Uterine myomas are a common gynecologic pathology, affecting up to 70% of white and more than 80% of black women during their lifetime [1]. Reproductive-age women may experience abnormal uterine bleeding or bulk symptoms, such as pelvic pressure, fullness, or abdominal pain [2]. Moreover, uterine fibroids are found in 5-10% of infertility patients, and may be the only identifying cause of infertility in 1-2% [3]. FIGO type 2 myomas are a subgroup of submucosal myomas located within the endometrial cavity but that have greater than 50% of their mass within the myometrium [4].

These myomas can be highly symptomatic and yet difficult to fully resect via hysteroscopy in a single procedure, as there is often residual myoma inaccessible within the myometrium. This inaccessibility can be due to cavity anatomy, unreachable with a flat hysteroscopic morcellator, or due to concern for thermal injury with a hysteroscopic resectoscope [5,6]. It may take months for the remaining intramural portion of the myoma to migrate into the cavity, and thus multiple procedures are often needed to fully resect a submucosal myoma [7]. This can leave some with significant symptoms during the inter-procedural interval, and others with an inability to move forward with fertility treatment until a second or third procedure is completed. Moreover, bringing patients back for follow up ultrasounds and procedures is inconvenient, expensive, and inefficient.

Carboprost tromethamine is a synthetic analog of naturally-occurring prostaglandin F2a (PGF2a) that has been used for obstetrical uterine atony [4]. After binding to cell surface receptors, downstream signals cause smooth muscle contraction, mainly of the uterus and secondarily the gastrointestinal tract. Side effects can include vomiting, abdominal cramping, and diarrhea. Patients with asthma may be more susceptible to bronchospasm with carboprost. A 250 mcg/mL solution of carboprost tromethamine (Hemabate®, Pfizer, New York, NY) is readily available in most hospital pharmacies due to its common use in the management of postpartum hemorrhage [8].

Prior studies have demonstrated the intracervical use of carboprost to facilitate hysteroscopic resection of submucosal myomas. A study evaluating the efficacy of 250 and 125 mcg of intracervically injected carboprost found that 11 out of 13 myomas were completely resected [9]. A recent single-blind randomized trial of intracervical carboprost (50 mcg/mL) suggested an increased ability to resect large myomas (>5 cm) in a one-step hysteroscopic procedure when carboprost was compared to controls [10]. Another case report described successful resection of a sessile submucosal myoma using a carboprost solution of 50 mcg/mL [11]. At traditional concentrations of PGF2a, there is a risk of exacerbating asthma and provoking gastrointestinal symptoms. Additionally in some of these studies, full-dose carboprost intracervical injection was also associated with observable uterine contractions, which could worsen hysteroscopic visualization during resection.

Based on these prior studies, we hypothesized that instillation of a dilute PGF2a solution immediately adjacent to a submucosal myoma would promote fibroid expulsion into the cavity and improve the chances of initial procedure complete resection. Thus, the objective of this case series was to determine if injection of dilute carboprost at the endometrium/myoma border would facilitate one-step hysteroscopic resection of FIGO type 2 myomas.