Pathologic evaluation of uterine leiomyoma treated
with radiofrequency ablation
Xin Luoa,⁎, Yuan Shena, Wen-Xia Songb, Pei-wen Chenb,
Xing-mei Xiea, Xiao-yu Wanga
aDepartment of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, China
bDepartment of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, China
Received 1 September 2006; received in revised form 26 March 2007; accepted 29 March 2007
Objective: To explore the mechanism by which radiofrequency ablation (RFA) treats uterine
leiomyoma by observing the features of the lesions caused by RFA to leiomyoma tissue. Methods:
Specimens from treated lesions were observed after hysterectomy was performed immediately
(acute test) or on the third day (chronic test) following treatment in 2 groups of 30 patients.
Histopathologic studies were also performed for all specimens, with untreated specimens as
controls.Results: For the acute and chronic tests, specimens from the RFA-treatedlesionsincluded
the center segment (group 1); the marginal segment (group 2); the segment 1-cm away from the
margin (group3); and the segment 2-cm away from the margin (group 4). In the acute test, group 1
showed a sharply demarcated area of coagulative necrosis that did not express estrogen receptor
2 and 3 than in the control group (Pb0.05), but ER and PRexpression in group 4, which had normal
carbonization and coagulation necrosis without ERor PRexpression. There was severe hemorrhage
and thrombosis in group 2; hyaline degeneration and tissue granulation in group 3; and mild
degeneration in group 4. The expression of ER and PR was significantly lower in groups 2, 3, and 4
than in the control group (Pb0.05). Conclusion: Radiofrequency ablation might treat uterine
leiomyomas by inducing coagulative necrosis and depressing ER and PR expression.
© 2007 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd.
All rights reserved.
Radiofrequency ablation (RFA)hasbeenusedtotreata variety
of neoplasms, including hepatocellular carcinoma, renal cell
carcinoma, hyper-functioning parathyroid adenoma, and
E-mail address: email@example.com (X. Luo).
0020-7292/$ - see front matter © 2007 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd.
All rights reserved.
available at www.sciencedirect.com
International Journal of Gynecology and Obstetrics (2007) 99, 9–13
prostatic hyperplasia, as well as hepatic, cerebral, and
retroperitoneal metastases from other primary tumors .
Yet, there are few reports using RFA in the treatment of
gynecologic disease . In this study, pathologic features and
the expression of estrogen receptor (ER) and progesterone
receptor (PR) were observed following RFA treatment in
human uterine leiomyomas to explore the mechanism by
which RFAworks, and provide guidance for clinical treatment.
2.1. Patients and tissue samples
Samples were obtained from the Departments of Obstetrics and
Gynecology of Renmin Hospital of Wuhan University and the First
AffiliatedHospitalofJinanUniversityfrom 60patients agedfrom
25 to 55 years who had multiple uterine leiomyomas (mean age,
38.6 years). Those who had other gynecologic diseases or who
had received hormonal treatment in the previous 3 months were
excluded. The study protocol was approved by the ethics
committee of the hospitals. The protocol was explained to the
patients, who gave informed consent.
Allpatients with multipleuterine leiomyomas less than5 cm in
diameter were treated under ultrasonographic guidance during
the proliferative phase with a 1.2-cm RFA electrode through the
cervical canal. Transabdominal or transvaginal hysterectomy was
in 30 patients, and on the third day (chronic test)in the remaining
30 patients. After hysterectomy, leiomyoma tissue was cut off
along the direction of the RFA electrode and specimens from the
RFA-treated lesions were obtained from the center segment
(groups 1A [acute test] and 1B [chronic test]); the marginal
segment (groups 2A and 2B); the segment 1-cm away from the
margin (groups 3A and 3B); and the segment 2-cm away from the
margin (groups 4A and 4B). The specimens forming the control
groups were obtained from untreated leiomyoma in the same
uteri. All samples were diagnosed histopathologically as benign
leiomyoma without degeneration.
Co., Wuhan, China). Its working frequency is 550±50 kHz, with
treatment. The electrode looks like a sharp knife. The 1.2-cm port
of the electrode was exposed and the other parts were insulated.
