Cystic angiomyolipoma of the kidney: a clinicopathologic description of 11 cases

Abstract

This report deals with 11 examples of renal angiomyolipomas (AML) which appear to include an epithelial element as a part of the neoplasm in the form of gross or microscopic cysts-usually both. There were seven females and four males between the ages of 20 and 70 years with mean age of 45 years. Three of these were known to be symptomatic: intermittent flank pain and gross hematuria for 2 months; recurrent hematuria both before and after flank trauma and a third patient with acute abdomen due to a ruptured tumor blood vessel. Cysts were described in three of the six cases where radiographic data were available. Seven tumors were in the right kidney and four in the left. In gross descriptions, cysts were mentioned in seven and they ranged from 6.0 to 2.0 cm with a median and mean maximal diameter of 5.0 and 4.0 cm, respectively. Microscopically, virtually all of the tumors included multiple smaller cysts and these were lined by flat, cuboidal or columnar epithelium and occasionally hobnail epithelium. There was usually a subepithelial collar of poorly differentiated cells, but the solid element of all tumors was myomatous angiomyolipoma; only one case had any adipose tissue. A dominant histological feature was the prominent lymphatic channels-identical to those of lymphangiomyomas and myomatous or triphasic AMLs. They are much more conspicuous in these cystic cases. Immunohistochemically, all tumors tested were reactive with actin, desmin and HMB-45, with the latter being more intensely positive in the subepithelial collars. Estrogen and progesterone receptors were usually positive, also. The behavior of these lesions appears to be no different from that of other AMLs.

Cathepsin K expression in the spectrum of perivascular epithelioid cell (PEC) lesions of the kidney

“…It is a smooth muscle-predominant tumor in which are embedded epithelium-lined cysts with a compact subepithelial 'cambium-like' layer of stromal cells positive for HMB-45, estrogen and progesterone receptors. [17][18][19] Lymphangioleiomyomatosis of the renal sinus is a plaque-like proliferation in the wall of the renal pelvis. All three cases reported to date also had renal angiomyolipomas, but in only one of them was an association with pulmonary lymphangioleiomyomatosis observed.…”

Cystic angiomyolipoma of the kidney in a patient with chronic renal failure: a very rare variant

“…Among the published cases in the literature regarding cystic angiomyolipomas, no cases of malignant transformation have been reported on follow-up, even among patients who had received nephron-sparing surgery. [5][6][7] Thus, according to the published literature, cystic angiomyolipomas seem to have a benign disease course similar to classic angiomyolipomas. [5][6][7][8] The differential diagnosis of cystic angiomyolipomas involves distinguishing between mixed epithelial and stromal tumors (previously classified as cystic hamartomas of the renal pelvis, adult mesoblastic nephroma, or renal pelvic or cortical hamartomas), cystic nephroma, multilocular cystic renal cell carcinoma, liposarcoma and vascular malformations.…”

“…[5][6][7] Thus, according to the published literature, cystic angiomyolipomas seem to have a benign disease course similar to classic angiomyolipomas. [5][6][7][8] The differential diagnosis of cystic angiomyolipomas involves distinguishing between mixed epithelial and stromal tumors (previously classified as cystic hamartomas of the renal pelvis, adult mesoblastic nephroma, or renal pelvic or cortical hamartomas), cystic nephroma, multilocular cystic renal cell carcinoma, liposarcoma and vascular malformations. [7,8] Although mixed epithelial and stromal tumors of the kidney are thought to be more common in females (or males with estrogen exposure), [8][9][10] our patient did not have a history of estrogen exposure.…”

“…[5][6][7][8] In our case, the patient was diagnosed with cystic angiomyolipoma after being admitted to our outpatient clinic with lower urinary tract symptoms mostly relating to prostatic obstruction.…”

“…[4] Cystic angiomyolipomas, or angiomyolipomas with epithelial cysts, are extremely rare lesions, and fewer than 20 cases have been reported in the literature according to the Pubmed database. [5][6][7][8] Herein, we report a very rare case of cystic angiomyolipoma of the kidney and discuss the clinical and pathological findings.…”