Computed tomography (CT) findings in 88 neurofibromatosis 1 (NF1) patients: Prevalence rates and correlations of thoracic findings

[Differential diagnosis of cystic and nodular lung diseases]

BACKGROUND

Cystic and nodular lung diseases encompass a broad spectrum of diseases with different etiologies and clinicoradiological presentations. Their differentiation is crucial for patient management but can be complex due to diseases with features of both categories and overlapping radiological patterns.

OBJECTIVE

This study aims to describe the imaging features of cystic and nodular lung diseases in high-resolution computed tomography (CT) in detail-primarily based on their etiology-in order to allow a more accurate differential diagnosis of these diseases.

MATERIALS AND METHODS

A narrative review based on current literature on the topic was conducted from a clinicoradiological perspective.

RESULTS

This paper systematically categorizes the differential diagnosis of cystic and nodular lung disease and provides insights into their radiological patterns and etiologies. It highlights the role of CT in the diagnosis of these diseases and emphasizes the importance of multidisciplinary panels combining expertise from radiology, pulmonology, rheumatology, and pathology.

CONCLUSION

Reliable differential diagnosis of cystic and nodular lung diseases, particularly based on their radiological features alone, remains difficult due to their overlapping and dynamic nature. Multidisciplinary boards should be the clinical standard for accurate work-up of these diseases, as they combine the medical history, symptoms, radiological findings, and, if necessary, histopathological examinations, thus providing a more robust framework for diagnosis and management.

Neurofibromatosis type 1 and pneumoconiosis: A case report on a coincidence

Neurofibromatosis (NF) is a neurocutaneous syndrome characterized by the development of central or peripheral nervous system tumors. The most common form, known as NF1 or Von Recklinghausen's disease, presents with distinct clinical features, including cutaneous and ocular manifestations, along with various other organ and systemic symptoms. While the lung findings associated with neurofibromatosis lack specificity, they can include parenchymal cysts and bullae formation, primarily in the upper-apical regions. Additionally, progressive fibrotic changes, such as ground-glass areas, consolidations, and paving stone patterns, may manifest in the basal parts of the lungs. In this case report, a case of NF1 diagnosed in adulthood and accompanying pneumoconiosis was discussed as a coincidence.

Hemorrhagic shock due to ruptured lower limb vascular malformation in a neurofibromatosis type 1 patient: A case report

BACKGROUND

Neurofibromatosis type 1 (NF-1) is a common autosomal dominant genetic disorder. It is characterized by café-au-lait spots and cutaneous neurofibromas. Although NF-1 typically involves the skin, nerves, bones, and eyes, vascular manifestation in the form of devastating hemorrhage can occur rarely.

CASE SUMMARY

We present the case of a 47-year-old female with NF-1 who had a ruptured right lower limb arterial malformation. She presented with sudden right lower limb swelling for two hours and symptoms of hemorrhagic shock on admission. The physical examination revealed a right lower limb presenting as elephantiasis and visible dark-brown pigmentation over a large area. Computed tomography angiography showed right lower limb arteriovenous malformation. Therefore, the patient underwent emergency right lower limb digital subtraction angiography (DSA) and vascular embolization after blood transfusions. However, after DSA, vascular embolization, and repeated blood transfusions, the anemia and right lower limb swelling and tenderness did not improve. As a result, the patient underwent right lower extremity above-knee amputation. After amputation, the patient's hemoglobin level improved significantly without blood transfusion, and she was discharged from the hospital after the incision healed. Postoperative pathological examination suggested neurogenic tumors. No other complications had occurred 1-year follow-up.

CONCLUSION

Vascular malformation and rupture are fatal complications of NF-1. Embolization may not provide complete relief, the patient might need to undergo neurofibroma resection or amputation.

Intranodal Neurofibroma: A Case Report and Literature Review

PURPOSE

To report a case of neurofibroma involving the lymph nodes and to perform a literature review on this topic.

