Overlooked parahiatal hernia: diagnostic challenges and implications of a case report

Introduction

A parahiatal hernia (PHH) accounts for less than 1% of all diaphragmatic hernias (1). It is characterized by a protrusion of viscera through an abnormal diaphragmatic defect between the right and left crura (2). PHHs most commonly occur to the left of the gastroesophageal junction because of the protective barrier that the liver provides on the right side. This makes it more likely and easily mistaken for standard hiatal hernia due to their close anatomical proximity (3). The pathophysiology of PHH may be a result of a congenital defect in the pleuroperitoneal canal during development in utero or secondary to progressive weakening of the diaphragmatic muscle which occurs with age or obesity (4-6). Often PHH are discovered incidentally with a wide range of clinical presentations from asymptomatic to life-threatening if complications arise such as strangulation, obstruction, or perforation depending on the adjacent organ involvement or herniation degree.

We report a case of a PHH that most likely developed from diaphragmatic weakness induced by radiation therapy and was incidental noted during an esophagogastroduodenoscopy (EGD). We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-25-26/rc).

Case presentation

A 73-year-old female with a history of small cell lung malignancy (treated with radiation) and paroxysmal atrial fibrillation was admitted for symptomatic anemia with a hemoglobin level of 6.8 g/dL (reference: 12–16 g/dL) requiring a blood transfusion. Her past medical history was significant for a GI bleed requiring an EGD that revealed LA Grade A esophagitis with no hernia present. Of note, she was also not receiving any radiation therapy during the EGD at that time. Her medications also revealed that she was on apixaban 5 mg twice daily for paroxysmal atrial fibrillation which was held on arrival.

Review of systems was negative for hematemesis, hemoptysis, hematochezia, or melena but positive for odynophagia and epigastric pain following radiation therapy administered the previous day. Her radiation regimen was determined to be once a day for five days for a total of 6 weeks, and she was currently on week 4. The radiation was targeted to her malignancy which was located in the left lower lobe area. On arrival her vitals revealed a body mass index of 17.5 kg/m² and tachycardia to 101 beats per minute with a physical examination significant for cachexia and malnutrition. Labs confirmed a hemoglobin of 6.7 g/dL and pancytopenia. She received two units of packed red blood cells which increased her hemoglobin to 9.2 g/dL and she was admitted for symptomatic anemia with frequent hemoglobin monitoring every 8 hours.

The following day gastroenterology was consulted for evaluation of symptomatic anemia and odynophagia that was concerning for infectious esophagitis in the setting of immunosuppression. Endoscopy was deferred initially because the platelet count was less than 50,000 posing a high risk for bleeding and perforation. A computed chest without contrast revealed no compression of the esophagus but did reveal an irregular mass measuring 5.6 cm × 3.0 cm × 3.0 cm in the left lower lobe representing the malignancy.

On hospital day five endoscopy revealed LA Grade D esophagitis with active bleeding that was cauterized, a sliding hiatal hernia, an esophageal stricture, and a paraesophageal hernia. The stricture was dilated to 18 mm using a through-the-scope balloon. The patient was started on omeprazole, sucralfate suspension, and viscous lidocaine for a two-month course. The following day apixaban was reintroduced and a barium esophagram was attempted but the patient was unable to swallow the contrast to complete the study.

She was discharged on hospital day eight with improved symptoms and a stable hemoglobin at 8.9 g/dL. Her esophageal biopsies were negative for any viral [herpes simplex virus (HSV) or cytomegalovirus CMV)] or fungal (Candida) esophagitis. Upon reevaluation of EGD images the supposed paraesophageal hernia was reclassified as a PHH approximately 3.1 cm in size. At a two week follow up at the gastroenterology clinic her hemoglobin remained stable at 9 g/dL, symptoms improved, and no surgical intervention was deemed necessary for the PHH due to its relatively small size and lack of entrapment of any surrounding structures or organs.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

PHH are rare and often overlooked. They occur through a defect in the diaphragm just lateral to the esophageal hiatus usually on the left side because the right side is protected by the liver. Most hiatal hernias are sliding (95%) or paraesophageal (5%) hiatal hernias (7-9). PHHs are distinct but frequently misclassified. They are often found incidentally during surgeries like fundoplication making their true incidence hard to measure. Available data has only been noted in case reports such as Schediler et al. reporting an incidence of 0.2% while Planivelu et al. reported about 0.35% (1,2). Their rarity may reflect how easily they are mistaken for paraesophageal hernias especially on imaging which leads to under recognition in literature and clinical practice.

