Open Journal of Obstetrics and Gynecology, 2011, 1, 217-220
doi:10.4236/ojog.2011.14042 Published Online December 2011 (http://www.SciRP.org/journal/ojog/ OJOG ).
Published Online December 2011 in SciRes. http://www.scirp.org/journal/OJOG
The perplexing entity of rudimentary uterine horn
Ria Malik, A. G. Radhika, Alpana Singh, Gita Radhakrishnan, Rachna Aggarwal
Department of Obs and Gynae, University College of Medical Sciences (UCMS) and GTB Hospital, Delhi, India.
Received 15 September 2011; revised 19 October 2011; accepted 5 November 2011.
ABSTRACT
A rudimentary uterine horn may be responsible for
intriguing presentations in different stages of life. The-
se presentations often masquerade commoner gynae-
cologic disorders resulting in diagnostic and manage-
ment challenges for the treating clinicians. Whereas
many of these anomalies may be discovered during
the investigative workup for cryptomenorrhoea, dys-
menorrhoea and infertility, due to lack of symptoms
especially in a parous woman, a large proportion re-
mains undiagnosed. We report here, two interesting
presen- tations of this benign entity resulting in sig-
nificant morbidity. The first case report describes
late activation of a rudimentary horn presenting as
chronic pelvic pain. The second patient presented
with a failed second trimester induction of labor
(abortion) for fetal demise. Her examination and in-
vestigations suggested an abdominal pregnancy, yet,
on laparotomy, a 15 week pregnancy within an acces-
sory uterine horn was discovered.
Keywords: Rudimentary Uterine Horn; Chronic Pelvic
Pain; Laproscopic Management; Abdominal Pregnancy;
Ruptured Rudimentary Horn
1. INTRODUCTION
Mullerian duct malformations repr esent a wide spectrum
of anomalies, resulting from varying degrees of defects
in the development and fusion of the mesonephric ducts.
We present here, two unusual presentations of unicorn-
nuate uterus wi t h ru di mentary horn.
2. CASE I
Ms S, 37 yrs, P3L3 presented in our out patient clinic
with complaints of dull achin g lower abdominal pain sin-
ce past 4 yrs. Recent history of dysmenorrhoea was no-
ted. Her many visits to different gynecologists and sur-
geons did not prove fruitful. No symptoms suggestive of
pelvic infection, bladder or bowel pathology were noted.
Her first two children were term normal vaginal delive-
ries, third was a caesarian section with tubal ligation for
placenta previa, five years ago. Her postoperative period
was uneventful and she was not informed of anything
unusual at discharge; no papers relevant to the surgery
were available when she presented to us. Her menstrual
cycles had been regular and no period of amenorrhea
was reported. General physical examination was unre-
markable except for a pfannensteil caesarean scar. Spe-
culum examination revealed normal cervix and vagina.
On vaginal examination, uterus anteverted multiparous
size. There was a 4 cm × 4 cm size, mobile, smooth and
slightly tender right adnexal mass. Transvaginal sono-
gramphy showed a well circumscribed thick walled
complex mass 4 × 3 cms in right adnexa with partially
echogenic contents. Left ovary was normal. Provisional
diagnosis of chronic pelvic inflammatory disease (PID)
or possibly an endometrioma was considered. Her persis-
tent symptoms despite treatment for PID mandated
laparoscopy. At laparoscopy, the right ovary was found
normal, the ligated right fallopian tube was seen arising
from a 3 c m × 3 cm smooth surfaced thick muscular mass
attached at the right uterine cornu. The right round liga-
ment was attached to this mass confirming it to be rudi-
mentary uterine horn. 4 ml of dark altered blood was
aspirated from this mass. The other uterine half was
normal in shape size and contour, left ovary and tube
(ligated) were normal (Figure 1).
3. CASE II
25 yr old Ms. B, primigravida was referred by a practi-
tioner for hysterotomy following failed attempt at se-
cond trimester termination of a nonviable pregnancy.
She was married for 10 years and was under treatment
for infertility since 7 years. The hysterosalpingogram arou-
sed the suspicion of a bicornuate uterus though it was
not confirmed laparoscopically. The present pregnancy
was a natural conception. Ultrasonography done in the
first trimester did not show anything abnormal. At 5
months into pregnancy, she had an episode of vaginal
bleeding, when ultrasound revealed fetal demise. Termi-
nation of pregnancy using vaginal and systemic prosta-
glandins was unsuccessfully attempted by the practitio-
ner, and patient referred to our centre for hysterotomy.

