Discussion
This is the first case-report of a woman with APSN, who carried two
pregnancies after this diagnosis. A hysterectomy after completion of her
family, revealed on histological examination a persistent APSN that was
prior clinically and radiologically undetectable. The impossibility to
detect the lesion on scans and hysteroscopy is due to its linear
appearance and small width.
Five articles have reported cases of APSN, describing a total of 26
patients ², ⁵-⁸. However, no
subsequent pregnancies have been reported before. At the moment of
diagnosis, maternal age ranged between 31 and 43 years old. The
presentation of symptoms in our case is similar to that of other cases
described in literature. Most patients presented with complaints of
irregular vaginal bleeding (n=18), two patients presented with a pelvic
mass and pelvic pain, the other cases (n=6) were incidental findings of
APSN after curettage or hysterectomy. In four patients, ultrasound
abnormalities were described consisting of a cystic mass in utero. In
the remaining 22 patients, results of imaging were not described. All
hCG-levels at the moment of diagnosis of APSN or GTN were low or below
detection threshold, as in our case.
Four of the 26 patients (15%) with APSN were diagnosed with GTN
synchronously or during follow-up ²,⁵. Two patients
had a mixed tumor consisting of APSN and PSTT or APSN, PSTT and ETT. One
patient developed ETT six months after APSN diagnosis, another patient
developed PSTT 16 months after APSN diagnosis. All patients diagnosed
with GTN were treated only with hysterectomy, no additional chemotherapy
was needed.
In contrast to our case, seven patients opted for immediate treatment
after diagnosis of APSN and underwent a hysterectomy. Four patients
underwent surgery for other reasons than APSN and unexpected diagnosis
of APSN was based on tissue from the hysterectomy, they did not receive
other additional treatment. Two patients were treated with a wedge
resection, in one patient no follow-up was described and the other
patient was followed for 12 months without displaying complications
⁶,⁸. Nine patients were diagnosed with APSN based on
material retrieved during suction curettage and did not receive
additional surgical removal of any kind. Of these patients, four did not
display signs of recurrence during follow-up (length of follow-up not
described), the other five patients were lost to follow-up. In none of
these patients a subsequent pregnancy was reported.
To the best of our knowledge, no literature exists on patients with APSN
and subsequent pregnancies. No previous literature has been published on
fertility sparing (surgical) treatment in APSN and in case of ETT or
PSTT fertility sparing treatment is uncommon⁹. This is the first
case-report of a woman still wishing to conceive and in whom an
expectant management was installed rather than performing a hysterectomy
immediately. Patients should be counseled on the risk of GTN
development. Postponement of treatment and watchful waiting in order to
fulfill a child wish could be an option as 85% of this patient
population does not develop GTN, just as we demonstrate with our case.
However, reliable diagnostics to monitor this period have not yet been
found.
Monitoring with hCG serum level measurements, transvaginal ultrasound,
hysteroscopy and MRI could be considered. However, the absence of an
abnormality does not exclude the presence of APSN as is clear from our
case. It was very remarkable that during the three years of monitoring
none of the diagnostics displayed anything abnormal, which can be
explained afterwards by the linear formation of the lesion. On MRI
imaging linear structures are difficult to detect, especially if the
lesion does not display malignant characteristics like restriction or
contrast-enhancement. In addition, experience is needed for the adequate
interpretation of placental MRI. Previous research showed a
significantly higher accuracy for placental MRI interpretation by
experienced radiologists compared to juniors, as juniors underestimated
the degree of placental infiltration (18.5% vs 0%, p=0.006) ¹⁰. Taking
these findings together, further research is needed to determine the
role of MRI in monitoring this patient population.
Currently, not enough is known about the reliability of hCG-levels and
diagnostic imaging to detect APSN progression to GTN. This legitimizes a
hysterectomy, even in the absence of increased hCG and/or abnormalities
on imaging. Further research should clarify which APSN progresses to ETT
or PSTT in order to establish protocols for monitoring and to establish
recommendations for follow-up if pregnancy is desired. A better
understanding of the clinical significance of APSN is needed in order to
prevent unnecessary (early) hysterectomies and to improve patient
counselling about the risks of postponing hysterectomy.
In conclusion, we demonstrate that pregnancy is possible after resection
of APSN but that APSN can remain present and undetectable for many
years. Further research is needed to form monitoring and treatment
recommendations for this rare and young patient group.