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,-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.