R. Malik et al. / Open Journal of Obstetrics and Gynecology 1 (2011) 217-220 218
Figure 1. Laproscopic view of rudimentary horn with normal
uterus, causing CPP in Case 1Laparoscopic hemi hysterectomy
of the rudimentary horn was performed (Figure 2). The patient
had an uneventful post operative period. Histopathological ex-
amination confirmed uterine tissue. The patient remains sy-
mptom free till date.
Figure 2. Altered blood which was aspirated from the horn and
the resected rudimentary horn.
On examination, her vitals were stable; there was a pal-
pable abdominal mass arising form pelvis corresponding
to 14 wks gravid uterus. Speculum examination demon-
strated a single centrally placed cervix. On vaginal exa-
mination, cervix uneffaced, uterus normal sized deviated
to left side. A mobile nontender cystic mass 8 cm × 8 cm
was felt on the right side. Ultrasound revealed a normal
sized empty uterus having endometrial thickness of 5
mm. A gestational sac with a dead fetus of 15 wks was
noted to the right and anterior to uterus (Figure 3).
Both ovaries were normal. Provisional diagnosis of se-
condary abdominal pregnancy was considered. MRI re-
ported similar findings (Figure 4), further confirming the
diagnosis of secondary abdominal pregnancy.
Figure 3. Ultrasound of Case 2 showing single fetus in a mus-
cular structure outside the normal uterus.
Figure 4. MRI showing findings suggestive of abdominal
pregnancy.
An exploratory laparotomy was performed. At lapro-
tomy, the uterus, left tube and ovar y were normal. There
was a right sided 8 cm × 8 cm muscular structure, at-
tached to uterus by a fibrous band; the right tube was
seen arising from this mass. Round ligament of right side
was seen arising lateral to this mass, thereby confirming
it to be a uterine horn. The right ovary was normal. This
rudimentary horn was excised with the fetus in situ. Cut
section of the mass showed a muscular wall with a dead
fetus inside. Post operative recovery of the patient was
uneventful. Definitive con firmation of uterine tissue was
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done by histo p at hology.
4. DISCUSSION
The exact incidence of mullerian abnormalities is not
known because of normal fertility outcome in majority
of these women. Estimates range from 1% - 3.5%, with
higher percentage prevalence in infertile women (6.3%)
[1]. Unicornuate uterus is categorized in Class II of the
American Fertility Society classification (1988) of mul-
lerian anomalies. It accounts for 2.4% - 13% of all mul-
lerian anomalies [2,3]. Since fertility outcome is not
usually affected, the clinical presentation may be highly
variable; ranging from an apparently trivial dysmenor-
rhoea in an adolescent girl to intractable vague pelvic
pain in a parous woman. The presence of normal men-
strual flow further blankets the possibility of a uterine
anomaly. As high as 78% of rudimentary horns have
been known to presen t in the third decade of life o r later,
most often as acute emergencies resulting from rupture
of horn pregnancy [4]. Unless specifically sought, ultra-
sound done for other gynecologic disorders often fails to
pick up such malformations. In a review of 266 rudi-
mentary horn presen tations, sensitivity of two dimensio-
nal USG as a diagnostic tool was shown to be only 26%
[4]. A novel method of prerup ture diag nosis of rudiment-
tary horn pregnancy has been suggested by Buntugu et
al. The method involves placement of a Foley’s catheter
into uterine cavity with bulb inflated. An abdominal ul-
trasound with full bladder is then performed. Although
the method is claimed to offer better sensitivity over
conventional sonography, more studies are needed be-
fore it can be recommended for routine use [5]. Recent
studies by Ghi et al, found 3-dimensional transvaginal
ultrasonography to be extremely accurate in the diagno-
sis of uterine anomalies. They found a concordance be-
tween endoscopy and 3D ultrasound in 52 of 54 cases [6].
However, MRI where available, still remains the gold
standard for confirmation of mullerian anomalies.
Chronic pelvic pain has been reported in 15% - 20%
of women aged 18 yrs - 50 yrs [7,8,9] and is an indica-
tion for at least 40% of all gynecologic laparoscopies
[10]. Whereas 8.5% of adolescents undergoing laparo-
scopy for pelvic pain have some form of uterine mal-
formation [11], mullerian anomalies as a cause for
chronic pelvic pain in a parous woman is rarely reported
[12].
