DOI:10.2214/AJR.04.1590
AJR 2005; 185:873-877
© American Roentgen Ray Society
Diaphragmatic Mesothelial Cysts in Children: Radiologic Findings and Percutaneous Ethanol Sclerotherapy
Devrim Akinci1,
Okan Akhan1,
Mustafa Ozmen1,
Orhan S. Ozkan1 and
Musturay Karcaaltincaba1
1 Department of Radiology, Hacettepe University School of Medicine, Sihhiye,
Ankara 06100, Turkey.
Received October 12, 2004;
accepted after revision November 15, 2004.
Address correspondence to D. Akinci
(akincid{at}yahoo.com).
Abstract
OBJECTIVE. We describe CT, MR, and sonography findings of
diaphragmatic mesothelial cysts and the results of percutaneous treatment with
ethanol. All cysts were bilobulate and showed extrahepatic location between
the right liver lobe and diaphragm.
CONCLUSION. Radiologic findings are helpful in diagnosing
diaphragmatic mesothelial cysts, which should be managed conservatively.
Percutaneous ethanol sclerotherapy should be the first choice of treatment if
necessary.
Introduction
Diaphragmatic mesothelial cysts are rare congenital lesions that are lined
with mesothelial cells. A limited number of patients, mostly adults, with
diaphragmatic mesothelial cysts that were treated by surgery has been reported
[1-5].
The diagnosis of diaphragmatic mesothelial cysts might be problematic because
of their rarity and their anatomic location.
In this retrospective study, we describe the radiologic findings, including
sonography, CT, MRI, and long-term follow-up of children who had diaphragmatic
mesothelial cysts with and without percutaneous treatment.
Materials and Methods
Records of 11 children (six girls, five boys) with 11 diaphragmatic
mesothelial cysts were retrospectively reviewed, and information about age,
lesion size, radiologic findings, treatment, and follow-up was extracted.
Patients included in the study were diagnosed between January 1998 and
February 2004 at our clinic. The mean patient age was 8 years (range, 3.5-12
years). All cysts were detected incidentally on sonographic examination in
patients with nonspecific abdominal pain. Six children underwent CT, and two
children underwent MRI. Five children were treated with diagnostic aspiration
and ethanol sclerotherapy, and the remaining six children were managed with
follow-up sonography.
Informed consent was obtained before diagnostic aspiration and
sclerotherapy from all patients. The procedure was performed on an inpatient
basis with the guidance of sonography and fluoroscopy and with the patient
under IV sedation. The patients were placed in the lateral decubital position,
and the location of the diaphragmatic mesothelial cyst was confirmed using
sonography in two planes. All patients were monitored during the procedures.
After the puncture site was selected and infiltrated with prilocaine HCl, the
initial puncture of the cyst was performed using an 18-gauge Seldinger needle
with the free-hand technique under sonographic guidance. When the needle
reached the cavity, a small amount of clear yellowish fluid was aspirated and
sent for bacteriologic, cytologic, and biochemical examinations. The
possibility of a hydatid cyst was also investigated. Then a cystogram was
obtained to evaluate the shape of the cyst and the presence of extravasation
by using Telebrix ([ioxithalamate] 350 mg I/mL, Guerbet). After the absence of
extravasation or any fistulous communication was verified, all the cyst
contents were aspirated; and 95% ethanol, which was 40% of the initial cyst
volume, was injected into the cavity via the needle. Ethanol was left in the
cavity for 10 min. Then all ethanol was aspirated and the needle was
withdrawn. Patients were called for periodic sonographic examinations 1, 3, 6,
and 12 months after the procedure, and once every year thereafter. Three
dimensions were measured, and the volume of the cyst was calculated at every
visit.
Results
Results were obtained by comparing the cyst volumes calculated at the first
and last visits. The overall mean follow-up period was 22 months (range, 3-66
months) (Table 1).
Radiologic findings showed that all the cysts were located between the
posterolateral aspect of the right liver lobe and the diaphragm (Figs.
1A,
1B,
2A,
2B,
2C,
3A, and
3B). On sonography in all
children, bilobulate cystic structures (Figs.
1A and
1B) with thin walls and thin
hyperechoic lines in the wall were identified. High-frequency sonography
showed the extrahepatic locations of the cysts and the appearance of the
"extrahepatic" sign, which is similar to the extrapleural sign
(Fig. 1B). In six children, CT
showed homogeneous, nonenhancing, well-defined cysts of water density (Figs.
2A,
2B, and
2C). MRI of two children showed
thin-walled cystic structures attached to the diaphragm wall and appearing
hypointense on T1-weighted and hyperintense on T2-weighted images (Figs.
3A and
3B). All cysts were bilobulate,
calcification of the cyst wall was observed in one cyst, and in one cyst
internal echoes were detected with a high-frequency transducer.
