Leiomyoma of the ovary mimicking mucinous cystadenoma

Jong Chul Kima,*, Sang Lyun Namb, Kwang Sun Suhc

aDepartment of Diagnostic Radiology, Chungnam National University Hospital, 640 Daesa-dong, Jung-ku, Daejon 301-721, South KoreabDepartment of Obstetrics and Gynecology, Chungnam National University Hospital, Daejon, South Korea

cDepartment of Surgical Pathology, Chungnam National University Hospital, Daejon, South Korea

Received 20 September 1999; accepted 1 March 2000

Abstract

We present a case of ovarian leiomyoma of a 46-year-old woman with a history of a palpable lower abdominal mass. A multiloculated

multiseptated mainly cystic mass in the left adnexa on computed tomography (CT) was initially considered to be an ovarian mucinous

cystadenoma. This mass, however, was proved to be a left ovarian vascular leiomyoma on the surgical pathology. D 2000 Elsevier Science

Inc. All rights reserved.

Keywords: Ovary; Neoplasm; Ovary; Computed tomography

We recently experienced a leiomyoma of the ovary, an

extremely rare benign ovarian tumor, in a 46-year-old

woman. The lesion was initially diagnosed as a mucinous

cystadenoma of the left ovary due to the multiloculated

multiseptated mainly cystic nature of the mass. Pathology

proved that this mass was a left ovarian vascular leiomyoma

with myxoid and pseudocystic change, and suggested its

origin from smooth muscle cells in the blood vessels of the

ovary. We describe the radiologic features of this rare entity

and review the literatures of this tumor.

1. Case report

A 46-year-old woman was referred to our hospital with a

history of a sonographically detected lower abdominal mass

at a local clinic. Pelvic examination revealed a large well-

defined soft tissue mass at the left side of the uterus.

Serological tumor markers such as carbohydrate antigen

125, carcinoembryonic antigen, alpha-fetoprotein were

within normal limit. Pre-contrast computed tomography

(CT) scan revealed a large lobulated multiseptated mainly

cystic mass in the left adnexal area. This well-defined mass

abutted on the uterus, displacing the uterus to the right side

(Fig. 1A,B). Post-contrast CT images showed enhancing

walls and septa of the mass and its non-enhancing hypo-

dense cystic contents (Fig. 1C,D). On the basis of the

clinical and radiographic findings, the pre-operative diag-

nosis was a mucinous cystadenoma of the left ovary. Total

abdominal hysterectomy and bilateral salphingo±oophor-

ectomy were performed. At surgery, a large well-encapsu-

lated mainly cystic mass in the left ovary (about 15 � 10 �3 cm in size) and a small unilocular cystic mass in the right

ovary (about 2.5 � 2 cm in size) were excised. The left

ovarian mass abutted on the left side of the uterus, but it was

easily dissected from the uterus.

Gross findings of the resected specimens showed a

dumbbell-shaped mainly cystic mass in the left ovary, a

small unilocular cystic mass in the right ovary, and a

normal-appearing uterus. The cut surface of the left ovar-

ian tumor showed spongy-like consistency and multiple

foci of myxoid or pseudocystic change filled with clear

fluid (Fig. 2). On microscopic examination, this tumor was

richly vascularized by vessels of small to medium size.

The smooth muscle cells of these blood vessels were well

developed and had abundant clear cytoplasms. Proliferated

spindle-shaped cells with clear cytoplasms, which had the

same findings as vascular smooth muscle cells, were

prominent among these vessels (Fig. 3). This tumor

showed positive response to the immunochemical staining

with antibodies to vimentin, desmin, and smooth-muscle

actin. The final pathologic diagnosis of this left ovarian* Corresponding author. Tel.: +82-42-220-7835; fax: +82-42-253-0061.

E-mail address: jckim@cnuh.co.kr (J.C. Kim).

0899-7071/00/$ ± see front matter D 2000 Elsevier Science Inc. All rights reserved.

PII: S0 8 9 9 - 7 0 7 1 ( 0 0 ) 0 0 1 59 - 5

Journal of Clinical Imaging 24 (2000) 34± 37

tumor, therefore, was a vascular leiomyoma. The right

ovarian tumor was pathologically diagnosed as a theca

lutein cyst.

