Pelvic Schwannoma in the Right Parametrium: The First Case
(Congress code 121108)
N. Machairiotis1,*, E. Karatrasoglou2, G. Sotiropoulou2, A. Floreskou2, E. Chatzi2, P.
Zarogoulidis3, A. Stylianaki1, A. Karamani2, N. Katsikogiannis1, N. Courcoutsakis4,
C.Machairiotis 2
1
Surgery Department (NHS), University General Hospital of Alexandroupolis, Greece
2
Obstetric Gynecology Department, ``Thriasio`` General Hospital, Athens, Greece
3
Pulmonary Department, ``G. Papanikolaou`` General Hospital, Aristotle University of
Thessaloniki, Greece
4
Radiology Department, University General Hospital of Alexandroupolis, Democritus
University of Thrace, Greece
*Corresponding author
E-mail address: nikolaosmachairiotis@yahoo.com
SUMMARY
We report the case of a 58- year- old female with pelvic schwannoma, measuring
6.5 x 5.5 cm in size, in the right parametrium. Based on the rarity of this tumor, we
performed laparotomy with total abdominal hysterectomy and en-block tumor
excision. Frozen section was taken during the surgery before complete resection of
the mass, which was ambiguous. Histological examination showed a benign
neoplasm, originating from the cells of peripheral nerve sheaths, with a diagnosis of a
schwannoma. Pelvic schwannomas are very rare neoplasms that can undergo the
diagnosis or they can be misdiagnosed. Laparoscopy is a safe and efficient option for
approaching benign pelvic tumors and might offer the advantage of better
visualization of structures.
Keywords:
INTRODUCTION
Neurillemomas are benign usually encapsulated nerve sheath tumors deriving from
the Schwann cells. They constitute one of the most common types of benign
peripheral nerve sheath tumors. These tumors may be very common in cranial and
peripheral nerves, but they are rarely located in the pelvis [1, 2]. Schwannomas can
occur
sporadically
or
as
manifestations
of
genetic
conditions
such
as
neurofibromatosis 1 and 2. Pelvic schwannomas have no specific radiologic features
and are often considered to be urologic diseases or gynecologic masses [3].
MATERIAL AND METHODS
A 58-year-old Caucasian woman was admitted to gynecology out-patient
department complaining for increasing abdominal distension and sustained pain in
right bottom abdominal quadrant, independent of activities without any signs of
neurovascular deficit, the last three months. The last 48 hours the pain was located in
the right iliac fossa. Her medical and family history was unremarkable, including an
appendectomy as a child and five natural childbirths. Bimanual pelvic exam revealed
an agile cervix and a large, solid, ovoid, palpable, particularly sensitive in touch mass
in the right parametrium. Computer tomography showed a mass located in the right
ovary, corresponding to ovarian schwannoma. (Figure 1) Due to the preoperative
findings, we had to deal with a retroperitoneal tumor of unknown pathology, in a 58year-old menopausal woman. In order to ensure the optimum treatment and survival
for our patient we performed laparotomy. During the surgery frozen section was taken
which was ambiguous. Thereafter, taking under consideration the possibility of
malignancy, we performed total abdominal hysterectomy and en-block tumor excision
, with pelvic blunt dissection. A huge retroperitoneal mass was noted in the right
parametrium, measuring 6, 5 x 5.5 cm in size and showed a close proximity to the
internal iliac vein, which was ligated.(Figure 2)
RESULTS
Histological examination showed a benign neoplasm, originating from the cells of
peripheral nerve sheath, with a diagnosis of schwannoma. Immunohistochemical
studies were performed using a panel of antibodies including S-100, SMA, and CD68.
The cells were strongly positive for S100 protein and were negative for smooth
muscle actin (SMA). Immunostaining for CD68 showed numerous histiocytes in the
intermediary layer. Postoperatively, the patient recovered well and she was discharged
home on postoperative day six (6).
CONCLUSIONS
Neurillemomas are non aggressive, slowly growing solitary neoplasms with
extremely low possibility of malignant transformation or recurrence after excision [4].
Immunohistochemistry is positive for S-100, vimentin, and neuron-specific enolase,
but negative for smooth muscle actin and CD117 [4]. As a result of their slow rate of
growing and their anatomic location, pelvic schwannomas remain asymptomatic and
either they are incidentally discovered during a medical investigation for unrelated
symptoms or they are discovered as soon as they obtain large dimensions and cause a
mass effect [4,5]. More specifically, the mass effect can lead to pain in pelvic area and
lower back as well as a sense of heaviness accompanied with urinary and digestive
symptoms caused by bladder and bowel compression [5]. Their therapy is considered
to be the complete excision of the tumor either laparoscopically or with an open
abdomen surgery [6]. Taking under consideration that the vast majority of
schwannomas are benign tumors simple tumor enucleation could also be effective [4].
Laparoscopy might greatly facilitate dissection due to magnification of the anatomic
elements in the narrow pelvis [6]. It is also very interesting to refer that there are
many case reports in which the pelvic schwannomas were misdiagnosed and were
discovered during an operation that was considered to be the optimal therapy for the
initial diagnosis. Laparoscopy is a safe and efficient option for approaching benign
pelvic tumors and might offer the advantage of better visualization of structures due
to the magnification of laparoscopic view, especially in narrow anatomic spaces [6].
ACKNOWLEDGMENTS (if there are)
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Legend to the figures
FIGURE 1. Axial, enhanced CT image of the pelvis demonstrates a mass in the anatomic region of the
right ovary, corresponding to ovary’s schwannoma. The enlarged ovary is well delineated, with low
density internal, enhancing peripherally (uterus [UT], urinary bladder [BL:]).
FIGURE 2. Surgically resected lesion.
Work published in Proceedings 17th World Congress on Controversies in Obstetrics,
Gynecology & Infertility (COGI) –November 8-11, 2012, Lisbon, Portugal, edited by Z. BenRafael, Monduzzi Editoriale, Milano, Italy, 2012, pp. 177-180.
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