2.3. Pathology and immunohistochemistry
The specimens were fixed immediately in a 10% neutral formalin
solution for approximately 3 h, then embedded in paraffin, cut into
4-μm sections, and stained with hematoxylin and eosin for histo-
pathologic diagnosis. Immunostaining for ER and PR was performed
monoclonal antibodies (Maixin Bio Co, Fuzhou, China) on 4-μm
paraffinized in xylene and rehydrated through a graded series of
ethanol, then immersed in a 0.01 M citrate buffer (pH, 6.0) and
heated in a microwave oven for 15 min. Endogenous peroxidase
activity and non-specific antibody binding were then blocked with
0.03% hydrogen peroxide and 10% normal goat serum, respectively.
for 1 h at room temperature. Parallel control slices were
incubated with non-immunized mouse serum instead of the
specific primary antibody, and all slices were then incubated for
another 15 min with 50 μL of biotinylated goat anti-mouse
3 times in phosphate-buffered saline (PBS) for 3 min, they were
with xylene, and dehydrated through a graded series of ethanol.
microscope. Optical density (OD) was measured and analyzed
using a high-resolution image analysis system.
2.4. Statistical analysis
Data are expressed as mean±SD. Statistical analysis was
performed using analysis of variance. The statistical significance
Dunnett t test. Pb0.05 was consideredstatistically significant. All
calculations were analyzed using the SPSS software package,
version 10.0 (SPSS Inc, Chicago, IL, USA).
3.1. With the acute test
3.1.1. Gross histopathologic features
demarcated, round or elliptic area with an axial trace
concordant with the direction of the electrode. The lesion
had a reddish-brown discoloration, dry but not carbonized.
3.1.2. Microscopic histopathologic features
In group 1A, the segment was broken into bundles and the
where the RFA electrode had been. The cellular membranes
were ruptured and the cytoplasm had soiled out (Fig. 1).
In group 2A, in the area farthest from the electrode, the
smooth-muscle cells contracted and the interstitial spaces
and scaled off. In the necrotic zone, interstitial vessels were
obliterated. Vacuoles around thenuclei andthrombosis could
be observed (Figs. 2 and 3). The area had the characteristic
inter-texture or reticulate appearance of coagulative necro-
sis, and was surrounded by a hyperemic zone.
Three to 4 layers of degenerated leiomyoma cells, as well as
dilated vesselsand hyperemia, were seen ingroup 3A (Fig. 4). In
groups 3A and 4A, leiomyoma cells progressively coalesced
outside the zone. Sometimes coagulative degeneration of nerve
3.1.3. Expression ofERandPRinuterineleiomyomatissue
Optical density for ER and PR expression is shown in Table 1.
in groups 2A and 3A than in the control group (Pb0.05).
However, OD was the same in group 4A as in the control group
10X. Luo et al.
like knife-cutting, the cellular membranes were ruptured, and the
cytoplasm was overflowed.
Schwann's cells and their vacuoles formation was found.
The coagulative degeneration of nerve fibers and
cells contracted and the interstitial spaces dilated. In a partial area
there were blood vessels assembling like hemangioma. Flat
epithelial cells manifested karyopyknosis and scaled off.
In the area far from the electrode, the smooth-muscle
Edema, karyopyknosis and karyorrhexis were obvious.
Coagulative necrosis and vacuolar degeneration.
ated. Vacuoles around nuclei and thrombosis could be observed.
In the necrotic zone interstitial vessels were obliter-
phages, lymphocytes, and a few neutrophils.
There was an infiltration of monocytes, macro-
texture or reticulate appearance characteristic of coagulative
necrotic after RFA. Outside the zone three to four layers
degenerated leiomyoma cells were seen.
smooth-muscle cells, but arrayed into abnormal bunches or
inter-textured vertically and horizontally.
Uterine leiomyoma cells were similar to normal
11 Pathologic evaluation of uterine leiomyoma treated with radiofrequency ablation
3.2. With the chronic test
3.2.1. Gross histopathologic features
The lesions produced by RFA in leiomyoma tissue had a
sharply demarcated area of carbonization and coagulative
necrosis and a reddish-brown discoloration. There was an
area of severe hemorrhage and thrombosis.