Our patient was initially diagnosed with a paraesophageal hernia during EGD. On closer review, the findings were more consistent with a PHH. This highlights how easily PHHs can be misclassified due to their location near the esophageal hiatus. The difference has clinical implications. In the setting of an emergent surgical intervention, PHH requires mesh repair to reinforce the weakening of the surrounding diaphragm which differs from a paraesophageal hernia which has a high risk of mesh erosion if placed (9). This case underscores the importance of maintaining a high index of suspicion and careful reviewing of imaging for optimal surgical planning if indicated.

The etiology of PHH remains incompletely understood. It can be primary (congenital) or secondary (acquired). Congenital PHHs are believed to arise from a weakness in the pleuroperitoneal canal due to incomplete obliteration of the pneumoenteric recess. Acquired PHHs may develop secondary to trauma, prior esophageal or diaphragmatic surgery, or progressively weakening of the diaphragm over time (4-6). Obesity is a well-established risk factor for hiatal hernias and may contribute to the development of PHH by an increase in intraabdominal pressure promoting diaphragmatic laxity (4). Diaphragmatic weakening is another commonly observed risk factor in the elderly due to age related muscle loss that can increase laxity of the diaphragm as well.

We believe the radiation therapy in our patient resulted in localized weakening of the left lower diaphragmatic side where the lung malignancy was located potentially leading to the development of the PHH. This is supported by the absence of a hernia on an EGD performed 2 years prior when the patient was not on any radiation therapy. Although she is elderly and some degree of laxity within the 2-year from the prior scope would contribute to the development of PHH, we do not believe that it alone could have contributed to the PHH. No previous literature has linked radiation to the development of PHH to our knowledge, making this a potentially novel association.

PHHs present like other hiatal hernias with vague symptomology such as nausea, vomiting, epigastric discomfort, and chest pain. As a result, paraesophageal hernia is commonly diagnosed. A chest radiograph for PHH and other hiatal hernias may reveal a retrocardiac gas bubble promoting further evaluation with barium swallow or thoracic computed tomography (CT) (2). However, these imaging modalities are not always reliable in detecting smaller PHHs, which was the case in our patient. CT chest on sagittal view showed the PHH while the axial views did not clear indicate the PHH (Figure 1). Some authors such as Scheidler et al. have attempted to define distinguishing imaging characteristics for PHH these findings remain inconclusive and lack broader validation (2).

Figure 1 Contrast tomography of the chest in the sagittal view. Red arrow indicating the parahiatal hernia. The yellow arrow indicating the trachea and the blue arrow indicating the esophagus.

The subtle nature of PHHs results in incidental discoveries often particularly during surgeries or endoscopies. Endoscopy can raise suspicion when two separate diaphragmatic defects are seen: one being the normal esophageal hiatus and a lateral defect connected by a tissue band suggesting PHH (Figure 2). In a series, 12 out of 14 patients were identified intraoperatively after initial endoscopy evaluation failed to provide definitive classification suggesting that EGD may not be a reliable modality (10).

Figure 2 The left and right images show the patient’s esophagogastroduodenoscopy. Findings: two orifices with the scope present in the esophageal hiatus and another lateral orifice representing the parahiatal hernia (white arrows).

While diagnostic laparoscopy can confirm PHH, it is generally reserved for cases when less invasive approaches are inconclusive. A contrast swallow study is also useful for visualizing the hernia but can provide additional information of coexisting esophageal conditions such as achalasia or gastroesophageal reflux disease (GERD) that may be contributing to the development of the PHH. In our patient’s case, the barium swallow could not be performed limiting our ability to rule out these contributory factors, an acknowledged limitation of this report.

Management of PHH is largely guided by the size and the presence of complications such as volvulus, obstruction, or incarceration and if adjacent organs are entrapped within the hernia. Asymptomatic individuals or those considered high risk surgical candidates such as our patient whose clinical frailty precluded operative intervention may be managed conservatively with monitoring (11). Our patient also did not have any adjacent organs that were entrapped within the PHH either. If surgery is indicated a laparoscopic approach is generally preferred and involves a hernia reduction, primary closure of the defect, and mesh reinforcement. In cases with large hiatal defect, hiatoplasty may also be necessary (1). Also, the presence of a concomitant sliding hiatal hernia should be assess intraoperative because it warrants the addition of a Nissen or partial fundoplication to address potential reflux symptoms and prevent recurrence (12).

Conclusions

PHH are rare and often misdiagnosed due to their anatomical similarity to paraesophageal hernias. Accurate identification is essential as management strategies differ based on size, symptoms, and surgical risk. This case highlights a possible link between radiation therapy and acquired PHH, an association not previously reported in literature underscoring the need for heightened clinical awareness and careful diagnostic evaluation.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-25-26/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-25-26/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-25-26/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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