Keywords - parasitic fibroid - inferior epigastric artery embolization - wandering
fibroids
Introduction
Parasitic leiomyoma or “wandering fibroid” (WF) is an extremely infrequent extrauterine
benign neoplasm with unusual locations and presentations that can confound imaging
and require a histopathological diagnosis.[1] We report a case of a percutaneous biopsy proven WF. There was injury to a branch
of the inferior epigastric artery (IEA) during biopsy, resulting in a large rectus
sheath hematoma. Spontaneous rupture, trauma, and iatrogenic injury can all cause
these rare IAE bleeds, with iatrogenic injury occurring most often.[2] Urgent therapeutic embolization or surgery may be required as a life-saving measure.
Our patient underwent an IAE embolization. On follow-up imaging, there was reduction
in the size of both the hematoma and the parasitic fibroid (PF), obviating the need
for further treatment in this asymptomatic perimenopausal woman.
Case
A 48-year-old, parous, perimenopausal woman presented with lower abdominal heaviness
and swelling for 6 months that worsened on exercise and was associated with mild occasional
pain. There were no symptoms localizing to a gynecological pathology. Physical examination
revealed a well-defined, fixed, firm 9-cm mass in the left paraumbilical region under
normal overlying skin. Ultrasonography (USG) revealed an enlarged uterus with multiple
intramural fibroids. In addition, there was a well-defined heterogeneously isoechoic
9 × 8 × 7 cm solid nonspecific mass adherent to the anterior abdominal wall, with
no significant vascularity on Doppler. Although an MRI (magnetic resonance imaging)
was recommended to further characterize the lesion, contrast-enhanced computed tomography
(CECT) was done because of attendant claustrophobia.
Contrast-enhanced multidetector CT (Brilliance Big Bore, Philips, Holland, the Netherlands.)
abdomen was taken. Precontrast and postcontrast (arterial: 20 seconds, venous: 60
seconds, delayed: 5 minutes) 1-mm thin sections were acquired from the domes of the
diaphragm to just below the pubic symphysis following administration of low osmolar
nonionic contrast (Omnipaque 300, Boston, United States) at the dose of 1.5 mL/kg
and rate of 3 mL/sec.
On CT, the mass was circumscribed, oval, solid, heterogeneously enhancing (HU [Hounsfield
unit] maximum intensity projection 87), and attached to the inner surface of the left
rectus abdominis muscle of the anterior abdominal wall at the left paraumbilical region.
In addition, the uterus was enlarged and revealed multiple homogeneously enhancing
solid masses suggestive of fibroids. Although similar in appearance to uterine fibroids
inferiorly, the mass was clearly separated from the uterus by intraperitoneal fat
and intervening small bowel ([Fig. 1]). A differential diagnosis of WF, gastrointestinal stromal tumor and desmoid was
made. Since the management of these entities is different, a definite histopathological
diagnosis was sought. USG-guided core biopsy was performed using an 18 G coaxial gun
(Bard Mission Tempe, AZ). Three tissue cores were obtained and the tract sealed with
gel foam. The procedure was uneventful; however, within 30 minutes, the patient complained
of severe pain and a rapidly increasing swelling at the biopsy site. Urgent CT angiography
revealed active contrast extravasation from a tiny branch of the left inferior epigastric
artery ([Fig. 2]) within a 15 cm left rectus sheath hematoma ([Fig. 2A]). Due to significant lowering of hematocrit, an urgent embolization of the left
IEA was done using two coils (2 × 2 cm, Hilal, Cook Medical System, Bloomington, IN)
and gel foam ([Fig. 3]); stasis and no active contrast leak were taken as endpoints during embolization.
Post embolization, the patient was transfused with two units of packed red blood cells.
There was no further increase in size of the hematoma and the patient was discharged
after a few days in a hemodynamically stable condition and kept on regular follow-up.
Fig. 1 (A) Oblique sagittal CECT and (B) axial CECT showing parasitic fibroid (arrow) and uterine fibroids (solid arrow).
CECT, contrast enhanced computed tomography.
