Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH) and the Role of Somatostatin analogs: A Case Series

Pulmonary Function Tests as a Biomarker in Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia Patients Treated With Somatostatin Analogues

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) describes an indolent, under-recognised and poorly understood pulmonary condition with fewer than 200 reported cases across the literature. Currently, cases are diagnosed following a biopsy of the primary lesion, with treatment options centring on symptomatic benefit as opposed to targeting the underlying aetiology. Classically, DIPNECH lesions have been described as slow growing and benign, but with growing awareness of the condition, reports of metastatic disease with significant symptomatic burden have been reported. However, effectively addressing the subset of DIPNECH patients with greater metastatic potential remains an unmet clinical need. Due to the similarities between DIPNECH and carcinoid patients, several centres have considered using somatostatin analogues to not only help symptomatically but also to initiate tumour regression. However, to date, there are limited biomarkers to help evaluate the benefit of such options. In this review, we consider the use of pulmonary function tests (PFTs) to help quantify the benefit of somatostatin analogues. Although much of the evidence stems from small single-centre studies, the use of PFTs within the treatment pathway for both localised and metastatic DIPNECH represents a meaningful improvement from subjective monitoring of disease.

De-labeling severe asthma diagnosis: the challenge of DIPNECH

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disease characterised by neuroendocrine cell hyperplasia within the bronchial epithelium [1]. The clinical presentation is characterised by nonspecific respiratory symptoms such as chronic cough, dyspnoea and bronchospasm. Given the rarity of the disease and the low specificity of symptoms, the diagnosis of DIPNECH is challenging and the time between symptom onset and diagnosis is long [1]. DIPNECH comprises a generalised proliferation of scattered neuroendocrine cells, small nodules (neuroendocrine bodies) or a linear proliferation of pulmonary neuroendocrine cells. It has been suggested that DIPNECH may mimic [2] or precede [3] asthma. The role of products of neuroendocrine cells such as substance P, which contribute to eosinophil migration, has been suggested to explain asthma symptoms in DIPNECH [3]. However, the characteristics of patients with DIPNECH who have symptoms suggestive of asthma have never been described. The aim of our study was to determine whether patients diagnosed with DIPNECH and initially referred for severe asthma management had specific characteristics.

DIPNECH is a differential diagnosis of severe asthma with no specific biomarkers. Chronic cough and multiple nodules on CT should prompt clinicians to consider this diagnosis. Differentiating DIPNECH from severe asthma remains crucial.https://bit.ly/3mmFbQn

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: clinical characteristics and progression to carcinoid tumour

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is considered a preinvasive lesion that may progress to carcinoid tumour [1]. Histologically, it is marked by a proliferation of neuroendocrine cells that is confined to the basement membrane (neuroendocrine cell hyperplasia; NECH), and/or has invaded past the basement membrane (carcinoid tumourlet) [2]. Tumourlets equal to or larger than 5 mm are classified as carcinoid tumours. Per the World Health Organization 2021 criteria, DIPNECH can be pathological (based solely on characteristic histological features) or clinical (diagnosed per characteristic symptoms and imaging findings, e.g. respiratory symptoms, bilateral pulmonary nodules, mosaic attenuation on computed tomography (CT)) [2]. In contrast to some lung diseases or neoplasms that can cause secondary, reactive NECH/tumourlets to form, DIPNECH is marked by such hyperplasia without an identifiable cause.

DIPNECH is a rare disease that is often misdiagnosed. In this study, it primarily affected elderly white women who were non-smokers. Lung nodules could slowly progress over years to carcinoid tumours. Average growth rate per nodule was 0.8 mm per year.https://bit.ly/3q1HD1k

A 75-Year-Old Woman With Pulmonary Nodules and Dyspnea

CASE PRESENTATION

A 75-year-old woman was referred to the pulmonary office in January 2020 for cough and progressive worsening of shortness of breath over the years. Her medical history was significant for asthma that was diagnosed approximately 10 years earlier, when she first developed dyspnea. A pre-bronchodilator spirometry at that time showed severe airflow obstruction (Fig 1). The patient was incidentally found to have several noncalcified pulmonary nodules on a chest CT scan in 2015, which was obtained as a part of dyspnea workup. She underwent bronchoscopic evaluation with transbronchial biopsy of the largest nodule (1.6 × 1.2 cm) in the right middle lobe. She was diagnosed with low-grade neuroendocrine tumor (typical carcinoid) and had been under surveillance without any progression in the number of nodules or the size of the existing nodules. She was a lifelong nonsmoker and no family history of asthma. Over the years, she received multiple courses of systemic corticosteroids and different inhalers, without any improvement in her symptoms. The patient was frustrated by the lack of perceived benefit, and she discontinued all respiratory medications. She denied any fever, night sweats, exertional chest pain, or seasonal allergies but reported cough, wheezing, and severe exertional shortness of breath. She was unable to walk more than 20 feet at a time. She had no pets at home and did not travel outside the United States. Her only home medications were multivitamins and low-dose aspirin.