OBSERVATIONS

A 72-year-old woman with a history of neurofibromatosis and biopsy-proven malignant melanoma of the left forearm underwent wide local excision of the malignant lesion along with sentinel axillary lymph node biopsy. Histological examination of axillary nodes revealed diffuse neurofibromatosis within 2 lymph node capsules. A thorough review of the English literature pertaining to intranodal neurofibroma was performed by querying Google Scholar and PubMed. Only 5 cases of intranodal neurofibroma have been described until now.

CONCLUSIONS AND IMPORTANCE

Neurofibroma involving the lymph nodes is rare and this is the first reported case that is shown to diffusely involve the intracapsular space. Furthermore, intranodal neurofibroma can represent a diagnostic pitfall in the evaluation of sentinel lymph nodes for metastatic melanoma.

Pictorial review of computed tomography features of diffuse cystic lung disease

Diffuse cystic lung disease represents a diverse group of uncommon disorders that has been increasingly diagnosed due to the increasing use of computed tomography. It poses a frequent diagnostic challenge to radiologists due to the similar clinical and radiological features these diseases share. This pictorial review includes selected cases from the Hospital Authority New Territories West Cluster (NTWC) in Hong Kong from the past 3 years. It will illustrate the spectrum of diffuse cystic lung diseases, including some rarer entities in our locality, and identify the pertinent differentiating imaging features on CT. A flowchart to summarize these features is provided at the end to aid in diagnosis.

Neurofibromatosis type 1: evaluation by chest computed tomography

Objective

The aim of this study was to evaluate chest computed tomography (CT) findings in patients diagnosed with neurofibromatosis type 1 (NF1).

Material and Methods

This was a retrospective study in which we reviewed the chest CT scans of 14 patients diagnosed with NF1 and neurofibromatosis-associated diffuse lung disease (NF-DLD). The sample comprised eight women and six men. The median age was 55 years (range, 11-75 years). The diagnosis of NF1 was made on the basis of the diagnostic criteria established by the U.S. National Institutes of Health. The images were analyzed by two chest radiologists, who reached decisions by consensus.

Results

The predominant CT finding of NF-DLD was multiple cysts, which were observed in 13 patients (92.9%), followed by emphysema, in eight (57.1%) and subpleural bullae, in six (42.9%). Other findings included subcutaneous neurofibromas, in 12 patients (85.7%), ground-glass opacities, in one (7.1%), and tracheobronchial neurofibromas, in one (7.1%). The pulmonary abnormalities were bilateral in 12 cases (85.7%). The abnormalities were predominantly in the upper lung fields in eight cases (57.1%), and their distribution was random in 11 (78.6%).

Conclusion

Pulmonary cysts, emphysema, and subpleural bullae appear to be the chest CT findings that are most characteristic of NF-DLD.

Imaging of the rare cystic lung diseases

When discussing cystic lung diseases, a certain group of diseases tends to receive the majority of attention. Other less frequently discussed cystic lung diseases are also important causes of morbidity in patients. Etiologies include genetic syndromes, lymphoproliferative diseases, infections, exogenous exposures, and a developmental abnormality. This review article focuses on the clinical and imaging features of these other cystic lung diseases.

Structural alteration of lung parenchyma in patients with NF1: a phenotyping study using multidetector computed tomography (MDCT)

BACKGROUND

Diffuse interstitial lung disease have been described in Neurofibromatosis type 1 (NF1), but its diversity and prevalence remain unknown. The aim of this study was to assess the prevalence and characteristics of (NF1)-associated lung manifestations in a large single-center study using multidetector computed tomography (MDCT) and to evaluate the smoking history, patients' age, genetics, and the presence of malignant peripheral nerve sheath tumors (MPNST) as potential influencing factors for lung pathologies.