Fig. 2 (A) Sagittal CECT, (B) axial CECT, (D) oblique sagittal CECT, (C, E, and F) CT angiography MIP showing rectus sheath hematoma (arrow) and active contrast extravasation
from a branch of the inferior epigastric artery (solid arrow). CECT, contrast enhanced
computed tomography; MIP, maximum intensity projection.
Fig. 3 (A) DSA (digital subtraction angiography) selective cannulation of inferior epigastric
artery showing active contrast extravasation (arrow) and coils, (B) DSA post coil embolization showing no evidence of contrast extravasation.
Histopathology revealed benign spindle cells, positive for smooth muscle actin, and
desmin on immunohistochemistry, consistent with a benign leiomyoma ([Fig. 4]). Follow-up USG at 1 month showed partial resolution of the hematoma, as expected
([Fig. 5]). The leiomyoma also demonstrated change with marginal reduction in size and the
appearance of a few cystic spaces. Since the patient was asymptomatic and perimenopausal,
no further treatment was offered for the PF or uterine fibroids and regular follow-up
was advised.
Fig. 4 (A) Immunohistochemistry diffusely positive for desmin, (B) immunohistochemistry for Ki-67 shows 2% positivity, (C) immunohistochemistry diffusely positive for smooth muscle actin, (D) Hematoxylin and eosin stain shows fascicles of round to oval benign spindle cells
having elongated cytoplasm.
Fig. 5 Follow-up USG at 1 month showing no signal on Doppler; arrows point to wandering
fibroid. USG, ultrasonography.
Discussion
Parasitic or WFs are leiomyomas with no uterine connection or myometrial participation.[3] They can be primary where a subserosal fibroid spontaneously detaches itself and
acquires blood supply from adjacent organs or peritoneum.[4]
[5] They are commonly iatrogenic due to seedling during myomectomy or hysterectomy.[6] There are not many reported cases of parasitic leiomyoma. Most of the reported WFs
are secondary iatrogenic. Lu et al presented 6 cases of postsurgical PFs.[7] Gaspare et al concluded morcellation during hysterectomy as a risk factor in developing
parasitic leiomyomas in a retrospective study.[8] Our patient did not report prior abdominal procedures and is therefore a primary
wandering leiomyoma. The incidence of primary PFs is exceedingly rare but a few cases
have been reported.[9]
[10] Concomitant occurrence of uterine and parasitic leiomyomas has also been reported
as in our case.[11] The unusual location, uncertain origin, and extrauterine blood supply of these PFs
creates a diagnostic challenge on imaging. As in our case, a definitive histopathological
diagnosis was needed to plan effective management. However, in our case, the process
of tissue sampling resulted in a rare but potentially fatal complication of an IEA
branch bleed. A retrospective review of IEA injuries presenting to interventional
radiology departments of three university-affiliated hospitals in California, revealed
only 20 cases over a 12-year period, with a 30-day mortality rate of 30%.[12] Sobkin et al reviewed 19 cases of intervention-related IAE injury and reported the
following spectru paracentesis 40%, surgical injury 5%, percutaneous drain or biopsy
injury 15%, blunt trauma 10%, subcutaneous injection 5%, stabbing 5%, and unknown
and spontaneous 10%.[2] The IEA originates from the external iliac artery; variation in its origin is not
uncommon.[13] After origin it ascends loosely between the rectus abdominis muscle and the posterior
rectus sheath. The combination of the loose attachment of IEA with the stabilization
of its perforating branches fixed to the muscle makes the artery prone to shearing
stresses at branching sites even during strong muscular contraction or simple paracentesis.[14] Conservative approaches, such as compression of the bleed are usually not effective
because the abdomen lacks bony support and the bleeder is compressed against soft
and mobile abdominal organs. Surgery or embolization is urgently required in cases
of active bleeding because of the risk of rapid onset hypovolemic shock. We embolized
the left IEA and achieved hemostasis. Serendipitously, this intervention not only
controlled the bleeding but also partially treated the disease.
Conclusion
Parasitic leiomyomas or WFs are rare and primary spontaneous PFs are rarer still.
IEA injury is a life-threatening complication that should be kept in mind even while
performing small needle biopsies particularly in the paraumbilical region. When there
is active contrast extravasation on CECT or evidence of hemodynamic instability and
a rapidly growing hematoma, urgent embolization should be immediately performed.
