REV ARGENT COLOPROCT | 2024 | VOL. 35, N
o
2 CASE REPORT
PERINEAL LEIOMYOSARCOMA: AVOID SEQUELAE OR PREVENT RECURRENCES ? Nielsen D.. et al..
Perineal leiomyosarcoma: Avoid consequences or prevent recur-
rences?
Debra Nielsen, Cristian Nicolás Lucas, Pablo Catalano
Sanatorio Franchin, Ciudad de Buenos Aires. Argentina
ABSTRACT
Soft tissue leiomyosarcomas (LMS) are malignant tumors that,
when located in the perineum, pose additional difficulties because
in this region multiple relevant anatomical elements coexist in
extreme proximity. It is known that local recurrence and distant
metastasis rates reach 37 and 62%, respectively, so in selected
cases aggressive surgical approaches with wide margins and
adjuvant radiochemotherapy are usually recommended to reduce
these percentages. The case of a 42-year-old woman with a right
perineal tumor of 9 years of evolution, painful due to increase in
size, is presented. On physical examination, she had a mobile
lesion not attached to deep planes. Computed tomography with
intravenous contrast shows tumor with clear edges, in contact with
the lateral wall of the rectum. A marginal resection of the tumor was
performed, respecting the integrity of its capsule. The pathological
study reported low-grade LMS. After 18 months of follow-up, she
has no recurrence. Conservative resections may be appropriate in
selected low-risk patients with localized disease. More evidence is
needed to confirm these findings.
Keywords: perianal leiomyosarcoma, perineal sarcoma, perineal
tumor
INTRODUCTION
Soft tissue leiomyosarcomas (LMS) are malignant tumors of
muscular origin, which represent 3% of sarcomas and 0.04%
of all neoplasms. Due to their low incidence, for their man-
agement and staging they are grouped together with a set of
other malignant entities of mesenchymal origin. Its progno-
sis worsens as its location deepens, reaching local and
distant recurrence rates of up to 37 and 62%, respectively.
1
The age of presentation is between the 4th and 5th decades
of life. They are usually single, voluminous, painless, slow-
growing tumors reminiscent of lipomas but with a harder
consistency. Occasionally, they may be associated with
itching or sweating.
Given its low incidence, there is no specific TNM for LMS,
so the AJCC classification of sarcomas is used.
CASE
A 42-year-old woman consults for a 9-year-old soft tissue
tumor in the right ischiorectal fossa. She reports slow and
sustained growth, and recent appearance of pain and tenes-
mus due to increased volume. She has no history of perineal
surgery or trauma. The physical examination revealed a
hard, mobile tumor, not adhered to deep planes, measuring 7
cm, which displaces the anal orifice and the sphincter appa-
ratus without compromising it macroscopically, and which
causes a marked asymmetry in the perineum. (Fig. 1).
Figure 1. In the lithotomy position, the tumor is observed in the
right ischiorectal fossa.
Computed tomography with intravenous contrast revealed a
solid, homogeneous, hyperdense mass, measuring 8 cm, in
the right ischiorectal fossa, in contact with the lateral rectal
wall. It has defined edges, enhanced with intravenous con-
trast. No enlarged lymph nodes are evident and both the
liver and lungs are free of pathological images (Fig. 2).
The patient is evaluated by the multi-disciplinary tumor
board, considering two alternatives: radical surgery, includ-
ing abdominoperineal resection, or marginal resection and
re-evaluation with the result of the biopsy.
Given that the patient categorically rejects a resection that
could cause serious local consequences or compromise her
continence, it was jointly decided to perform a marginal
resection.
In the lithotomy position, an incision is made over the
tumor, which contacts the left lateral wall of the rectum
without invading it (Fig. 3). Enucleation is performed
respecting the pseudocapsule.
The patient progressed favorably and was discharged after
24 hours. The pathological anatomy reported a low-grade
LMS measuring 9 x 8 x 8 cm. Mitotic count up to 5 fig-
ures/mm
2
, with a cell differentiation score of 1 and Ki67
7%.
