A 25-year-old gravida 3 para 2 pregnant woman with dichorionic diamniotic twins was referred to our fetal care center at 22 0/7 weeks’ gestation for a large oral cystic mass in twin A. There were no other anatomical concerns; both fetuses were appropriately grown with normal amniotic fluid volumes. The woman’s medical and family history were unremarkable. Our initial evaluation included ultrasonography (US) examination, fetal magnetic resonance imaging (MRI), and echocardiogram to further evaluate the oral mass, identify potential associated congenital anomalies, and guide management decisions.Fetal US (Figure 1) and MRI (Figure 2), performed at 23 3/7 weeks’ gestation, showed a simple-appearing cystic oral mass in twin A, a male fetus. The lesion measured approximately 2.7 × 1.8 × 2.4 cm on US, concordant with MRI measurement. It protruded through the oral cavity, preventing the fetal lips from closing, and displaced the tongue superiorly and posteriorly. The mass appeared to arise from the floor of the mouth and did not have solid components or an identifiable feeding vessel. There was no evidence of extension into the neck, and the mandible appeared intact. The nasopharynx, posterior pharynx, and cervical airway were patent. There were no other structural anomalies identified in twin A. Twin B, a female fetus, was appropriately grown with normal anatomy for gestational age on US and MRI.Families referred to our fetal care center with a prenatal diagnosis of a fetal oral cyst undergo a comprehensive multidisciplinary evaluation, involving maternal-fetal medicine specialists, neonatologists, pediatric and fetal surgeons, and otolaryngologists (ENTs), with additional input from fetal radiologists. Counseling is based on the characteristics of the lesion, mainly its size, structure, location, and potential impact on adjacent structures. Careful attention should be given to the patency of the upper airway and esophagus.While the differential diagnosis of a fetal oral cyst is broad, imaging characteristics can help refine it. For a mass with features similar to those observed in our patient, potential etiologies include the following: Congenital ranulaThyroglossal duct cystForegut duplication cystLymphatic malformationCongenital ranulas are retention cysts that develop when sublingual or submaxillary gland ducts are disrupted, resulting in mucus leakage and cyst formation.1,2 They occur in approximately 0.7% of live births with prenatal diagnosis being extremely rare.3,4 On imaging, a ranula appears as a well-circumscribed homogeneous cystic lesion typically confined to the sublingual space.5–7 In rare cases, it may extend into the submandibular region, classified as a “diving” or “plunging” ranula. Importantly, ranulas are often pseudocysts confined within connective tissue, without a true epithelial lining.5 Ranula fluid, when drained, is expected to demonstrate high protein content and elevated amylase levels consistent with salivary gland origin.8 However, 1 case series of 37 confirmed plunging ranulas found that nearly one-third had low-to-modest amylase levels (ranging approximately 3–100 U/L).9 While many remain asymptomatic or resolve spontaneously, large ranulas can cause oropharyngeal compression and airway compromise.10A thyroglossal duct cyst is the most common congenital neck mass, but a sublingual presentation is unusual. On imaging, thyroglossal duct cysts resemble simple ranulas with well-defined borders that lack solid components.11,12 A distinguishing feature on US is motion of the cyst along the thyroglossal tract with tongue movements. This sign may not be appreciated on fetal imaging, particularly before 24 weeks’ gestation, when tongue movements are not reliably visualized.13 Oral cavity thyroglossal duct cysts arise from the foramen cecum and would, therefore, be expected to displace the tongue anteriorly and inferiorly.Foregut duplication cysts are developmental anomalies that arise from the foregut-derived gastrointestinal tract, with a reported incidence of 0.02%.14,15 They are cystic in nature, lined by foregut epithelium and covered by a smooth muscle layer. While they are most commonly located in the mediastinum and abdomen, occurrence in the oral cavity has been reported.16–19 Therefore, while rare, this diagnosis remained a consideration in our differential.Among vascular etiologies, hemangiomas and other arteriovenous malformations are less likely when there is a lack of solid components within the lesion and an absence of vascularity on US. A lymphatic malformation, however, remained a viable possibility. Oral lymphatic malformations are typically cystic, distinguishing them from other vascular lesions.20,21 Importantly, these lymphatic cysts are often large and demonstrate trans-spatial characteristics. They tend to cross anatomical compartments and involve multiple contiguous spaces within the head and neck. In our patient, although no trans-spatial extension was observed at the time of initial evaluation, the considerable size of the lesion prevented us from excluding a lymphatic malformation from our differential considerations.In contrast to the trans-spatial extension of oral lymphatic malformations, thyroglossal duct cysts generally remain midline, and ranulas and oral foregut duplication cysts are usually midline or