[Immunohistochemical study of perivascular epithelioid cell neoplasms].
OBJECTIVE
To study the clinicopathologic features, immunophenotype and genetic changes of perivascular epithelioid cell neoplasms (PEComa).


METHODS
A total of 25 cases of PEComa located in various anatomic sites were selected for immunohistochemical staining (SP or EnVision method). TFE3 fluorescence in-situ hybridization was also performed to determine the TFE3 gene status.


RESULTS
The age of patient ranged from 21 to 61 years (mean = 43 years). The male-to-female ratio was 1: 1.3. Histologically, 22 cases represented conventional angiomyolipomas, composed of a mixture of adipose tissue, spindle element, epithelioid smooth muscle cells and abnormal thick-walled blood vessels in various proportions. Three cases involving lung, soft tissue and broad ligament had subtle but distinctive morphologic features. Nested or sheet-like architecture with epithelioid or spindle cells was observed. Immunohistochemical study showed that HMB 45, melan A, smooth muscle actin and cathepsin K were expressed in 80% (20/25), 88% (22/25), 88% (22/25) and 100% (25/25) of PEComa, respectively. Within positive cases, the average proportion of positive tumor cells was 36%, 41%, 35% and 90% respectively for HMB 45, melan A, smooth muscle actin and cathepsin K. TFE3 was negative in all of the 22 renal and hepatic PEComa studied, while it was positive in the 3 cases of extra-hepatorenal PEComa. None of the 25 cases exhibited evidence of TFE3 gene fusion or amplification.


CONCLUSIONS
Extra-hepatorenal PEComa have distinctive morphologic features and are associated with TFE3 overexpression. Cathepsin K immunostaining demonstrates high sensitivity and specificity in PEComa, better than other commonly employed immunomarkers. This marker is thus useful in diagnosis of PEComa and distinction with other neoplasms.
Department of Pathology, Nanjing Jinling Hospital, Nanjing University, School of Medicine, Nanjing 210002, China.
Qiu-Yuan
QY
Xia
Qiu
Q
Rao
Qin
Q
Shen
Biao
B
Liu
Li
L
Li
Qun-Li
QL
Shi
Shan-Shan
SS
Shi
Bo
B
Yu
Ru-Song
RS
Zhang
Heng-Hui
HH
Ma
Zhen-Feng
ZF
Lu
Xuan
X
Wang
Pin
P
Tu
Xiao-Jun
XJ
Zhou
D000199:Actins / Q000378:metabolism; D000328:Adult; D018207:Angiomyolipoma / Q000378:metabolism* / Q000473:pathology; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D056657:Cathepsin K / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D058965:MART-1 Antigen / Q000378:metabolism; D008297:Male; D058950:Melanoma-Specific Antigens / Q000378:metabolism; D008875:Middle Aged; D054973:Perivascular Epithelioid Cell Neoplasms / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult; D058951:gp100 Melanoma Antigen
C541116:ACTA2 protein, human; D000199:Actins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D058965:MART-1 Antigen; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; C069203:TFE3 protein, human; D058951:gp100 Melanoma Antigen; C534130:CTSK protein, human; D056657:Cathepsin K