Endometrioma With Calcification Simulating a Dermoid - Journal of ...

Endometrioma With Calcification Simulating a Dermoid
whereas only 6% of nonendometriomas did so.
Their data indicate that a mass with low-level
internal echoes, hyperechoic wall foci, and no
neoplastic features is 32 times more likely to be
an endometrioma than another adnexal mass.
Generally endometriomas are not thought to
contain fluid-fluid levels. However, endometriomas
contain blood of different ages, which
sometimes can appear as a fluid-fluid level on
imaging studies. The observation missed on the
initial sonographic examination was that the
dependent layer in the fluid-fluid level was
echogenic, which was due to the presence of
echogenic blood. If this echogenic layer was fat, it
would have been in the supernatant location; that
is, the mass would show supernatant hyperechoic
and dependent hypoechoic layers. However, this
mass showed supernatant hypoechoic and
dependent hyperechoic layers, which have been
observed in endometriomas. 6
Certain sonographic features (focal acoustic
impedance, regional bright echoes, and hyperechoic
lines and dots) are predictive of cystic teratomas.
7 Although the hyperechoic shadowing
focus is very predictive of a teratoma, not all
hyperechoic shadowing areas are due to calcifications.
Furthermore, although a calcification can
certainly occur in a teratoma, a calcification by
itself is not pathognomonic of a teratoma. A teratoma
can contain a nonshadowing echogenic
focus or a shadowing calcification. The positive
predictive value for individual sonographic features
associated with dermoid masses is 80% for a
shadowing echogenic focus and 20% for a fluidfluid
level. 6 On sonography, the dermoid plugs
are seen as an echogenic mass, often associated
with distal acoustic shadowing. 8 Although hyperechoic
foci are described in the wall of the
endometriomas, a discrete shadowing focus similar
to that seen in a dermoid cyst has not been
reported in the literature.
Histopathologic findings of the resected
endometrioma revealed extensive fresh and old
blood with hemosiderin-laden macrophages. A
large, marblelike calcification was identified.
The most commonly promulgated hypothesis
is that calcification of degenerated hyalinized
cells leads to the eventual formation of psammoma
bodies in any organ. 9 In most situations, the
concentration of calcium and phosphate in the
extracellular fluid cannot initiate hydroxyapatite
crystal formation, but once a crystal nidus is
formed, it can sustain development of large calcified
masses. The nidus within an endometrioma
can originate from degenerating cells, from
ruptured cell membrane material, or from calcium-rich
intracellular organelles. All these possibilities
are plausible.
Necrosis appears to be one of the common
denominators for calcification and psammoma
body formation. In endometriosis, there is some
necrosis of the cells as the hormonally active
glandular tissue is subjected to the menstrual
cycle. 10,11 Fine-needle aspiration cytologic examination
of endometriomas is well documented.
Aspirates of endometriomas are generally moderately
cellular, containing endometrial stroma
and glandular components.
The ovarian tumors associated with psammoma
bodies include adenofibromas, cystadenocarcinomas,
and papillary adenocarcinomas.
Psammoma bodies in an epithelial tumor are not
diagnostic of a malignancy. 12 Psammoma bodies
are seen in both benign and malignant lesions.
In conclusion, although a focal calcification is
pathognomonic of a dermoid, it may be occasionally
seen in endometriomas. Awareness of
this finding will include endometrioma in the
differential diagnosis of a cystic adnexal mass
containing a calcification. Also, the fluid-fluid
level seen in the adnexal mass on sonography is
strongly suggestive but not pathognomonic of
dermoids and may be seen in endometriomas
and other cystic tumors. These lesions can then
be further characterized with MRI, which has the
capability of differentiating blood products from
fat, thus allowing a definitive diagnosis.
References
1. Mais V, Guerriero S, Ajossa S, Angiolucci M, Paoletti AM,
Melis GB. The efficiency of transvaginal ultrasonography in
the diagnosis of endometrioma. Fertil Steril 1993;
60:776–780.
2. Patel MD, Feldstein VA, Chen DC, Lipson SD, Filly RA.
Endometriomas: diagnostic performance of US. Radiology
1999; 210:739–745.
3. Fried AM, Rhodes RA, Morehouse IR. Endometrioma: analysis
and sonographic classification of 51 documented cases.
South Med J 1993; 86:297–301.
4. Jain KA. Prospective evaluation of adnexal masses with
endovaginal gray-scale and duplex and color Doppler US:
correlation with pathologic findings. Radiology 1994;
191:63–67.
5. Volpi E, De Grandis T, Zuccaro G, La Vista A, Sismondi P.
Role of transvaginal sonography in the detection of
endometriomas. J Clin Ultrasound 1995; 23:163–167.
1240 J Ultrasound Med 2006; 25:1237–1241