slightly off-midline.20 An exception to this anatomical distinction is that “diving” or “plunging” ranulas may mimic the trans-spatial pattern characteristic of lymphatic malformations.22,23Given the imaging findings of a simple cystic lesion without evidence of trans-spatial involvement in this fetus, a simple congenital ranula was the most likely diagnosis. This was based on the relative prevalence of ranulas among congenital cystic lesions in this anatomical region in conjunction with the characteristic imaging appearance. Nonetheless, an oral foregut duplication cyst, thyroglossal duct cyst, and lymphatic malformation remained on the differential and were discussed with the family. Teratomas such as epignathus, or other oropharyngeal tumors such as congenital epulis, seemed unlikely given the simple appearance of the cyst. Additionally, the absence of enhancement or restricted diffusion on diffusion-weighted MRI made dermoid and epidermoid lesions unlikely.While each of the 4 potential etiologies for our patient is benign in nature, they all carry the potential for serious complications and warrant close follow-up. If the mass continues to grow, it can lead to airway obstruction and swallowing difficulties resulting in polyhydramnios.24 In the fetus in this case, fluid in the stomach and normal amniotic fluid volume supported the absence of airway obstruction and esophageal compression. However, the superior and posterior displacement of the tongue raised concern for potential glossoptosis, which could lead to upper airway obstruction as the pregnancy progressed. Therefore, serial fetal US scans were recommended to monitor the growth of the lesion, assess airway patency, and evaluate amniotic fluid volume.In addition to weekly US by the obstetrical team, the patient was closely followed by our fetal care center throughout the pregnancy. Both twins continued to have appropriate growth rates. The cystic mass in twin A rapidly increased in size, doubling in volume by 27 4/7 weeks’ gestation and becoming nearly 5 times larger by 34 4/7 weeks. Despite this, the amniotic fluid volume remained normal. Amniotic fluid was seen in the airway and stomach, suggesting the mass was nonobstructive (Table 1). To assess its growth relative to the fetus, the cyst volume was normalized to the head circumference (Figure 3). Despite the enlargement of the mass at a rate exceeding that of the fetus, it did not require fetal intervention because there was no evidence of complete airway obstruction.Given the large size of the cystic structure, the rapid rate of growth, the twin gestation, and increasing concern for evolving airway obstruction as the pregnancy advanced, a shared decision was made between our multidisciplinary team and the family to proceed with a scheduled cesarean delivery at 36 3/7 weeks’ gestation. Although an ex utero intrapartum treatment (EXIT) was not indicated, we anticipated a potential risk of respiratory distress at birth and established a delivery room plan that included immediate placement of a nasopharyngeal airway. If the neonate remained stable with spontaneous and effective respiratory effort, the cyst would be lanced in the delivery room, with definitive surgical planning during the following days or weeks. If the neonate developed severe respiratory distress or apnea, the team would then proceed with nasal intubation via bronchoscopy, reserving emergent tracheostomy as a last resort. On the morning of the scheduled cesarean delivery, the pregnant woman presented with spontaneous rupture of membranes. Fetal surgery, neonatology, and ENT teams were present at delivery and prepared to manage all anticipated scenarios.A 2520-g appropriately grown boy was delivered via cesarean birth and immediately transferred to the resuscitation room. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. A large cystic lesion was noted arising from the ventral surface of the tongue and protruding from the oral cavity (Figure 4A). The mass extended along the floor of the mouth, predominantly on the right side, occupying the entire floor of the mouth and extending posteriorly. The infant demonstrated vigorous crying but was noted to have labored breathing. A nasopharyngeal airway was placed in the right nasal cavity to help alleviate obstruction caused by glossoptosis. This was effective, and the patient was able to maintain appropriate oxygen saturations, except for brief intermittent desaturation episodes requiring some blow-by oxygen for several minutes.Given the patient’s stable condition and the concern for potential vascular disruption, the decision was made to needle aspirate the lesion rather than lancing it (Figure 4B). Around 60 mL of straw-colored fluid was aspirated from the anterior aspect of the cyst and sent for cell count and amylase analysis. As the cyst was decompressed, the infant’s respiratory effort improved, and he began moving his tongue more evenly and freely (Figure 4C). The airway was then assessed using a flexible fiberoptic scope. There were no masses or lesions in the right nasal cavity, and the choana was widely patent. The adenoids appeared normal. There was no significant collapse or prolapse of the tongue base. The true vocal folds were mobile bilaterally and normal appearing with no masses or lesions. The arytenoids were normal in