2. Discussion

Primary leiomyoma of the ovary is a very rare benign

ovarian tumor, and usually found incidentally on routine

pelvic examination, at surgery or autopsy [1±3]. This tumor

occurs in the women of childbearing age and of pre-

menopausal period [3±5]. Most of the patients are asympto-

matic or have only mild complaints of lower abdominal pain

[1±5]. However, acute symptoms due to torsion or necrosis

[5], hydroureteronephrosis due to the giant size of the tumor

[6], ascites [7] or hydrothorax [8] may be possible. Usually,

this tumor is unilateral, but it may be bilateral [2,9]. The

patient in our case was a 46-year-old woman who was

referred to our hospital due to a sonographically detected

lower abdominal mass at a local clinic.

The origin of the primary ovarian leiomyoma is still

somewhat debatable. Possible suggestions of its histogen-

esis are as follows: (1) mural smooth muscle in the

Fig. 1. Pre-contrast (A,B) and post-contrast (C,D) pelvic CT scans in a 46-year-old woman show a large lobulated multiseptated mainly cystic mass with

enhancing wall and septa in the left adnexal area (arrows). This mass abuts on the uterus, displacing the uterus to the right side. Pathology proved that this mass

was a vascular leiomyoma.

Fig. 2. The cut surface of the gross specimen of left ovarian tumor shows

spongy-like consistency and multiple foci of myxoid or pseudocystic

change filled with clear fluid.

J.C. Kim et al. / Journal of Clinical Imaging 24 (2000) 34±37 35

walls of hilar blood vessels [10], (2) bundles of smooth

muscle in the ovarian stromal cells [11], (3) smooth-

muscle metaplasia of hyperplastic cortical stroma, of

endometrial stromal cells in the walls of endometriotic

cysts, or of stromal cells in mucinous cystadenomas [11],

(4) smooth muscle cells in both the theca externa of the

follicles and the cortical stroma [7,10,12], (5) smooth

muscle cells normally present in the ovarian stroma [3]

especially at the attachment of the ovarian ligament [7],

etc. In our case, there was no evidence of leiomyoma-

tosis peritonealis disseminata or a uterine leiomyoma

metastasizing to the ovary. In our case, the primary

ovarian leiomyoma had abundant blood vessels of well-

developed smooth muscle cells with clear cytoplasms.

These pathologic findings may suggest the origin of an

ovarian leiomyoma from the blood vessel smooth mus-

cles in the ovary, in our case.

The ovarian leiomyoma is identical with the uterine

leiomyoma macroscopically and microscopically [5]. Most

of these tumors are solid [4±6,13], but secondary degen-

eration such as hyalinization, hemorrhage, calcification and

cyst formation may occur to some degree in this tumor, as

in the uterine leiomyomas [10]. In our case, the tumor was

a large lobulated multiseptated mainly cystic mass with

multiple foci of myxoid or pseudocystic change. Due to

the multiseptated mainly cystic nature, this lesion was

initially diagnosed as a mucinous cystadenoma of the left

ovary. Unusual cystic degeneration of a leiomyoma may

explain the atypical findings of this ovarian leiomyoma in

our case.

The imaging features of the primary ovarian leiomyo-

ma have seldom been described in the literature. Kobaya-

shi et al. [13] presented a case of this tumor as a well-

circumscribed hypointense mass both on T1- and T2-

weighted magnetic resonance images, which was sharply

demarcated from the uterus. The homogeneous low signal

intensity may be due to smooth-muscle components of the

leiomyoma, as in the classic solid uterine leiomyoma.

Due to the variable degenerative change of the ovarian

leiomyoma, pre-operative imaging diagnosis of the degen-

erated ovarian leiomyoma may often be very difficult, as

in our case. The smooth-muscle origin of the tumor may

be detected by immunochemical staining with antibodies

to vimentin, desmin, and smooth-muscle actin [14]. The

tumor in our case was positive to all these special

staining techniques.

In this paper, we present a rare case of a unilateral benign

ovarian leiomyoma in a 46-year-old woman with unusual

CT findings of a multiloculated multiseptated mainly cystic

mass, mimicking an ovarian mucinous cystadenoma. It is

considered that this mass probably originates from the

smooth muscle cells of the ovarian blood vessels.

Fig. 3. On microscopic examination, the left ovarian tumor is richly vascularized by vessels of small to medium size. The smooth muscle cells of these blood

vessels are well developed and have abundant clear cytoplasms. Proliferated spindle-shaped cells with clear cytoplasm, which have the same pathology as

vascular smooth muscle cells, are prominent among these vessels (H & E stain,�200).

J.C. Kim et al. / Journal of Clinical Imaging 24 (2000) 34±3736

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