Spontaneous lung herniation due to congenital rib hypoplasia in an elderly patient

Dear Editor, Rib anomalies represent a diverse spectrum of congenital and acquired conditions, with abnormalities in rib quantity and structure found in approximately 2% of the general population.[1] Among these variations, rib hypoplasia constitutes a significant subset; one comprehensive analysis documented hypoplastic ribs in 10.27% of cases with rib anomalies.[2] These structural defects create anatomical vulnerabilities predisposing patients to complications such as lung herniation, characterised by protrusion of pulmonary tissue through chest wall defects.[3] Currently, there are no case presentations of lung herniation due to rib hypoplasia in adult patients. A 67-year-old male presented for outpatient consultation with complaints of progressive dyspnoea and left-sided chest pain worsening over the preceding two days. He was a retired factory worker with no significant occupational exposures. Relevant medical history included mild hypertension managed with lisinopril 10 mg daily, and a 30-pack-year smoking history, quit 15 years prior. He underwent umbilical and inguinal hernia repair 12 and 14 years ago. He denied any history of chest wall trauma or chronic respiratory conditions. Family history was non-contributory. Vital signs were stable: blood pressure 136/80 mmHg, heart rate 74 beats per minute, respiratory rate 16 breaths per minute, oxygen saturation 97% on room air. Physical examination revealed a well-defined, soft, reducible bulge measuring approximately 24 × 17 cm in the left lateral chest wall [Figure 1a], located between the eighth and tenth ribs in the mid-axillary line. The protrusion was more prominent during forced expiration and the Valsalva manoeuvre. Auscultation over the area revealed normal breath sounds.Figure 1: (a) A clinical image of the left part chest lesion; (b) CT scan coronal reconstruction demonstrating the lung herniation; (c) 3D CT scan chest reconstruction showing 9th rib hypoplasia; (d) 3D CT scan lung reconstruction indicates normal lung tissue in herniaInitial laboratory investigations including complete blood count and basic metabolic panel were within normal limits. Contrast-enhanced computed tomography of the thorax revealed a well-demarcated herniation of lung parenchyma [Figure 1b] through the left intercostal space between the eighth and tenth ribs [Figure 1c]. The herniated lung tissue maintained normal architecture with characteristic air density and showed no evidence of atelectasis, consolidation, or vascular compromise [Figure 1d]. Crucially, imaging demonstrated congenital hypoplasia of the ninth left rib with significant thinning. Pulmonary function testing was not performed due to a stable respiratory status. The absence of trauma, surgical interventions, and the presence of rib hypoplasia strongly supported the diagnosis of congenital rib hypoplasia with spontaneous lung herniation. Given the patient’s stable condition and personal preference, conservative management was adopted. The patient was educated about the condition, potential complications including incarceration, and the importance of avoiding activities that increase intra-thoracic pressure such as heavy lifting. Symptomatic management included acetaminophen for chest pain. No respiratory support was required. The patient was instructed to monitor for signs of complications including increasing size of the protrusion, severe pain, or respiratory distress. Surgical consultation was obtained, and options including open repair with mesh reinforcement or video-assisted thoracoscopic surgery were discussed. However, after consideration, the patient declined operative management. His decision was respected after confirming understanding of potential long-term implications. Lung herniation remains an exceptionally rare clinical entity, with spontaneous intercostal lung herniation being particularly uncommon and potentially associated with significant morbidity.[4] The literature primarily consists of isolated case reports. When occurring in association with congenital rib anomalies, lung herniation is frequently linked to syndromes such as Poland’s syndrome, which typically manifests with characteristic features including rib hypoplasia and occasionally lung herniation (reported in approximately 9% of cases).[5] The typical age of presentation for congenital rib anomalies with associated complications tends to be in childhood or early adulthood.[6] While traumatic lung herniation has been reported in elderly patients, the presentation of congenital rib hypoplasia with subsequent lung herniation in advanced age represents an unusual scenario. This delayed presentation challenges conventional understanding of the natural history of congenital rib anomalies.[7] Reporting this case in an elderly patient holds substantial clinical significance. It expands the known spectrum of presentation for congenital rib anomalies, demonstrating that these conditions may remain asymptomatic well into advanced age.[8] It highlights diagnostic challenges clinicians face when encountering rare congenital conditions in elderly populations, where symptoms may be attributed to common age-related pathologies. This case emphasises that congenital conditions should remain in the differential diagnosis across all age groups. Clinicians should maintain a high index of suspicion for such rare presentations to ensure appropriate management.