METHODS

In this retrospective study, 71 patients with NF1 were evaluated for the presence of distinctive lung manifestations like reticulations, consolidations, type of emphysema, pulmonary nodules and cysts. All patients underwent F-18-FDG PET/CT scans, which were reviewed by two experienced radiologists in consensus. Patients' subgroups were formed based on their smoking history (current smokers/previous smokers/never smokers), age (< 12 years, 12-18 years, > 18 years), and presence of MPNST (MPNST/no MPNST). In 57 patients (80%), genetic analysis of sequences coding for the neurofibromin on chromosome 17 was performed, which was correlated with different lung pathologies.

RESULTS

Among all NF1 patients (33 ± 14 years, 56% females), 17 patients (24%) were current smokers and 62 patients (87%) were > 18 years old. Pulmonary cysts, nodules, and paraseptal emphysema were the most common pulmonary findings (35%, 32%, 30%). The presence of pulmonary metastases, MPNST and centrilobular emphysema was associated with smoking. Cysts were observed only in adults, whereas no significant correlation between age and all other pulmonary findings was found (p > 0.05). Presence of MPNST was accompanied by higher rates of intrapulmonary nodules and pulmonary metastasis. Neither the presence nor absence of any of the specific gene mutations was associated with any particular lung pathology (p > 0.05).

CONCLUSIONS

All pulmonary findings in NF1 patients occurred independently from specific mutation subtypes, suggesting that many NF1 mutations can cause various pulmonary pathologies. The presence of pulmonary metastases, MPNST and centrilobular emphysema was associated with smoking, indicating the value of smoking secession or the advice not to start smoking in NF1 patients as preventive strategy for clinicians. For screening of pulmonary manifestations in NF1 patients, an MDCT besides medical history and physical examination is mandatory in clinical routine.

Phenotype and Outcomes of Pulmonary Hypertension Associated with Neurofibromatosis Type 1

Rationale: Pulmonary hypertension (PH) associated with neurofibromatosis type 1 (NF1) is a rare and largely unknown complication of NF1.Objectives: To describe characteristics and outcomes of PH-NF1.Methods: We reported the clinical, functional, radiologic, histologic, and hemodynamic characteristics, response to pulmonary arterial hypertension (PAH)-approved drugs, and transplant-free survival of patients with PH-NF1 from the French PH registry.Measurements and Main Results: We identified 49 PH-NF1 cases, characterized by a female/male ratio of 3.9 and a median (minimum-maximum) age at diagnosis of 62 (18-82) years. At diagnosis, 92% were in New York Heart Association functional class III or IV. The 6-minute-walk distance was 211 (0-460) m. Pulmonary function tests showed low Dl_CO (30% [12-79%]) and severe hypoxemia (Pa_O2 56 [38-99] mm Hg). Right heart catheterization showed severe precapillary PH with a mean pulmonary artery pressure of 45 (10) mm Hg and a pulmonary vascular resistance of 10.7 (4.2) Wood units. High-resolution computed tomography images revealed cysts (76%), ground-glass opacities (73%), emphysema (49%), and reticulations (39%). Forty patients received PAH-approved drugs with a significant improvement in functional class and hemodynamic parameters. Transplant-free survival at 1, 3, and 5 years was 87%, 54%, and 42%, respectively, and four patients were transplanted. Pathologic assessment showed nonspecific interstitial pneumonia and major pulmonary vascular remodeling.Conclusions: PH-NF1 is characterized by a female predominance, a low Dl_CO, and severe functional and hemodynamic impairment. Despite a potential benefit of PAH treatment, prognosis remains poor, and double-lung transplantation is an option for eligible patients.

Clinical characterization of children and adolescents with NF1 microdeletions

PURPOSE

An estimated 5-11% of patients with neurofibromatosis type 1 (NF1) harbour NF1 microdeletions encompassing the NF1 gene and its flanking regions. The purpose of this study was to evaluate the clinical phenotype in children and adolescents with NF1 microdeletions.