As it was a Grade I tumor, it was decided to reserve adju-
vant treatment only in case of recurrence. The patient is
currently under strict follow-up with MRI of the abdomen
and pelvis and thoracic CT quarterly for the first 3 years, in
accordance with current recommendations for sarcomas.
2
There is no evidence of local or distant recurrence after 18
months of follow-up.
The authors declare no conflict of interest.
Received: June 9, 2023. Accepted: May 2, 2024
Debra Nielsen https://orcid.org/0000-00001-8697-5690 Cristian Nicolás Lucas https://orcid.org/0000-0002-4874-3386 Pablo Catalano https://orcid.org/0000-0001-7582-2162
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2 CASE REPORT
PERINEAL LEIOMYOSARCOMA: AVOID SEQUELAE OR PREVENT RECURRENCES ? Nielsen D.. et al..
Figure 2. Computed tomography with intravenous contrast showing
the location of the tumor in close contact with the rectal wall and the
sphincter complex.
Figure 3. Enucleation of the tumor with its pseudocapsule intact.
DISCUSSION
Given the low incidence of perineal LMS, diagnostic suspi-
cion is usually low, often presenting as an unsuspected
result in the late pathological study of the tumor. This results
in a worse prognosis due to delayed treatment.
3
According to the initial publications on LMS of the extremi-
ties,
4,5
treatment was based on an aggressive surgical ap-
proach, with wide resections and minimum free margins of
4 cm.
However, even in patients with R0 resections, local recur-
rence is evident in up to 37%,
6
which encouraged the study
of poor prognostic factors independent of the treatment
offered.
According to the ESMO-EURACAN-GENTURIS Clinical
Practice Guidelines, updated in 2021,
2
prognostic factors in
soft tissue and visceral sarcomas include the size of the
lesion, its location, the mitotic index and the presence of
necrosis and vascular invasion. On the other hand, the
Federation Nationale des Centers de Lutte Contre le Cancer
(FNCLCC) classifies soft tissue LMS into three degrees of
malignancies according to a score based on cellular differen-
tiation (good, moderate or poor), necrosis (absent, minor or
major: >50%) and mitotic count (<10, 10 to 20, >20 fig-
ures/mm
2
).
7
With a maximum score of 8 points, Grade I
adds up to 3 and has 5-year survival rates >95%. Grade II
and III add 4 or more points and have a formal indication for
multimodal treatment, because local relapse rates rise up to
60%.
8
In the current treatment of this pathology, wide surgical
resections continue to prevail as the standard treatment,
guaranteeing lesion-free margins ideally greater than 10
mm.
9
The role of radiotherapy, although still debated, may be
especially relevant when surgical margins are involved or
threatened after surgery and re-resection is not possible,
particularly in high-grade lesions. Likewise, radiotherapy is
useful in the palliative local control of cases with advanced
disease and presence of metastases.
6
Chemotherapy constitutes the fundamental basis of the
treatment of metastatic disease. Although it is not curative, it
can delay its progression.
10
The most commonly used drugs
include doxorubicin, ifosfamide, gemcitabine, taxotere,
dacarbazine and trabectedin, in combination regimens.
In both cited guidelines,
2,7
marginal resection as the only
treatment, is offered only in carefully selected cases. This is
an individualized decision in patients with Grade I tumors
with complete pseudocapsule and without distant disease,
who can adapt to a strict follow-up in high complexity
centers for at least 5 years.
CONCLUSION
Perineal soft tissue LMS are a rare entity, so there is little
scientific evidence to indicate the best approach in the
treatment of this disease. Although wide resections are the
most widely accepted surgery for the treatment of all sarco-
mas, the perineal location could imply the need for resection
of the sphincter, lower rectum and urinary tract, with the
need for permanent ostomy, multiple functional impairments
and severe impact on the quality of life. The correct selec-
tion of patients allows opting for more conservative surgery,
with less morbidity but similar oncological safety.
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