We were intrigued by the late p resentation and missed
diagnosis of existence of this horn in our patient who
had had a normal reproductive outcome including a ce-
sarean section. The patient had denied any prior history
of pelvic pain or dysmenorrhoea, suggesting recent acti-
vation of disease. Possible explanation for the late onset
of symptoms in this case could be tubal ligation inciting
accumulation of menstrual blood in the horn, thereby
precipitating pelvic pain. This phenomenon has also been
reported by Fugimoto et al [13]. Rudimentary horn as a
cause of pelvic mass and pain has even been reported
after vaginal hysterectomy in a 41 yr old lady [14]. The-
se reports suggest possible role of various “triggers”
which cause activation and presentation of such rudi-
mentary horns late in reproductive life. The diagnosis
had been completely missed at cesarean section probably
due to the small size of the horn as compared to the term
gravid uterus and the obvious altered anatomic relations.
The commonly accepted treatment for this entity is
excision through laparotomy or laparoscopy. Other treat-
ment options include endometrial ablation of accessory
horn through hysteroscopic approach; with reported sy-
mptom free period of up to 3 yrs [15]. Hysteroscopic
drainage of hematometra in a noncommunicating acces-
sory horn by using electrocautery to create a communi-
cation between the horns has al so been descr i bed [16].
Pregnancy in rudimentary horn has been noted once in
1225 ectopic pregnancies [17] and once in 76000 total
pregnancies [18]. The most significant threat is the risk
of rupture; which is estimated to be about 50% and most
commonly occurs in second trimester [19]. Various signs
and symptoms pointing to presence of a uterine anomaly
have been described, including past history of dysme-
norrhoea, pregnancy along with a freely mobile tumor,
passage of a decidual cast, absent tenderness on exami-
nation (unlike a tubal ectopic) [20] etc. But still, only a
very small percentage of these rudimentary horn preg-
nancies are accurately diagnosed pre-operatively. While
excision of this “ectopic” pregnancy along with the ac-
cessory horn remains the most common treatment mo-
dality, combined medical and surgical treatment has also
been tried. This involves fetal intracardiac potassium
chloride and intraplacental methotrexate, followed 6 wks
later by laparoscopic resection of the horn [19]. Such
combined medical, surgical modality has the advantage
of reducing the vascularity, thereby decreasing operative
blood loss [19]. Additional studies are needed before the-
se treatment modalities are widely accepted.
5. RECOMMENDATIONS
The authors would like to recommend that clinicians be
sensitive to the presence of mullerian anomalies in pa-
tients with otherwise normal gynecologic and reproduce-
tive histories. The diagnosis should be considered in
unusual presentations of pelvic pain or early pregnancy.
Although relatively insensitive, the routine ultrasound
may prove helpful if clinicians bear in mind these dif-
ferential diagnoses. Emergency staff should be alert to
the possibility of such malformations in patients pre-
senting with acute abdomen, suspected ruptured ectopic
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R. Malik et al. / Open Journal of Obstetrics and Gynecology 1 (2011) 217-220 220
or even failed induction with adequate doses of prosta-
glandins. A thorough inspection of the pelvis should be
performed at the time of any operative procedure. Pro-
phylactic resection of a noncommunicating uterine horn
should be considered in patients with incidental disco-
very on laprotomy to prevent endometriosis and possible
future horn pre gnancy.
[10] Howard, F.M. (1993) The role of laparoscopy in chronic
pelvic pain: Promise and pitfalls. Obstetrical and Gyne-
cological Survey, 48, 357-387.
doi:10.1097/00006254-199306000-00001
[11] Vercellini, P., Fedele, L., Arcaini, L., et al. (1989)
Laparoscopy in the diagnosis of chronic pelvic pain in
adolescent women. Journal of Reproductive Medicine, 34,
827.
[12] Howard, F.M. (2003) The role of laparoscopy in chronic
pelvic pain patient. Clinical Obstetrics and Gynecology,
46, 749-766. doi:10.1097/00003081-200312000-00004
6. CONFLICT OF INTEREST
We declare that we have no conflict of interests. [13] Fugimoto, V.Y., Klein, N.A. and Miller, P.B. (1998) Late
onset hematome tra and he matosalpi nx in a woman wit h a
noncommunicating uterine horn: A case report. Journal
of Reproductive Medicine, 43, 465-467.
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