[Pregnancy and extra-gastrointestinal stromal tumor: an exceptional association]

Diagnosis and management of high risk gastrointestinal stromal tumor in first trimester pregnancy: A case report and review of the literature

Objective

There are less than 20 reported cases of gastrointestinal stromal tumors in pregnancy. Of these reported cases, there are only two that detail GIST in the first trimester. We report our experience with the third known GIST diagnosis in the first trimester of pregnancy. Notably, our case report highlights the earliest known gestational age at time of GIST diagnosis.

Methods

We conducted a literature review of GIST diagnosis in pregnancy via PUBMED, using a combination of the following terms: (pregnancy or gestation) and (GIST). We utilized Epic for chart review of our patient's case report.

Results

A 24 year old G3P1011 presented to the Emergency Department at 4w6d by last menstrual period (LMP) with worsening abdominal cramping, bloating, and associated nausea. Physical exam revealed a large, mobile, nontender mass palpated in the right lower abdomen. Transvagianl ultrasound noted the presence of a large pelvic mass of unknown etiology. Pelvic magnetic resonance imaging (MRI) was obtained for further characterization, revealing a 7.3× 12.4 × 12.2 cm mass with multiple fluid levels, centered in the anterior mesentery. Exploratory laparotomy was performed with en bloc resection of small bowel and pelvic mass, with pathology demonstrating a 12.8 cm spindle cell neoplasm compatible with GIST and notable for a mitotic rate of 40 mitoses/50 high power field (HPF). Next generation sequencing (NGS) was pursued in order to predict tumor responsiveness to Imatinib, which revealed a mutation at KIT exon 11, suggesting a response to tyrosine kinase inhibitor therapy. The patient's multidisciplinary treatment team, consisting of medical oncologists, surgical oncologists, and maternal fetal medicine specialists, made the recommendation for adjuvant Imatinib therapy. The patient was offered termination of pregnancy with immediate initiation of Imatinib, as well as continuation of pregnancy with either immediate or delayed treatment. Interdisciplinary counseling focused on both the maternal and fetal implications of each proposed management plan. She ultimately elected termination of pregnancy, and underwent an uncomplicated dilation and evacuation.

Conclusions

GIST diagnosis in pregnancy is exceedingly rare. Patients with high-grade disease encounter a multitude of decision-making dilemmas, often with competing maternal and fetal interests. As additional cases of GIST in pregnancy are added to the literature, clinicians will be able to implement evidence-based options counseling for their patients. Shared decision-making is contingent upon patient understanding of diagnosis, risk of recurrence, available treatment options, and the treatment-related implications on maternal and fetal outcomes. A multidisciplinary approach is crucial for optimization of patient-centered care.

A Novel PRKAR1B-BRAF Fusion in Gastrointestinal Stromal Tumor Guides Adjuvant Treatment Decision-Making During Pregnancy

Gastrointestinal stromal tumors (GISTs) are rare in pregnancy, with only 11 reported cases. Adjuvant imatinib therapy, which targets the most common driver mutations in GIST (KIT and PDGFRA), is recommended for patients with high-risk GIST, but it has known teratogenicity in the first trimester. A 34-year-old G3P2 woman underwent exploratory laparotomy at 16 weeks' gestation for a presumed adnexal mass. Surgical findings included normal adnexa and a 14-cm solid small bowel mass. The mass was resected en bloc with a segment of jejunum followed by a primary anastomosis. Histopathology and genomic analyses demonstrated a GIST with high-risk features but lack of KIT/PDGFRA mutations and identified the presence of a previously unreported, pathogenic PRKAR1B-BRAF gene fusion. Given her tumor profile, adjuvant therapy with imatinib was not recommended. GIST is rare in pregnancy, but can masquerade as an adnexal mass in women of childbearing age. Because neoadjuvant/adjuvant imatinib has risks of teratogenicity, tumor molecular profiling is critical as we identified a previously unreported gene fusion of PRKAR1B with BRAF that is predicted to be imatinib-resistant. In this case, testing provided the rationale for not offering adjuvant imatinib to avoid unnecessary toxicity to the patient and fetus.

Gastrointestinal stromal tumors during pregnancy: a systematic review of an uncommon but treatable malignancy

Although modern social structure and medical advances have led to the increasing number of women childbearing in older age, cancer remains a rare diagnosis during pregnancy. There is little given information throughout the literature concerning gestation associated with the coexistence of gastrointestinal stromal tumor (GIST). In this review, we present 12 reported cases of GIST during pregnancy and we discuss the maternal and fetal outcome, as well as the therapeutic plan that was followed in each situation. From the collected data, 8 out of 12 cases had an uneventful outcome of their fetus. In 11 out of 12 cases surgical excision of the tumor was the treatment of choice, while seven women were treated with imatinib. Two of them were already on imatinib therapy during conception due to preexisting GIST diagnosis. Surgery remains the gold standard for the treatment of local or resectable GIST, while published data concerning the use of imatinib during pregnancy indicate that teratogenicity or fetal loss might be induced, especially if given during the first trimester of pregnancy. GIST during gestational period is a rare tumor in which a multidisciplinary approach should be designed, taking always into consideration that it has a favorable outcome on targeted treatment.