A Rare Case of Right Middle Lobe Torsion after Right Upper Lobectomy: A Case Report

Abstract

Right upper lobe resection is a common surgical procedure in patients diagnosed with lung cancer. However, in certain cases, there may be an anatomical variation in which the fissure between the right middle and right lower lobes is more prominently developed than usual. This atypical development can create a predisposition to torsion of the right middle lobe, a complication that may occur during or shortly after the surgical procedure, especially if pneumopexy or surgical fixation of the lung is not performed. Torsion is a rare but serious complication that can lead to significant postoperative morbidity if not promptly recognized and treated. In this case report, we provide a detailed illustration of the radiologic findings associated with right middle lobe torsion that manifested following right upper lobectomy to excise a hamartoma located in the proximal bronchus of the right upper lobe.

INTRODUCTION

Lung torsion following lobectomy is a potentially life-threatening complication owing to the risk of acute respiratory failure. We present a rare case involving a patient who underwent robot-assisted thoracoscopic right upper lobectomy with lymph node dissection and subsequently developed right middle lobe torsion in the postoperative period. Right middle lobe torsion immediately after right upper lobectomy is an uncommon yet severe complication with significant implications for patient safety. The reported incidence of lobar torsion after surgery range from 0.3% to 0.9% (1,2). Although this complication is extremely rare, it is highly significant, with a mortality rate of up to 8.3% (1). Therefore, early detection is critical to facilitate timely intervention.

CASE REPORT

A 68-year-old man presented with a 2-month history of cough and dyspnea. He had a 25-pack-year smoking history but no significant medical history, and his family history was unremarkable. Physical examination revealed non-specific findings.

Laboratory testing revealed a complete blood count with a hemoglobin level of 13.8 gm/dL, hematocrit level of 42.2%, white blood cell count of 9320/m³, platelet count of 362000/mm³, and mean corpuscular volume of 51.0 fL. Automated differential blood tests revealed the following results: neutrophils, 62.2%; lymphocytes, 26.7%; monocytes, 6.1%; and eosinophils, 3.2%.

On initial chest radiography, the patient exhibited a poorly defined nodular opacity in the right upper lung field (Fig. 1A). Follow-up imaging performed 1 week later revealed the development of pulmonary consolidation with indistinct margins in the same region of the right upper lung field (Supplementary Fig. 1).

Fig. 1. A 68-year-old man with right middle lobe torsion.

A. Chest radiography shows a poorly defined nodular opacity (arrow) in right upper lung field.

B. Chest CT scan demonstrates an approximately 1.5-cm fatty nodule (arrow) suspected in proximal right upper lobar bronchus.

C. Post operative chest radiograph shows a well-defined oval-shaped opacity (arrows) of large area in the right lung field.

D, E. Axial and coronal CT scans show collapse and hemorrhagic consolidation with reversed halo sign (arrows) in the right middle lobe.

F. Whirling pattern of the middle lobe vessels (arrow) is demonstrated on the sagittal image.

Chest CT with contrast enhancement revealed a mass-like consolidation accompanied by a diffuse bronchial obstruction in the right upper lobe. Additionally, a 1.5-cm fatty nodule was suspected in the proximal right upper lobar bronchus (Fig. 1B). Based on radiological findings, the presence of a fat-containing tumor obstructing the right upper lobar bronchus with resultant post-obstructive pneumonia was suggested.

Subsequent bronchoscopy revealed an oval, pinkish, soft nodule that obstructed the right upper lobar bronchus (Supplementary Fig. 2A). PET/CT imaging demonstrated atelectasis with diffuse, mild hypermetabolism in the right upper lobe, but did not show any high fluorodeoxyglucose uptake in soft tissue nodular lesions obstructing the right upper lobar bronchus (Supplementary Fig. 2B). Based on comprehensive evaluation, a benign tumor, such as a lipoma or hamartoma, was considered a plausible diagnosis. Hypermetabolism observed on PET/CT was presumed to be attributable to atelectasis.

Seven days after admission, the patient underwent robot-assisted thoracoscopic lobectomy and radical lymph node dissection. Chest radiographs obtained on postoperative days 1 and 2 indicated satisfactory lung expansion, with no significant abnormalities. However, 3 days after surgery, the patient presented with fever and mild dyspnea. Follow-up chest radiography revealed a well-defined oval-shaped opacity in a large area, with a persistent pneumothorax in the right lung field (Fig. 1C). Over time, the opacity progressively increased and was accompanied by the onset of hemoptysis. CT revealed collapse and hemorrhagic consolidation in the right middle lobe, with a reversed halo sign and moderate pneumothorax (Fig. 1D, E). In addition, the sagittal image showed whirling of the middle lobe vessels (Fig. 1F).

Suspecting torsion, the patient underwent an exploratory thoracotomy. Direct visualization revealed counter-clockwise torsion of the right middle lobe around the pedicle axis. Emergency right middle lobectomy was subsequently performed. Gross examination of the specimen revealed extensive hemorrhage within the right middle lobe (Supplementary Fig. 3). Pathological analysis showed no distinct mass but confirmed the presence of hemorrhagic consolidation and severe congestion. The patient’s clinical condition improved, and he was discharged 10 days after the second surgery.

This case report was exempt from the ethical approval in our institution. This study was performed according to the latest ethical principles in the Declaration of Helsinki (2013).

