[915] Significance of Hormone Receptor and Ki-67 Labeling Index in Angiomyolipoma: A Clinicopathological and Immunohistochemical Study of 23 Cases

Meeran Kim, Hyun-Jung Lee, Min-Kyung Yeo, Young-suk Lee, Dae Young Kang. Chungnam National University School of Medicine, Daejeon, Korea

Background: Angiomyolipoma (AML) is an uncommon renal tumor. Classically, it is composed of three distinct components; mature adipocytes, smooth muscle cells, and thick-walled blood vessels. It has recently been referred to as one of the perivascular epitheliod cell tumor (PEComa) family. We investigated hormonal receptor expression, other immunohistochemical (IHC) profiles (HMB-45, Bcl-2, and Ki-67 labeling index), and clinical information of 23 cases of AML.
Design: All the AML cases were retrieved from the archives of the CNUH from 2000 to 2010. 23 cases were found and among these, 3 cases underwent radiofrequency ablation were excluded for IHC study. Two tissue microarrays for each case consists of 2mm cores and IHC study for estrogen receptor alpha, progesterone receptor, HMB-45, Bcl-2, and Ki-67 was performed. Statistical analyses were done using the t test and ANOVA test with p values <0.0.5 considered statistically significant.
Results: Among 23 cases, none of them was related to the tuberous sclerosis complex. 17 of them discovered the renal mass incidentally while their routine examination; 5 of them had flank pain; 1 had gross hematuria. Other clinical features are remarked on the Table1. The results of IHC study revealed as follows: ER (6/20, 30%) PR (11/20, 55%) HMB-45 (19/20, 95%) Bcl-2 (17/20,85%) ki-67 labeling index (13/20, 65%, range 1∼20%). One case showed atypical histopathologic feature consistent with epithelioid AML. This case showed a large mass (9cm) and metastatic lesion to the mediastinum was diagnosed radiologically. No biopsy was done from the mediastinal mass. This case showed high Ki-67 labeling index (20%) and positive ER and PR expression as well as HMB-45 and Bcl-2.

Clinical and Pathologic Features of Angiomyolipoma of the Kidney.
Mean age (ys) (range)54.8 (36-75) 
Tumor locationRight kidney15
 Left kidney8
Size (cm) (range)6.4 (1.5-22) 
Pathologic diagnosisClassical AML22
 Epithelioid AML1

Conclusions: Although, some previous reports have claimed that high Ki-67 index correlates with the epithelioid AML, we found no relationship between them. One epithelioid AML case from our study showed high Ki-67 labeling index, but some of classical AML also showed Ki-67 labeling index more than 10% of the cells. However, it was strongly associated with the ER and PR expression (p<0.05). This suggests the possibility of relationship between hormonal receptor expression and tumor growth.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 101, Wednesday Morning


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