Necrobiotic Pulmonary Nodules in Ulcerative Colitis: A Rare Case Report

Introduction

Necrobiotic pulmonary nodules represent an exceptionally rare extraintestinal manifestation of inflammatory bowel disease (IBD), comprising conditions such as Crohn’s disease and ulcerative colitis. These nodules pose significant diagnostic challenges, often mimicking autoimmune pathologies like sarcoidosis, rheumatoid arthritis, and other granulomatous diseases, thereby complicating the clinical management of affected patients [1]. The rarity and nonspecific clinical presentation of necrobiotic pulmonary nodules necessitate reliance on a combination of radiological and histological findings for accurate diagnosis. Herein, we discuss a 36-year-old woman with necrobiotic pulmonary nodules, underscoring this rarity and application of a surgical diagnostic approach.

Case Report

A 36-year-old woman with known ulcerative colitis presented with a persistent cough while on a trip to India in June 2023. Upon returning to the UK, her primary care physician prescribed antibiotics for 5 days, which did not lead to any improvement. She was subsequently reviewed by a respiratory physician who as part of her investigations performed a computed tomography (CT) scan (Figure 1A–1D). The CT scan revealed multiple bilateral lung nodules, the largest being in the left lower lobe, measuring 21 mm (Figure 1A). A positron emission tomography (PET) scan was then requested which demonstrated increased fluorodeoxyglucose (FDG) uptake along the left main bronchus extending to the left lower lobe bronchi (Figure 2A), heightened activity in the bilateral hilar nodes (Figure 2C), a focus of uptake associated with nodular thickening of the trachea at the level of the thoracic inlet (Figure 2D), and unexpected uptake at the right sixth rib (Figure 2E). The largest pulmonary nodule exhibited significant avidity (Figure 2B). An endobronchial ultrasound-guided biopsy was conducted, sampling lymph nodes at stations 10R and 10L, which showed necrosis without evidence of malignancy, and bronchoalveolar lavage was negative for tuberculosis. While the 21-mm nodule in the lower lobe of the left lung was considered accessible for CT-guided biopsy, several factors discouraged this approach. The nodule’s location behind the rib, compounded by the patient’s anxiety, posed significant challenges. The decision against a more aggressive pursuit was primarily due to the patient’s heightened anxiety and discomfort with the procedure. Despite initial attempts, the procedure was abandoned by the operators, prioritizing the patient’s well-being. Instead, they decided to seek a more definitive diagnostic approach through video-assisted thoracoscopic surgery (VATS). She was eventually referred for uniportal VATS for a wedge resection of the largest nodule in the left lower lobe. The histology from the VATS procedure revealed a necrotic nodule surrounded by histiocytes, fibroblasts, and granulation tissue, with no presence of epithelioid histiocytes. Histochemical stains for acid-fast bacilli and fungi; Ziehl-Neelsen, Periodic Acid-Schiff, and Grocott, were negative, showing no evidence of atypia or malignancy. Tuberculosis cultures were also negative. Post-surgery, the patient has shown a good recovery with noticeable improvement in her cough symptoms and radiologically stable condition evident on X-ray (Figure 3).

Discussion

Extraintestinal manifestations of IBD, particularly ulcerative colitis, have been recognized since the 1960s, with pulmonary involvement, such as chronic bronchitis, bronchiectasis, interstitial lung disease, and necrobiotic pulmonary nodules, being documented [2–5]. The incidence of necrobiotic pulmonary nodules in ulcerative colitis, while rare at 5.3%, represents a significant clinical challenge due to its diagnostic complexity [6–8]. Unlike other forms of pulmonary involvement, necrobiotic nodules often require a diagnosis of exclusion, given their rarity and nonspecific presentation.

In line with previously reported cases, necrobiotic pulmonary nodules predominantly affect younger individuals (<30) with a known history of IBD, presenting typically with respiratory symptoms [6]. However, our case diverges slightly from this classical presentation in that the patient was slightly older than the usual age bracket for necrobiotic pulmonary nodules, at 36 years old. Unlike most reported cases, our patient’s primary complaint was only a persistent cough that started after her trip to India, which is an atypical onset for such conditions [8,7]. This distinction underscores the necessity of a vigilant approach in IBD patients presenting with any form of respiratory symptoms, given the potential for these nodules to act as a nidus for infection [9].

Radiologically, our case aligns with the classical findings described in the literature: the presence of bilateral pulmonary nodules, with the largest nodule measuring 21 mm, fitting within the reported range of 8 to 30 mm [10,11]. The PET scan’s revelation of metabolic activity raised an initial high suspicion of malignancy, thus representing a significant diagnostic challenge, especially in the context of a patient with ulcerative colitis. The histopathological examination of the excised nodule revealed chronic infiltrates and necrosis without granuloma formation or evidence of malignancy or specific infection, mirroring findings in similar cases [7,12]. Such findings echo those reported by Galindo Pedraza et al (2023), where interstitial lung disease presented in an ulcerative colitis patient without granuloma formation, emphasizing the diagnostic ambiguity in such cases and the importance of considering a wide differential diagnosis [13].