DISCUSSION

Pulmonary torsion is an infrequent yet potentially life-threatening complication that can arise following thoracic surgery, with a reported incidence between 0.3% and 0.9% (1,2). This condition is characterized by the twisting of the lung lobe or entire lung, leading to compromised blood flow and ventilation. Patients who develop pulmonary torsion may present with clinical symptoms, such as progressive lung consolidation or persistent pneumothorax, which can be observed on serial postoperative chest radiographs. Early recognition and prompt intervention are critical for improving patient outcomes, as delayed diagnosis and treatment can lead to severe complications, including lung infarction, hemorrhagic necrosis, respiratory failure, and even death (3). Therefore, a high index of suspicion is necessary in the postoperative setting to ensure timely management and minimize the risk of life-threatening consequences.

There are several risk factors for torsion of the right middle lobe. The main risk factors include insufficient fixation of the remaining lung, which can increase the risk of middle-lobe torsion. Changes in the intrathoracic pressure or patient position can have an impact. Patients with preexisting lung conditions may be at greater risk. The formation of adhesions in the pleura after surgery restricts lung movement. Additionally, the overall health status of the patient or anatomical variations may contribute to risk factors (4,5).

In our case, according to the surgical records, there was severe pleural adhesion due to inflammation of the right upper lobe, and both the right upper and middle lobes were in an incomplete fissure state, with the distance between the right middle lobar bronchus and carina being small. A short distance from the carina to the middle lobe orifice could be a risk factor for kinking of the middle lobar bronchus after right upper lobectomy. Additionally, the presence of dense scar tissue and post-inflammatory tissue made dissection challenging due to the risk of easy bleeding, complicating the pneumopexy procedure.

Prompt diagnosis of pulmonary torsion can be particularly challenging because its presentation often overlaps with that of other thoracic conditions. It is essential to differentiate pulmonary torsion from other similar conditions, such as mucus impaction or pneumonia, which may show clinical improvement with chest physical therapy and effective antibiotic treatments. Physical findings associated with pulmonary torsion, including fever, tachycardia, dyspnea, and decreased breath sounds, are nonspecific and can be mistaken for other respiratory disorders. These overlapping symptoms complicate the clinical picture, making it difficult to reach a definitive diagnosis based solely on a physical examination. Therefore, healthcare providers must maintain a high degree of clinical suspicion and use appropriate imaging studies to distinguish pulmonary torsion from other potential causes of symptoms.

The primary diagnostic clues for lung torsion are typically identified using a combination of radiographic and bronchoscopic findings. Radiographically, lung torsion may present with characteristic features, such as homogeneous consolidation on chest radiographs, which can suggest the presence of an obstructed lobe. On CT, the absence of contrast enhancement in the affected lobe is another critical indicator of impaired blood flow and potential vascular compromise (3,6,7). A thorough bronchoscopic examination further aids in diagnosis by allowing direct visualization of the bronchial tree. During a bronchoscopy, clinicians may observe an abnormally tight and obstructed orifice in the affected lobe, which is a key sign of torsion (5). The integration of these diagnostic tools with radiographic imaging and bronchoscopy provides a comprehensive approach for accurately identifying lung torsion, enabling timely intervention to prevent serious complications.

Tamizuddin et al. (8) reported distinguishing imaging features of right middle lobe torsion. Key indicators for early recognition of this rare yet clinically significant condition include a reversed halo sign, an increased coronal bronchial angle on CT, a greater proportion of ground-glass opacity, fissural convexity, and an enlarged lobe volume on CT. The integration of radiographic, bronchoscopic, and clinical findings should guide clinicians towards an accurate diagnosis. It is crucial for radiologists to recognize this infrequently encountered condition because lobar torsion has significant clinical implications.

Among the various radiological findings reported indicating right middle lobe torsion, several important imaging characteristics were observed. Chest radiography revealed a gradually developing lobar hazy opacity accompanied by a persistent pneumothorax that did not resolve over time. Additionally, CT revealed significant findings including a reversed halo sign, ipsilateral pneumothorax, and swirling of blood vessels near the hilum, which further supported the diagnosis.

Additionally, CT angiography successfully identified the obstructed right middle lobe bronchus and avascular nature of the infected and displaced right middle lobes. This detailed information, obtained from present-day multislice high-resolution CT scanners with the correct CT protocols, seems to diminish the need for further confirmation using other methods (9).

The right middle lobe is the most commonly affected lobe. Pneumopexy is a critical procedure for preventing this complication (10). To mitigate the risk of lobar torsion, pneumopexy involving the use of sutures to anchor the right middle lobe to the lower lobe following right upper lobectomy should be performed in all cases (7). If lung torsion is suspected, exploratory thoracotomy should be performed immediately.

In conclusion, right middle lobe torsion is a rare yet serious complication that can occur following right upper lobectomy. Given its rarity, it may not always be immediately considered in the differential diagnosis. However, radiologists must remain vigilant and include this condition in their assessment when evaluating postoperative scenarios. Early recognition of lobar torsion is critical, because timely intervention can significantly affect patient outcomes. Therefore, heightened awareness of this uncommon condition, along with its associated radiological findings, is essential for radiologists to ensure prompt diagnosis and effective treatment during the early postoperative period. By doing so, they can help prevent severe complications that may arise from delayed or missed diagnoses, ultimately contributing to improved patient care and recovery.

Supplementary Materials

The Supplement is available with this article at http://doi.org/10.3348/jksr.2024.0110.

Supplementary Fig. 1

Follow-up imaging performed 1 week later reveals the development of pulmonary consolidation characterized by indistinct margins occurring in the same region of the right upper lung field as previously noted (arrow).

Supplementary Fig. 2

Findings of bronchoscopy and PET/CT.

Supplementary Fig. 3

Gross examination of the specimen reveals a significant and extensive area of hemorrhage localized within the right middle lobe.