View larger version (147K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —Sonography findings of diaphragmatic mesothelial cyst in
7-year-old boy. Sonogram obtained with 3.5-MHz transducer shows bilobulate
cystic lesion (arrow) with thin hyperechoic line in wall.
|
|
View larger version (110K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2C —CT findings of diaphragmatic mesothelial cyst in 12-year-old
girl. After 9 months of percutaneous treatment, CT image at same level as
A shows complete resolution of diaphragmatic mesothelial cyst.
|
|
View larger version (131K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3A —MRI findings of diaphragmatic mesothelial cyst in 8-year-old
girl. T2-weighted coronal (A) and axial (B) images show
bilobulate hyperintense lesion (arrow) between diaphragm and right
lobe of liver.
|
|
View larger version (106K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3B —MRI findings of diaphragmatic mesothelial cyst in 8-year-old
girl. T2-weighted coronal (A) and axial (B) images show
bilobulate hyperintense lesion (arrow) between diaphragm and right
lobe of liver.
|
|
For the five cysts treated percutaneously, the mean volume of aspirate was
19 mL (range, 8-36 mL). Average volume reduction after sclerotherapy was 99%
during the follow-up period, which ranged from 3 to 66 months (mean, 30.4
months). Cysts disappeared completely in 80% (4/5) of children in this group 1
year after the procedure. In the fifth patient, the rate of volume reduction
was 97% 3 months after the procedure. Pain resolved in one patient and
decreased in another patient in this group. The cytologic examination was
consistent with a mesothelial cyst in one patient who showed mesothelial
cells; however, in the remaining cysts, histiocytes and macrophages were
observed. Microbiologic examinations were unremarkable, and no scolices of
hydatid cysts were detected.
Six other children with similar radiologic findings were managed
conservatively with sonographic follow-up. The mean calculated volume of the
cysts in this group was 9 mL (range, 2-23 mL). In this patient group managed
conservatively, the average volume reduction was 38.3% during the follow-up
period (range, 3-48 months; mean, 15 months). In two cysts of two children, no
change in size was observed; however, four other cysts showed a decrease in
size, with volume reduction rates of 12%, 44%, 80%, and 97%. No increase in
size was detected in any of the cysts.
Discussion
Diaphragmatic mesothelial cysts arise from coelomic remnants. Mesothelial
cysts may also be detected in organs such as the spleen, adrenal gland, ovary,
falciform ligament, vaginal process of the testicle, and mesentery
[5]. The bilobulate appearance
of diaphragmatic mesothelial cysts may be explained by the complex embryologic
development of the diaphragm
[6,
7]. Mayer et al.
[8] reported a case of a benign
two-cavity cystic lesion that had a radiologic appearance similar to that of a
diaphragmatic mesothelial cyst and was treated surgically. After histologic
examination, the lesion was thought to be either a cyst of the mesonephros or
a mesothelial cyst of the diaphragm
[8]. In that case report,
several explanations were described for the configuration of the cyst, such as
embryologic development of the diaphragm, smaller channels through the
diaphragm for nerves and blood vessels, the presence of small embryologic
defects in the diaphragm, and the cyst primarily originating from the
diaphragm [8]. However, for the
cysts in our study, the last possibility seems to be most likely because of
their anatomic location.
Because of its rarity and the difficulty of identifying its exact anatomic
location, a diaphragmatic mesothelial cyst may be misdiagnosed as an
intrahepatic simple cyst, a hydatid cyst, or another cystic lesion adjacent to
the diaphragm, such as bronchogenic cyst, teratoma, or hydatid cyst.
Estaun et al. [5] reported
the largest patient group in the literature, which included four children who
underwent surgical treatment of diaphragmatic mesothelial cysts and five
children with five cystic lesions who were managed with radiologic follow-up.
The same location and radiologic findings of these five cystic lesions led
those authors to conclude that the finding of a thin-walled cystic lesion
between the liver and the right thoracic wall in the posterolateral aspect of
the right costophrenic angle was suggestive of a diaphragmatic mesothelial
cyst [5]. Several cases have
also been reported of diaphragmatic mesothelial cysts with radiologic findings
similar to those reported in the study by Estaun et al.
[1,
2,
9]. In our study, 11 cystic
lesions could be diagnosed as diaphragmatic mesothelial cysts with the same
radiologic findings and cytologic results after excluding other, more common
causes. Additional radiologic findings were bilobulation in all cysts and
calcification in one cyst. An extrahepatic location could be identified with a
high-frequency transducer in most cases; however, coronal MR images might
rarely be necessary. To our knowledge, these radiologic findings and
percutaneous treatment of diaphragmatic mesothelial cysts with ethanol
sclerotherapy have not been reported previously in the English-language
literature.
Aspiration was considered diagnostic of diaphragmatic mesothelial cyst, and
the decision to perform ethanol sclerotherapy was made on the basis of the
imaging findings and the nature of the cyst contents. Ethanol was chosen as
the sclerosant agent because it has been commonly used for sclerosing hepatic,
renal, and splenic hydatid cysts and lymphoceles safely and successfully
[10-14].