METHODS

We retrospectively analysed 30 children and adolescents with NF1 microdeletions pertaining to externally visible neurofibromas. The internal tumour load was determined by volumetry of whole-body magnetic resonance imaging (MRI) in 20 children and adolescents with NF1 microdeletions. Furthermore, the prevalence of global developmental delay, autism spectrum disorder and attention deficit hyperactivity disorder (ADHD) were evaluated.

RESULTS

Children and adolescents with NF1 microdeletions had significantly more often cutaneous, subcutaneous and externally visible plexiform neurofibromas than age-matched patients with intragenic NF1 mutations. Internal neurofibromas were detected in all 20 children and adolescents with NF1 microdeletions analysed by whole-body MRI. By contrast, only 17 (61%) of 28 age-matched NF1 patients without microdeletions had internal tumours. The total internal tumour load was significantly higher in NF1 microdeletion patients than in NF1 patients without microdeletions. Global developmental delay was observed in 28 (93%) of 30 children with NF1 microdeletions investigated. The mean full-scale intelligence quotient in our patient group was 77.7 which is significantly lower than that of patients with intragenic NF1 mutations. ADHD was diagnosed in 15 (88%) of 17 children and adolescents with NF1 microdeletion. Furthermore, 17 (71%) of the 24 patients investigated had T-scores ≥ 60 up to 75, indicative of mild to moderate autistic symptoms, which are consequently significantly more frequent in patients with NF1 microdeletions than in the general NF1 population. Also, the mean total T-score was significantly higher in patients with NF1 microdeletions than in the general NF1 population.

CONCLUSION

Our findings indicate that already at a very young age, NF1 microdeletions patients frequently exhibit a severe disease manifestation which requires specialized long-term clinical care.

Phenotypic heterogeneity of neurofibromatosis type 1 in a large international registry

Neurofibromatosis type 1 (NF1) is a rare genetic disorder, characterized by the development of benign and malignant nerve tumors. Although all individuals with NF1 harbor genetic alterations in the same gene, the clinical manifestations of NF1 are extremely heterogeneous even among individuals who carry identical genetic defects. In order to deepen the understanding of phenotypic manifestations in NF1, we comprehensively characterized the prevalence of 18 phenotypic traits in 2051 adults with NF1 from the Children's Tumor Foundation's NF1 registry. We further investigated the coassociation of traits and found positive correlations between spinal neurofibromas and pain, spinal neurofibromas and scoliosis, spinal neurofibromas and optic gliomas, and optic gliomas and sphenoid wing dysplasia. Furthermore, with increasing numbers of cutaneous neurofibromas, the odds ratio of malignant peripheral nerve sheath tumor increased. Phenotypic clustering revealed 6 phenotypic patient cluster subtypes: mild, freckling predominant, neurofibroma predominant, skeletal predominant, late-onset neural severe, and early-onset neural severe, highlighting potential phenotypic subtypes within NF1. Together, our results support potential shared molecular pathogenesis for certain clinical manifestations and illustrate the utility of disease registries for understanding rare diseases.

Neurofibromatosis-Associated Diffuse Lung Disease: A Case Report and Review of the Literature

Neurofibromatosis-1 or von Recklinghausen’s disease is an autosomal dominant disorder. Cafe au lait macules are generally the initial presenting feature of the disease, and there can be varying degrees of involvement of the skeletal, neurological, and pulmonary organ systems as the disease progresses.

The existence of neurofibromatosis-associated diffuse lung disease (NF-DLD) as a separate entity has always been questioned and, is often attributed to cigarette smoking, rather than a manifestation of NF-1.

A 59-year-old male with a history of neurofibromatosis presented with shortness of breath and ataxia for 10 days. Exam findings were pertinent for tachycardia, tachypnea, and diffuse cutaneous neurofibromas. Workup showed white blood count (WBC) of 15.9 k/ul, electrocardiogram with biatrial enlargement and right axis deviation, and a chest X-ray showed left lower lobe infiltrate concerning for pneumonia. Computed tomography (CT) scan of the chest revealed left basilar consolidation with surrounding ground-glass opacities and innumerable bilateral thin-walled cysts. The latter finding raised suspicion for NF-DLD.

