Angiographic Features of Hamartoma of the Kidney

Hamartoma of the kidney is a rare benign tumor in the absence of tuberous sclerosis. It may be bilateral (1, 5). Often it is a combination of more than one connective tissue element, with either the fatty, fibrous, muscular, or vascular element predominating. Conventional methods of investigation are effective when the fatty tissue is dominant in the neoplasm (1). To date, 7 cases have been reported after aortography (2–4, 6, 7). In the case which follows, renal angiography illustrated some distinctive arteriographic changes that were also noted by Viamonte (8). A 29-year-old female was admitted with a 3-week history of left flank pain and a palpable left kidney mass. The findings of the laboratory examinations were normal. An intravenous pyelogram showed a mass in the superior pole of the left kidney, displacing the collecting system (Fig. 1). A nephrotomogram demonstrated the lesion to be ill-defined superiorly; inferiorly, however, it was sharply delineated from adjacent normal kidney structure. The mass appeared to be in part radiolucent. Selective renal angiography revealed the main renal artery to be of normal caliber. The upper pole branch was markedly dilated, circuitous, and aneurysmal, with abnormal tortuous side branches (Fig. 2, A). There were multiple thin tortuous vessels within the medial inferior part of the mass. The aneurysmal part of the upper pole artery retained the contrast medium for more than nine seconds. There was premature visualization of the veins in the area of the tumor. These veins retained the contrast material beyond the time of maximum filling of the renal vein. During the venous phase, a whorled appearance produced by vessels in the mass resembled the appearance seen in myoma of the uterus. The surface veins appeared to circumscribe the mass (Fig. 2, B and C). The microscopic diagnosis was angiolipoleiomyoma (hamartoma) of the kidney. If additional cases show similar findings, this may serve to differentiate hamartoma from hypernephroma. The apparent changes are: (a) The principal artery supplying the lesion is dilated, tortuous, and multisacculated with many tortuous irregularly dilated branches, lacking normal tapering. The sacculations retain the contrast medium well into the venous phase. (b) The venous phase shows a whorled, “onion peel” appearance presumably related to the myomatous tissue present, (c) Lucent areas in the nephrogram, representing fatty elements, are relatively well defined unlike those produced by necrotic areas in hypernephroma, (d) The appearance of hypernephroma in all phases of angiography is more bizarre than that seen in hamartoma.