In our study, we obtained a high rate of success with ethanol sclerotherapy of
diaphragmatic mesothelial cysts without any side effects related to ethanol.
Four (80%) of five diaphragmatic mesothelial cysts disappeared completely 1
year after the procedure, and in the other patient the rate of volume
reduction was 97% 3 months after the procedure. In this latter patient, we
believe that complete resolution of the cyst will occur by the end of the
first year. Although pain resolved in one patient and decreased in another
after percutaneous treatment, we are not convinced of a direct relation
between pain relief and percutaneous treatment.
Although diaphragmatic mesothelial cysts can be treated surgically and
percutaneously, these cysts in children can be managed appropriately with
radiologic follow-up using periodic sonographic examinations. Estaun et al.
[5] followed up five cystic
lesions consistent with diaphragmatic mesothelial cysts for 1-6 years and
observed no change in three of them, whereas the other two resolved
completely, possibly because of a breakdown or collapse of the cyst. We have
also seen no change in two of the six cysts and a significant decrease in size
in the remaining four. Because of these results, we recommend following up
these patients with periodic sonographic examinations. However, if the cyst is
symptomatic (pain, secondary infection), percutaneous ethanol sclerotherapy
should be preferred instead of surgery because of its safety and high rate of
success.
Limitations of our study are its retrospective nature and the lack of
pathologic proof in all cases. However, our study is the largest series in the
literature and can be a guide in the management of this rare benign
disorder.
In summary, we think that in cystic lesions located at the posterolateral
aspect of the right lobe of the liver, specific radiologic findings such as
bilobulation of the cysts and an extracapsular location of the liver
(extrahepatic sign), as described in this article, are pathognomonic findings
of diaphragmatic mesothelial cysts. We believe that lesions with this pattern
should be managed conservatively with periodic sonographic follow-up; if
treatment is needed, percutaneous treatment should be the first choice of
technique.
References
- Ueda H, Andoh K, Kusano T, et al. Diaphragmatic cyst with elevated
level of serum tissue polypeptide antigen. Thoracic Cardiovasc
Surg 1992; 40:195
-197[Medline]
- Sans N, Giron J, Bloom E, et al. Congenital mesothelial cyst of the
diaphragm: imaging findings— report of two cases and review of the
literature [in French]. J Radiol 1999;80
: 593-596[Medline]
- Martino G, Braccioni A, Vergine M, et al. Mesothelial cyst of the
diaphragm: report of a case and review of the literature [in Italian].
G Chir 2000; 21:290
-296[Medline]
- Mansueto G, Somma P, Amodio F, et al. Mesothelial cyst of the
diaphragm: presentation of an unusual case [in Italian]. Minerva
Chir 2000; 55:565
-567[Medline]
- Estaun JE, Alfageme AG, Banuelos JS. Radiologic appearance of
diaphragmatic mesothelial cysts. Pediatr Radiol2003; 33:855
-858[CrossRef][Medline]
- Kluth D, Keijzer R, Hertl M, et al. Embryology of congenital
diaphragmatic hernia. Semin Pediatr Surg1996; 5:224
-233[Medline]
- Schumpelick V, Steinau G, Schluper I, et al. Surgical embryology
and anatomy of the diaphragm with surgical applications. Surg Clin
North Am 2000; 80:213
-239[CrossRef][Medline]
- Mayer MP, Janzen J, Schweizer P. Intrathoracic and intraabdominal
locations of a cystic benign tumor: congenital etiology due to embryological
diaphragm development? Pediatr Surg Int2004; 19:785
-788[CrossRef][Medline]
- Bugnon PY, Soyez C, Servais B, et al. Primary non-parasitic cyst of
the diaphragm: case report and review of the literature [in French].
J Chir 1988; 125:582
-584
- Bean WJ, Rodan BA. Hepatic cysts: treatment with alcohol.
AJR 1985; 144:237
-241[Abstract/Free Full Text]
- Akinci D, Akhan O, Ozmen M, et al. Long-term results of
single-session percutaneous drainage and ethanol sclerotherapy in simple renal
cysts. Eur J Radiol 2005;54
: 298-302[CrossRef][Medline]
- Akhan O, Baykan Z, Oguzkurt L, et al. Percutaneous treatment of a
congenital splenic cyst with alcohol: a new therapeutic approach.
Eur Radiol 1997;7
: 1067-1070[CrossRef][Medline]
- Akhan O, Ozmen MN, Dincer A, et al. Liver hydatid disease:
long-term results of percutaneous treatment. Radiology1996; 198:259
-264[Abstract/Free Full Text]
- Akhan O, Cekirge S, Ozmen M, et al. Percutaneous transcatheter
ethanol sclerotherapy of postoperative pelvic lymphoceles.
Cardiovasc Intervent Radiol 1992;5
: 224-227
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Abstract
Introduction
