Keywords
sarcoma - pregnancy - sepsis - preterm labor
Cancer during pregnancy is rare, with an estimated incidence of 0.07 to 0.1%.[1]
[2]
[3] An increasing incidence has been reported in several studies, likely related to
advanced maternal age.[1]
[4]
The most common cancer types during pregnancy are malignant melanoma, breast, and
cervical cancer.[1] Bone and soft tissue sarcomas have been reported in pregnancy with osteosarcoma,
liposarcoma, and Ewing's sarcoma being the most likely histological types, comprising
over 50% of the cases.[2] Fibromyxoid sarcoma in pregnancy has been reported in two studies: one in the left
atrium and ventricle and the other in the gluteus.[5]
[6]
A fibromyxoid sarcoma is a soft tissue tumor involving deep soft tissues of the extremities
and trunk, rarely located in the abdomen, and often presenting as a painless mass.
A low-grade fibromyxoid sarcoma (LGFMS) falls in the family of fibrosarcoma. First
described in 1987, it is histologically benign appearing but with a known high metastatic
potential.[7]
[8] They are commonly found in young or middle-aged men.[8]
[9]
[10]
[11] The incidence is estimated at 0.18 per million, accounting for 0.6% of all soft
tissue sarcomas.[12] However, the true incidence is unknown, as the World Health Organization characterizes
it as an “uncommon tumor.”[12]
We report a case of a symptomatic abdominal fibromyxoid sarcoma in the third trimester
of pregnancy, presenting initially with signs and symptoms of preterm labor (PTL),
and then evolving into an acute abdomen and sepsis.
Case
A 19 year-old woman, gravida 1 at 32 weeks' and 5 days' gestation presented to an
outside hospital with regular contractions and cervical effacement. For concerns for
PTL, she was given betamethasone for fetal lung maturity, nifedipine for tocolysis,
and intravenous fluids. She was then transferred to our tertiary care hospital for
further care due to fetal prematurity. Upon arrival, her cervical exam was unchanged
and her contractions had partially improved.
Her past medical history was remarkable for a known right adnexal mass measuring 9.0 × 6.4 × 7.7 cm,
documented on her 26-week ultrasound ([Fig. 1]). At that time, the etiology was unknown. The mass was described as solid with homogenous
echotexture and prominent vasculature, adjacent to the liver, suspicious for being
an accessory liver lobe. A magnetic resonance imaging (MRI) was recommended to further
elucidate the characteristics and location of the mass. However, imaging was not performed
before her presentation for PTL.
Fig. 1 Outpatient ultrasound at 26 weeks' gestation showing a solid mass, (A) approximately 10 cm, suspected to be in the right adnexa and (B) with a central vascular hyperechoic area seen with vessels tracing into mesentery.
On hospital day 3 (33 weeks' and 1-day gestation), the patient reported worsening
abdominal pain, now in her left flank. A repeat ultrasound was immediately performed
at bedside, considering the new location of her pain. The mass that was previously
described in the patient's right adnexa was now demonstrated in the left adnexa, with
stable size and characteristics. This new finding was suspicious for a torsion of
the mass, most likely resulting from the increased pressure of the growing uterus
([Fig. 2]). An MRI was performed to better characterize the mass ([Fig. 3]). Findings were consistent with ultrasound, reporting a large, soft tissue, vascular
mass now visualized in the left side of the abdomen. There was also a suspicion for
an abscess collection adjacent to the mass.
Fig. 2 Inpatient ultrasound showing a previously identified right adnexal mass now on the
left, with stable size and characteristics, including prominent vascularity.
Fig. 3 Inpatient magnetic resonance imaging (MRI) without contrast showing left-sided 12-cm
abdominal mass.
Her condition worsened as she developed a new onset of fever with a maximum temperature
of 103°F (39.4°C), tachycardia to the 120s, and hypotension (blood pressure in the
90s/50s). She had severe lower abdominal tenderness on the left lower abdominal quadrant
with guarding. Findings were suggestive of an acute abdomen and sepsis, and the patient
was taken to the operating room along with general surgery and started on broad-spectrum
antibiotics due to concerns of intraabdominal infection with an unknown source.
A cesarean was followed by an exploratory laparotomy, via a low midline vertical skin
incision and low transverse hysterotomy. During the cesarean the patient had significant
uterine atony requiring several uterotonics, followed by blood transfusion of 2 units.
Purulent peritoneal fluid from the left lower quadrant was sent for cytology. The
mass was continuous with the peritoneum and resected along with a portion of the small
bowel due to adhesions ([Figs. 4] and [5]). A small bowel side-to-side anastomosis was completed.