The patient was evaluated by pulmonology with recommendations to continue treatment for pneumonia and follow-up with high-resolution CT of the chest and complete pulmonary function testing in 12 weeks. He was discharged in a stable condition after five days of hospitalization.

NF-DLD is a pulmonary manifestation of NF-1 with non-specific respiratory symptoms and a characteristic pattern of upper lobe cystic and basilar interstitial lung disease. It usually presents in the 4th or 5th decade, earlier in tobacco users, but a few pediatric cases have also been reported.

The presentation of NF-DLD can be variable, ranging from dyspnea, chest pain, chronic cough, hemoptysis, or an incidental finding on CT. Multiple complications, including spontaneous pneumothorax due to the rupture of subpleural blebs, pulmonary hypertension, and chronic respiratory failure, are associated with NF-DLD.

NF-DLD can be prevented by smoking cessation but, there are no known modalities for treatment; however, complications can be managed symptomatically.

This case illustrates the diagnostic challenge that NF-DLD represents to clinicians. The patient's CT from two years ago showed emphysematous changes along with scattered fibrosis and scarring, and no cystic changes were mentioned, unlike his latest CT, which showed innumerable cysts. This patient had a history of smoking, which likely put him at a higher risk for the development of cysts. However, he quit smoking 10 years prior, which suggests that his lung changes are not secondary to cigarette smoke, further confirming our suspicion for NF-DLD. Although routine screening is not implemented due to the rarity of the disease, NF-DLD should not be ruled out in patients with NF-1 presenting with pulmonary symptoms until a high-resolution computed tomography (HRCT) is obtained.

Longitudinal phenotype development in a minipig model of neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a rare, autosomal dominant disease with variable clinical presentations. Large animal models are useful to help dissect molecular mechanisms, determine relevant biomarkers, and develop effective therapeutics. Here, we studied a NF1 minipig model (NF1+/ex42del) for the first 12 months of life to evaluate phenotype development, track disease progression, and provide a comparison to human subjects. Through systematic evaluation, we have shown that compared to littermate controls, the NF1 model develops phenotypic characteristics of human NF1: [1] café-au-lait macules, [2] axillary/inguinal freckling, [3] shortened stature, [4] tibial bone curvature, and [5] neurofibroma. At 4 months, full body computed tomography imaging detected significantly smaller long bones in NF1+/ex42del minipigs compared to controls, indicative of shorter stature. We found quantitative evidence of tibial bowing in a subpopulation of NF1 minipigs. By 8 months, an NF1+/ex42del boar developed a large diffuse shoulder neurofibroma, visualized on magnetic resonance imaging, which subsequently grew in size and depth as the animal aged up to 20 months. The NF1+/ex42del minipig model progressively demonstrates signature attributes that parallel clinical manifestations seen in humans and provides a viable tool for future translational NF1 research.

Neurofibromatosis type-1-associated diffuse lung disease in children

OBJECTIVE

The purpose of the study was to investigate the occurrence of diffuse lung disease associated with neurofibromatosis type-1 in the pediatric population. We also aimed at evaluating computed tomography (CT) findings of the disease.

INTRODUCTION

Diffuse lung disease associated with neurofibromatosis type-1 has been described mainly in the adult population; causes and connections between lung disease and the genetic disorder are still not completely understood. The occurrence of the disease in non-smokers, the presence of blebs, bullae or cysts distinct from smoking-related emphysema on CT and the histopathological pattern characterized by lymphoplasmocytic inflammation and fibrosis, are all factors that support the association of diffuse lung disease as a distinct manifestation of neurofibromatosis.