An Older Woman With Transient Cough, Mild Airway Obstruction, and Lung Nodules

CASE PRESENTATION

A 66-year-old woman with no significant medical history presented initially to her primary care physician's office with a 2-weeks history of productive cough and associated wheezing after cough paroxysms. Empiric antibiotic was started, with no improvement. Chest radiograph was performed, which showed bilateral nodular opacities (Fig 1). The patient's cough resolved in 6 weeks after empiric treatment with oral steroids, inhaled steroids, and bronchodilators. A follow-up chest radiograph done at 6 weeks showed persistent abnormalities, and she was referred for a pulmonary evaluation. She denied any fevers, cough, hemoptysis, shortness of breath, wheezing, loss of appetite, or weight loss at that time. She had no significant medical problems and was not on any medications at that time. She was a nonsmoker. She worked in an office setting and denied any occupational or recreational exposures or recent travels. There was no family history of lung diseases or cancer.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: DIPNECH

PURPOSE OF REVIEW

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare premalignant condition. Over the past decade, there has been increased recognition and reporting of DIPNECH in the literature. Currently, our understanding is that DIPNECH has a predilection to nonsmoking females around their sixth decade of life. The patients usually present with chronic cough, dyspnea, and computed tomography (CT) showing multifocal pulmonary nodules with associated mosaic attenuation. The clinic history is largely driven by constrictive obliterative bronchiolitis, which typically has an indolent course with progressive respiratory decline and difficult to treat symptoms.

RECENT FINDINGS

DIPNECH has been found to be associated with carcinoid tumors. Recent data has found that symptomatic DIPNECH patients respond to somatostatin analog (SSA). SSAs provide improvement in symptoms and pulmonary function tests. According to small studies and case series SSAs can be used in conjunction with steroids and bronchodilators for the treatment of respiratory symptoms.

SUMMARY

DINPNECH is a premalignant condition that can transform into carcinoid tumors. Although the recent data suggest the potential efficacy of SSA, further studies are needed to validate such results in prospective fashion in addition to investigating other therapeutic agents.

An Update on the Management of Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH)

OPINION STATEMENT

DIPNECH is caused by an idiopathic proliferation of pulmonary neuroendocrine cells which can lead to bronchiolitis and multifocal lung neuroendocrine tumors. Patients often present with chronic cough and dyspnea. Larger NETs may develop malignant potential. Somatostatin analogs can palliate chronic symptoms, particularly cough. Surgical resection can be considered for relatively large (e.g. >1 cm), progressive tumors.

Constrictive bronchiolitis in diffuse idiopathic pulmonary neuroendocrine cell hyperplasia

Background

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is characterised by multifocal proliferation of neuroendocrine cells and belongs in the spectrum of pulmonary neuroendocrine tumours. Some patients with DIPNECH develop airflow obstruction but the relationship between the two entities remains unclear.

Methods

We performed a computer-assisted search of the Mayo Clinic's electronic medical records for biopsy-proven cases of DIPNECH. We extracted clinical, pulmonary function, imaging and histopathological data along with treatments and outcomes.

Results

Among 44 patients with DIPNECH 91% were female and the median age was 65 years (interquartile range 56–69 years); 73% were never-smokers. Overall, 38 patients (86%) had respiratory symptoms including cough (68%) and dyspnoea (30%); 45% were previously diagnosed to have asthma or COPD. Pulmonary function testing showed an obstructive pattern in 52%, restrictive pattern in 11%, mixed pattern in 9%, nonspecific pattern in 23%, and was normal in 5%. On chest computed tomography scan, 95% manifested diffuse nodules and 77% manifested mosaic attenuation. For management, 25% of patients were observed without pharmacological therapy, 55% received an inhaled bronchodilator, 41% received an inhaled corticosteroid, 32% received octreotide; systemic steroids, azithromycin, or combination chemotherapy was employed in four patients (9%). Of 24 patients with available follow-up pulmonary function tests, 50% remained stable, 33% worsened and 17% improved over a median interval of 21.3 months (interquartile range 9.7–46.9 months).