appearance. The epiglottis was sharp with no evidence of significant laryngomalacia. The visualized portion of the subglottic airway appeared normal and widely patent. The infant was then transferred to the neonatal intensive care unit (NICU) for further evaluation and management.The co-twin, delivered second, required no resuscitation and received routine newborn care.The infant was admitted to the NICU in room air. Head and neck US performed at admission showed a remaining simple anechoic cyst at the floor of the mouth inferior to the tongue, measuring 0.8 × 0.6 × 0.8 cm (Figure 5A). There was no internal flow on Doppler imaging. Analysis of the fluid drained in the resuscitation room demonstrated an amylase level of 9 U/L, and there were 13 600 total nucleated cells. Manual differential cell count could not be performed due to the abundance of degenerated white blood cells. Following multidisciplinary discussions, the team decided to monitor the progression of the mass, respiratory status, and oral intake over the next several days, repeat head and neck US as clinically indicated, and ultimately perform an MRI of the head and neck for better characterization of the lesion.The infant did not require respiratory support throughout his NICU stay. A nasal trumpet was kept at bedside but was never needed. He initially required a nasogastric tube for enteral feeds, but with the involvement of speech therapy, his oral intake quickly improved. On examination, the cystic mass appeared to slowly reaccumulate fluid over the next few days, with posterior displacement of the tongue. Nonetheless, the infant maintained a patent upper airway without any signs of respiratory distress and continued to take more than half of his feeds orally. Head and neck US was repeated several times throughout the hospital stay. At 4 and 10 days of age, a large and irregular fluid pocket with internal debris was noted just superior to the previously appreciated simple-appearing cystic lesion, more to the midline, and possibly communicating with it. Ongoing surrounding inflammatory changes were also noted (Figure 5B). An MRI of the head and neck was performed at 11 days of age and again showed 2 communicating fluid collections: a slightly complex collection within the anterior oral cavity, centered to the midline, inferior to the tongue, T2 hyperintense and minimally T1 hyperintense, measuring 1.7 × 1.7 × 2 cm in its greatest dimensions and containing blood products; and posteriorly, a simple-appearing cyst just inferior to the tongue base and superior to the muscles forming the floor of the mouth, measuring approximately 0.7 × 0.5 × 0.5 cm. The tongue was noted to be displaced superiorly but was otherwise normal in appearance (Figure 5C).Under the impression that the cyst may be due to a vascular lymphatic malformation, the infant underwent sclerotherapy with doxycycline at 18 days of age, and around 10 mL of fluid was drained. He was intubated prior to the procedure without any difficulties and was immediately extubated afterwards. His postoperative course remained uncomplicated with easy work of breathing, no desaturations, and appropriate oral intake. While some edema to the right floor of the mouth was noted postoperatively with some fluid reaccumulation, the infant’s respiratory status and oral feeding volumes remained unaffected. He achieved full enteral feeds by mouth at 19 days of age. Repeat head and neck US was performed prior to discharge and again showed the cystic lesions with increased echogenicity and more internal debris in the superior and anterior one, likely a sequela of sclerotherapy; but overall, both lesions were similar in size to prior (Figure 5D). Counseling was provided regarding the potential for continued reaccumulation of fluid and the potential need for repeat aspiration and/or repeat sclerotherapy in the future. He was discharged home at 24 days of age with ENT follow-up planned 2 weeks after discharge.One after the infant presented to the with cyst reaccumulation and associated with increasing feeding was ultimately performed by ENT at 37 days of age. the cyst was found to be within the tongue it an with a protruding a feature that likely for it appearing as 2 communicating cysts on imaging. The lesion was in its and sent for (Figure The procedure was and the infant remained stable postoperatively without further a cyst lined predominantly by with some of epithelium containing and to the epithelium were of tissue, and smooth muscle were present within of the and of the cyst was by findings were consistent with a diagnosis of an oral foregut duplication oral masses can be classified based on or of or vascularity (Table and vascular malformations are the most common oral and cervical masses include ranula or in the floor of the oral cavity, oral duplication developmental anomalies, dermoid or epidermoid and 3 the characteristics of the 4 most likely in our patient based on imaging diagnosis of a fetal oral mass is typically made by prenatal US. fetal anatomy scans performed between 18 and 22 weeks’ gestation include comprehensive of the head and neck, both and If an oral lesion is US can help its size, or and Additionally, it of airway patency and fetal which is for potential MRI is an oral mass is identified on prenatal US. MRI superior contrast and can