The diagnostic process in the present case encapsulates the multifaceted challenges in identifying the nature of pulmonary nodules, particularly in patients with systemic autoimmune disorders. Initially, the lack of symptom resolution following antibiotic treatment and the discovery of multiple bilateral lung nodules on imaging necessitated a more comprehensive investigation. The avidity observed in the PET scan suggested high metabolic activity, a common indicator of malignancy or infection, yet these possibilities were not supported by subsequent histopathological findings. The differential diagnosis extended to conditions such as granulomatosis with polyangiitis and sarcoidosis [5,1]. The absence of malignancy, infection (including tuberculosis), and the characteristic granulomatous inflammation found in sarcoidosis ultimately positioned necrobiotic nodules as a diagnosis of exclusion in this complex clinical scenario [14].

To further refine the differential diagnosis, particularly in excluding rheumatological conditions that might mimic or coexist with IBD-related pulmonary manifestations, measurements of rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies are generally utilized. Nevertheless, the decision against these measurements was multifactorial: the patient’s clinical presentation did not strongly suggest a rheumatological disorder; the leading differential consideration was metastatic lung cancer, given the patient presentation and the significant PET scan avidity; and histopathology was indicative of IBD-related pathology rather than rheumatological disease. While rheumatoid factor and anti-CCP antibodies offer valuable information, in this scenario, their measurement was not immediately germane to the presentation. However, such tests could be utilized if required to exclude rheumatoid arthritis or other autoimmune diseases in more complex cases [15].

The treatment option for this type of presentation is usually immunomodulatory agents such as prednisolone and mesalazine [16,17]. However, in this case, the utilization of uniportal VATS represented a significant shift from the usual medical management strategies for necrobiotic pulmonary nodules [10]. VATS was primarily chosen to address the diagnostic ambiguity surrounding the nature of the patient’s lung nodules, particularly to exclude possibilities like malignancy, infectious emboli, or inflammatory conditions like granulomatosis with polyangiitis and sarcoidosis [5]. This surgical method not only provided crucial histopathological insights but also significantly improved the patient’s clinical condition, demonstrating the viability of surgical intervention in such cases.

The choice of VATS was further influenced by its minimally invasive nature, offering distinct advantages over more traditional surgical approaches. These advantages include reduced postoperative discomfort, shorter hospitalization, and quicker recovery, which are particularly beneficial for the management of chronic conditions like ulcerative colitis. The procedure’s success in removing the largest nodule and alleviating symptoms such as persistent cough, while reducing infection risks, exemplifies the strategic value of VATS. This highlights the importance of a customized, multidisciplinary treatment plan in managing complex cases of necrobiotic pulmonary nodules in ulcerative colitis patients.

Following the removal of the nodule from the left lower lobe, in the immediate postoperative and follow-up periods, the patient reported significant improvement in her cough symptoms. While it is recognized that such nodules are unlikely to be the sole cause of cough in this case, the symptom improvement post-resection suggests a contributory role. This observation aligns with the multifactorial nature of cough in these patients, where both pulmonary and extrapulmonary factors may interplay [18]. This underscores the importance of a comprehensive evaluation and management strategy in addressing respiratory symptoms in IBD.

In this case, a postoperative CT scan was not performed following the patient’s surgery. The consensus among the multidisciplinary team was that clinical observation would be adequate for monitoring the patient’s recovery at this stage, reserving further imaging for any arising concerns. This decision was influenced by the patient’s notable clinical improvement, the non-cancerous nature of the lesion, and the absence of new symptoms post-surgery.

The successful surgical intervention in our case contributes to the evolving narrative on necrobiotic nodules in ulcerative colitis. It underscores the importance of considering surgical options, especially in complex cases where minimally invasive interventions and medical therapy alone may not suffice. Our experience suggests that a multidisciplinary approach, involving gastroenterologists, pulmonologists, and thoracic surgeons, is critical for optimal patient outcomes. Further research is needed to better understand the indications and outcomes of surgical interventions in this context, which would contribute significantly to the scarce literature on this subject.

Conclusions

In conclusion, the diagnosis of necrobiotic pulmonary nodules represents a formidable challenge in clinical practice, largely attributable to their rarity and the limited number of documented cases in the medical literature, with only 7 instances reported thus far. Compounding this difficulty is their clinical and radiological similarity to various autoimmune and infectious conditions, which often leads to diagnostic ambiguity. This case study underscores the utility of VATS as a diagnostic tool that is minimally invasive in the management of necrobiotic pulmonary nodules.