Fig. 4 Intraoperative assessment of the mass, seen adhered to the small bowel.
Fig. 5 The intraoperative mass was resected with a portion of small bowel attached (A anterior and B posterior, showing orifice draining pus).
The patient was discharged on postoperative day 7—afebrile, tolerating regular diet,
and with adequate pain control. The intraoperative fluid sample grew pan-sensitive
Klebsiella pneumoniae for which she completed the antibiotics course. The infant did well and was discharged
home on day 11 of life.
Final pathology of the mass revealed a low-grade fibromyxoid spindle cell neoplasm.
Pathology reported the tumor to be composed of spindle cells arranged in short fascicles
in a fibromyxoid matrix. The cells had pale eosinophilic cytoplasm and oval nuclei
with coarse speckled chromatin ([Fig. 6]). The mitotic rate was less than 1 mitosis per 10 high-power fields. Proximal, distal,
and radial margins appeared clear of neoplasm, but the tumor extended to the visceral
peritoneum.
Fig. 6 Hematoxylin and eosin stained at 40× (A) and 100× (B), smooth muscle actin immunostain (C), and β catenin immunostain (D) showing the characteristics of the low-grade fibromyxoid spindle cell neoplasm.
Patient was referred to the oncology service and is currently under surveillance every
6 months with imaging, to assess for risk of recurrence. To date, patient has been
stable with no reported recurrence.
Discussion
Fibromyxoid sarcomas are soft tissue tumors involving deep soft tissues rarely found
in the abdomen as described in the nonpregnant population.[13] They affect patients of all ages, with peak incidence in young adults, with an equal
male-to-female ratio.[13]
[14] In a large series of pregnancies complicated by bone and soft tissue tumors, the
most common affected locations were the pelvis, abdomen, and extremities.[2] Very few case reports have been published about intra-abdominal fibromyxoid sarcoma.[9]
[10]
[15]
LGFMS has a histologically benign appearance; however, it is a malignant and late
metastasizing tumor.[13] Rates of recurrence are difficult to assess due to low incidence of these tumors
and difficult follow-up with long intervals from primary diagnosis to recurrence.[7] In a series of 33 LGFMS cases, patients with negative margins at diagnosis had better
survival.[7] Smaller tumors (<3.5 cm) were associated with decreased recurrence. Local recurrence
was demonstrated in 63% of the cases and metastasis was reported in 46% of cases with
site of metastasis in lung, pleura, and chest wall.
The management of pregnancies complicated by cancer remains challenging due to late
diagnosis in most of the cases resulting from overlap between pregnancy physiological
changes and cancer symptoms as well as delayed treatment due to potential maternal
and fetal risks.[1]
[2]
The best treatment approach of sarcomas in pregnancy remains debatable. Overall, pregnant
women are candidates for standard surgical management in pregnancy.[2] The decision for chemotherapy or radiation should be evaluated on an individual
basis.[2] Multidisciplinary approach between obstetricians, oncologists, and neonatologists
is essential to improve outcomes.[2] Due to its low nuclear grade and infrequent mitotic activity, LGFMSs are not sensitive
to chemotherapy or radiation.[13] Surgical excision with clear resection margins remains the first-line treatment
option.[13]
[14]
In the largest systematic review of the literature currently available on 40 pregnancies
complicated by sarcomas (including uterine, vaginal, vulvar, and retroperitoneal),
the mean age of patients was 27.8 ± 7.0, onset of symptoms was described in the third
trimester in 50% of the cases, 42% did not have initial suspicion for malignancy,
and 82% had live-born infants with premature deliveries in almost 50% of the cases.[3] In all cases, the primary tumor was treated with excision, five cases used neoadjuvant
radiation, and in one case, chemotherapy was used.[7] Our case is the first one in the literature to report an abdominal fibromyxoid sarcoma
in pregnancy. As evidenced by intraoperative finding, the sarcoma was thought to have
torsed to include a part of the small bowel causing an intra-abdominal infection leading
to sepsis and PTL. Additionally, a common gut flora, Klebsiella pneumonia, was cultured from the intraabdominal fluid collection, which is indicative of a
possible bowel perforation.[16] This case not only demonstrates that our patient's characteristics and outcomes
are similar to what has been previously reported[3] but also highlights the importance of keeping a broad differential when evaluating
PTL, including causes of acute abdomen and sepsis as well as understanding how the
anatomical changes in pregnancy need to be taken into consideration when making diagnosis
of a surgical abdomen such as in cases of appendicitis or this specific case. This
case also highlights the need for a multidisciplinary approach to safely evaluate
and manage a rare presentation of sepsis and PTL in pregnancy.
