neoplasms, arising from perivascular epithelioid cells. They are very rare tumors and are strongly associated with tuberous sclerosis. Their incidence in the general population is very low, approximately 0.3-2.4%, and were described as first time in 1880 by Bourneville and Brissard. Most patients with renal AML are asymptomatic. The dreaded complication is spontaneous retroperitoneal hemorrhage. Due to that, prophylactic surgery is recommended to prevent hemorrhage in patients with tumor size larger than 8 cm in diameter. Here we describe a young woman who presented with severe abdominal pain and was found to have underlying renal angiomyolipoma complicated with active hemorrhage.

A 21-year-old woman presented with sudden onset right flank and right lower quadrant abdominal pain that began when she woke up that morning. She described the pain as sharp, knife like, non-radiating, 7/10 in intensity, aggravated by minimal movement and relieved by lying still, associated with nausea and 1 episode of non-bloody vomiting. She also reported an episode of syncope earlier that day, when she lost consciousness for few seconds. She denied hitting her head, seizure like activity or post syncopal confusion. Patient denied abdominal injury, recent illness, foreign travel, fever, chills, change in bowel or bladder habits and vaginal discharge. She had no significant past medical or surgical history. She was not taking any medications. She was never married or pregnant. Her menstrual cycles were irregular. Last menstrual period was 20 days prior to admission. She reported being sexually active and used condoms for protection. She denied any significant family history. On physical examination, patient was afebrile and vitally stable. She had severe tenderness to palpation in the right upper and lower abdomen and right flank. Normoactive bowel sounds were present. Attending to blood tests, complete blood count and comprehensive metabolic panel were within normal limits except for a normochromic normocytic anemia with hemoglobin of 11.6 g/dl and minimal leukocytosis (WBC 11.1 u/kL). Urine analysis and urine pregnancy test were negative. Chest x ray was unremarkable. CT scan of abdomen and pelvis with contrast (Figure I) was obtained, which revealed a 17.5 x 13.8 x 13.1 cm retroperitoneal mass arising from the right kidney.

The mass was composed of fatty and soft tissue components along with blood products. A differential diagnosis of ruptured angiomyolipoma and malignant tumors such as liposarcoma were considered. Considering patient’s young age, acuity of symptom onset and the fact that the mass arised from the kidney, the diagnosis of renal angiomyolipoma was determined to be more likely. The patient had no stigmata of tuberous sclerosis on physical examination. Initially, we decided to proceed with conservative management but within a time span of 12 hours, patient’s hemoglobin decreased to 9.5 g/dl. Interventional radiologist was consulted for the management of ongoing bleeding. Emergency arteriogram with super selective embolization of AML with alcohol and coil was performed through the lower pole of right renal artery. A CT guided biopsy of right renal lesion was also performed. Histological examination confirmed our diagnosis of renal angiomyolipoma. The patient was monitored in Intensive care unit for few more days and was subsequently discharged as she improved. She is planned to undergo elective resection of angiomyolipoma at a future date. 

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