3.2.2. Microscopic histopathologic features
In group 1B, cellular structure was damaged and even
obliterated near where the electrode had been, and the speci-
mens showed a sharply demarcated area of carbonization and
coagulation necrosis. Tissue was seen occasionally around the
coagulative necrotic area. Leiomyoma cells formed an amor-
phous, red-stained substance.
electrode had been, and leiomyoma cells showed vacuolar
degeneration. Edema, karyopyknosis, and karyorrhexis were
obvious. In the margin of the RFA lesion, there was an infil-
tration of monocytes, macrophages, lymphocytes, and a few
neutrophils. Macrophagic phagocytosis and fibroblasts and
capillary hyperplasia werealso observed (Figs. 6 and 7). There
were areas of severe hemorrhage and thrombosis in group 2B
and hyaline degeneration and tissue granulation in group 3B.
There was mild degeneration in group 4B.
3.2.3. Microscopic histopathologic features in the
Uterine leiomyoma cells were shuttle-shaped, similar to
normal uterine smooth-muscle cells, but were arrayed into
abnormal bunches or inter-textured vertically and horizon-
tally. Cell organelles were around the nucleus and cell
membranes had their integrity (Fig. 8).
3.2.4. Expression ofERandPRin uterineleiomyomatissue
Optical density of ER and PR expression is shown in Table 2.
There was no ER or PR expression in group 1B, and OD was
lower in groups 2B, 3B, and 4B than in the control group
Radiofrequency ablation, which can be performed with a
monopolar or bipolar approach, has received increased atten-
tion [3,4]. Current from the active electrode produces ion
agitation as it passes through tissue, which is converted into
biologic heat by means of ion friction. Because local tempera-
ture increases up to 80 °C or 100 °C, the local target tissue is
destroyed,butthesurroundingtissueisminimally damaged .
However, pathologic and biologic changes in uterine
leiomyoma treated with RFA have not been studied. In the
present study, leiomyoma tissue showed coagulative necrosis
in RFA lesions. Interstitial vessels were obliterated and there
was no expression of ERor PR. In the margin of RFA lesions, ER
and PR expression was clearly decreased in degenerating
of RFA lesions retained normal morphology without degenera-
tion or necrosis. The expression of ER and PR was still lower
than in the control group, however, demonstrating that the
result may be related to the theory that local temperature
decreases exponentially with the distance to the electrode
axis . The temperature outside the RFA lesions is not high
enough to kill leiomyoma cells, but affects the living envi-
ronment and leads to changes at the cytomolecular level.
Fibroblast hyperplasia around necrotic tissue was observed
in the chronic test group, which demonstrates that fibroplasia
is the main healing process in a RFA lesion. If complete dis-
charge or absorption of necrotic tissue does not occur, a scar
will be formed, but conversely, the absorption of a great
quantity of necrotic substances can be toxic. Therefore, while
inappropriate for large leiomyomas , RFA is fit for uterine
leiomyomas no larger than 5 cm, as it will have a high
Table 2Optical density of ER and PR expression in the chronic test(a)
Receptor No. of treated leiomyomasControl group BGroup 1BGroup 2BGroup 3BGroup 4B
Abbreviations: ER, estrogen receptor; PR, progesterone receptor.
aValues are given as mean±SD.
cPb0.05, groups 1B, 2B, and 3B vs. control group B.
Table 1 Optical density of ER and PR expression in the acute test( a)
Receptor No. of treated leiomyomasControl group AGroup 1A Group 2AGroup 3AGroup 4A
Abbreviations: ER, estrogen receptor; PR, progesterone receptor.
aValues are given as mean±SD.
cPb0.05 for groups 1A, 2A, and 3A vs. control group A.
dPN0.05, group 4A vs. control group.
12 X. Luo et al.
RFA will be improved if pharmacotherapy is used before
surgery, and originally larger leiomyomas maybe treated once
they are reduced.
Many studies have shown a significant correlation between
ER and PR concentration in local tissue and leiomyoma growth
embolization and pharmacotherapy. The latter controls leio-
myoma growthby inhibiting ERand PR activity,andleiomyoma
blocks blood from supplying the leiomyomas, leading to
leiomyoma necrosis, but can also damage myometrium and
ovary function . Radiofrequency ablation is another local
electrode inserted through the cervical canal. Not only does
this selective treatment induce a well-circumscribed irrever-
sible necrosiswitha distinct boundary,italsodepressesERand
As opposed to hysterectomy, RFA would provide an attrac-
tive,conservativenon-surgical treatmentfor uterineleiomyo-
mas no larger than 5 cm.
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13 Pathologic evaluation of uterine leiomyoma treated with radiofrequency ablation