METHODS

We retrospectively reviewed, with "lung window," all the spinal CTs performed in two institutions from 2004 to 2018 for scoliosis assessment in pediatric patients affected by neurofibromatosis type-1 (group 1). Moreover, we retrospectively analyzed a control group of pediatric patients, affected by severe scoliosis without neurofibromatosis (group 2). Differences between the two groups were analyzed to ascertain whether the disease can be related to neurofibromatosis type-1 rather than to scoliosis.

RESULTS

Six out of thirty one subjects from group 1 (19.4%) showed a condition of diffuse lung disease while none (0 of 31) in group 2. The differences between the two groups were statistically significant (P = .01). All six patients showed subpleural blebs, bullae, or cysts without basilar fibrosis.

CONCLUSION

Our research consolidates the hypothesis that diffuse lung disease is a direct manifestation of neurofibromatosis type-1 and that early onset is possible, even in pediatric patients.

Neurofibromatosis type 1: State-of-the-art review with emphasis on pulmonary involvement

Neurofibromatosis type 1 (NF-1), also known as von Recklinghausen's disease, is an autosomal dominant dysplasia of the ectoderm and mesoderm with a variable clinical expression, but near-complete penetrance before the age of 5 years. The estimated incidence is 1 in 3000 births. NF-1 is characterized by collections of neurofibromas, café-au-lait spots, axillary and inguinal freckling, and pigmented hamartomas in the iris (Lisch nodules). Pulmonary manifestations of NF-1, which usually include bilateral basal reticulations and apical bullae and cysts, are reported in 10-20% of adult patients. Clinically, neurofibromatosis-associated diffuse lung disease (NF-DLD) usually presents with nonspecific respiratory symptoms, including dyspnea on exertion, shortness of breath, and chronic cough or chest pain, at the time of diagnosis. Computed tomography (CT) is highly accurate for the identification and characterization of NF-DLD; it is the most reliable method for the diagnosis of this lung involvement. Various CT findings of NF-DLD, including cysts, bullae, ground-glass opacities, bibasilar reticular opacities, and emphysema, have been described in patients with NF-1. The typical CT pattern, however, is characterized by upper-lobe cystic and bullous disease, and basilar interstitial lung disease. Currently, the goal of NF-DLD treatment is the earliest possible diagnosis, focusing on symptom relief and interventions that positively alter the course of the disease, such as smoking cessation. The aim of this review is to describe the main clinical, pathological, and imaging aspects of NF-1, with a focus on pulmonary involvement.

Cystic Lung Diseases: Algorithmic Approach

Cysts are commonly seen on CT scans of the lungs, and diagnosis can be challenging. Clinical and radiographic features combined with a multidisciplinary approach may help differentiate among various disease entities, allowing correct diagnosis. It is important to distinguish cysts from cavities because they each have distinct etiologies and associated clinical disorders. Conditions such as emphysema, and cystic bronchiectasis may also mimic cystic disease. A simplified classification of cysts is proposed. Cysts can occur in greater profusion in the subpleural areas, when they typically represent paraseptal emphysema, bullae, or honeycombing. Cysts that are present in the lung parenchyma but away from subpleural areas may be present without any other abnormalities on high-resolution CT scans. These are further categorized into solitary or multifocal/diffuse cysts. Solitary cysts may be incidentally discovered and may be an age related phenomenon or may be a remnant of prior trauma or infection. Multifocal/diffuse cysts can occur with lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, tracheobronchial papillomatosis, or primary and metastatic cancers. Multifocal/diffuse cysts may be associated with nodules (lymphoid interstitial pneumonia, light-chain deposition disease, amyloidosis, and Langerhans cell histiocytosis) or with ground-glass opacities (Pneumocystis jirovecii pneumonia and desquamative interstitial pneumonia). Using the results of the high-resolution CT scans as a starting point, and incorporating the patient's clinical history, physical examination, and laboratory findings, is likely to narrow the differential diagnosis of cystic lesions considerably.