the between the mass and surrounding in the of the of the lesion and any potential airway imaging should not on the oral mass but also on the following of and of the mass and tongue to adjacent particularly the or absence of a and amniotic fluid volumes. This is for and planning appropriate management and rapidly oral masses can airway and oropharyngeal which may fetal and the of course of fetal oral masses on the of airway and oropharyngeal as as the of and potential arteriovenous on the could the to to and an can as an for oropharyngeal obstruction and is a of airway in the fetus and respiratory distress at If airway obstruction is not anticipated and at the time of delivery, it could lead to and vascularity within the lesion in a to and increasing the risk of a fetal oral mass to or in utero may be to airway patency and neonatal management include needle aspiration or to the lesion (Figure reported in the for management of fetal oral could be to the management of large simple oral aspiration be the fluid the cyst is and to In such by of the cyst could be an these or be an procedure would then be to an airway before full delivery (Figure Following the head and neck of the fetus are and a is performed to airway If flexible would then 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and of delivery should not be If significant and fetal are or a planned cesarean delivery could be in the absence of a planned a multidisciplinary team from the time of the initial fetal evaluation, a and plan and all team are at the time of fetal and delivery are to and neonatal In the of a should be to team This plan delivery the neonate would and appropriate care from a and team (Figure the respiratory status of the infant should be assessed and the appropriate level of respiratory support of the cyst in the delivery room may be to and airway of a nasopharyngeal airway should be to any obstruction resulting from the posterior displacement of the tongue by the oral cyst. management on the size, location, and impact of the lesion on the respiratory status and to by may include and complete of the lesion, and/or sublingual gland to our case, foregut duplication cysts are rare congenital anomalies that occur when of foregut-derived epithelium during have been with retention of foregut of gastrointestinal during tongue and of epithelial The most common of foregut duplication cyst is the cyst and is to from an of the respiratory during foregut In some cases, duplication cysts are found in with and are then classified as This a shared with of the foregut and duplication cysts can arise along the gastrointestinal tract, they are most found in the mediastinum or the Head and neck location, as seen in our patient, is extremely it occur within the head and neck, the oral cavity, particularly the anterior of the tongue and anterior floor of the mouth, is the most commonly reported On imaging, oral foregut duplication cysts may be to from more common congenital oral cysts such as thyroglossal duct although for the anterior oral cavity can a diagnosis is and of 3 the of a smooth muscle in the cyst a by foregut-derived and a to a portion of the The epithelial may of or simple cells. epithelial cell may within the lesion, as seen in our or can be for oral foregut duplication cysts include and definitive surgical may but is expected and complications may arise definitive is cysts carry and epithelium is in rare cases, surgical both and therapy, with when the epithelial is case the that a twin gestation to the evaluation and management of fetal oral of and delivery planning the airway of the fetus the potential and neonatal for the In rare and of complete airway obstruction 1 fetus in a twin gestation, have been reported in which the twin required However, the decision to an procedure is more in twin because of the to the and both planning and remain the most effective to If an procedure delivery of the without complications is the and planning are to for both oral cystic masses require evaluation given the potential risk for airway serial imaging, and multidisciplinary planning are to guide surrounding fetal and the and of Although congenital ranulas are among the most common etiologies, rare such as oral foregut duplication cysts should be particularly when lesions arise from the anterior floor of the mouth or tongue. room airway management and neonatal evaluation are to a to in the case of oral foregut duplication definitive surgical both and This the of care and management to for with congenital oral cystic oral masses can be on prenatal US and should to a fetal care center for multidisciplinary MRI is recommended an oral mass is identified on prenatal US. Fetal should be on the of the mass to adjacent particularly the the or absence of and a stomach, and the or absence of the of fetal oral the of is for airway and can as a for fetal procedure can be performed as a last to fetal airway obstruction and a airway prior to multidisciplinary at a and delivery plan is to and neonatal oral foregut duplication cysts should be when a cystic lesion from the anterior floor of the mouth or the anterior of the tongue. diagnosis examination, and complete surgical the treatment of of congenital anomalies of the mouth, and regarding resuscitation of a newborn
Saneh et al. (Mon,) studied this question.