Conclusion

DIPNECH occurs mostly in women and manifests diffuse pulmonary nodules and mosaic attenuation on imaging. It is commonly associated with airflow obstruction due to constrictive bronchiolitis, which manifests limited response to current pharmacological therapy.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an under-recognised cause of obstructive lung disease in women. Constrictive bronchiolitis associated with DIPNECH manifests limited response to currently employed therapies.https://bit.ly/3c3RZoe

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Imaging and Clinical Features of a Frequently Delayed Diagnosis

OBJECTIVE. The purpose of this study was to assess features of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) on CT, clinical presentation, and delays in radiologic and clinical diagnosis in a series of 32 patients. MATERIALS AND METHODS. Medical records of patients with DIPNECH from the years 2000-2017 were obtained from an institutional data warehouse. Inclusion criteria were an available CT examination and either a pathologic diagnosis of DIPNECH or pathologic findings of multiple carcinoid tumorlets or carcinoid tumor with CT features suggesting DIPNECH. Two thoracic radiologists with 10 and 14 years of experience reviewed CT examinations and scored cases in consensus. RESULTS. All 32 patients were women, and most had never smoked (69%). The mean age at presentation was 61 years. Symptoms included chronic cough (59%) or dyspnea (28%), and the initial clinical diagnosis was asthma in 41%. DIPNECH was clinically suspected at presentation in only one case and was mentioned by the interpreting radiologist in only 31% of cases. CT characteristics included numerous nodules with a lower zone and peribronchiolar predominance, mosaic attenuation, and nodular bronchial wall thickening. Number of nodules at least 5 mm in diameter showed strong inverse correlations with the percentage predicted for both forced vital capacity and forced expiratory volume in 1 second and a moderate inverse correlation with total lung capacity percentage predicted. In cases with a follow-up CT interval of 3 years or longer, 85% of patients showed an increase in size of the largest nodule, and 70% had an increase in size in multiple nodules. CONCLUSION. Many cases of DIPNECH are originally missed or misdiagnosed by radiologists and clinicians. Awareness of the typical clinical and imaging features of DIPNECH may prompt earlier diagnosis of this condition.

Somatostatin Analogs Improve Respiratory Symptoms in Patients With Diffuse Idiopathic Neuroendocrine Cell Hyperplasia

BACKGROUND

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare lung disease associated with proliferation of neuroendocrine cells in the lung and multifocal neuroendocrine tumorlets/tumors. Although usually considered an indolent condition, DIPNECH causes chronic, progressive cough and dyspnea which can adversely impact quality of life. There is very limited information on the treatment of this condition. The objective of this study was to assess changes in symptoms and pulmonary function tests (PFTs) in response to somatostatin analog (SSA) treatment.

METHODS

Patients with clinical and/or pathologic diagnosis of DIPNECH and chronic respiratory symptoms were treated with SSAs at the H. Lee Moffitt Cancer Center and Research Institute, Hadassah-Hebrew University Medical Center, and Mayo Clinic Cancer Center. Their charts were reviewed to assess changes in symptoms and PFTs.

RESULTS

Forty-two patients were identified who had either chronic cough or dyspnea because of proven or suspected DIPNECH and who had received treatment with an SSA. Thirty-three patients experienced symptomatic improvement. Additionally, 14 of 15 patients in whom PFTs were checked were noted to have an improvement in FEV₁ after treatment.

CONCLUSIONS

SSA treatment can improve chronic respiratory symptoms and PFTs in patients with DIPNECH.

[A case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) syndrome]

INTRODUCTION

DIPNECH is a strictly histological entity according to the WHO 2015 classification and is considered to be at pre-neoplastic risk. It has been proposed that DIPNECH syndrome should be used to describe patients have clinical symptoms, an obstructive ventilatory disorder and compatible radiological abnormalities. The diagnosis is histological and usually based on a surgical lung biopsy.

CASE REPORT

We report the case of a 58-year-old woman with a chronic cough for over 20years who had an obstructive airway pattern on spirometry. Diagnoses of asthma and COPD had been discussed. After 7years of follow-up, the DIPNECH hypothesis was evoked on the scanning aspect of mosaic attenuation, expiratory trapping and micronodules, which was subsequently confirmed by surgical pulmonary biopsy.

CONCLUSION

It is necessary to consider the possibility of this rare disease in order to avoid inappropriate treatments and in the hope that future therapeutic advances (somatostatin analogs, mTOR inhibitors) improve patients' experience and the progression of respiratory function.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia in a young man with hypoxia: a case report and review of the literature

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare lung disease, which usually affects older women. This disease is often asymptomatic. For patients who are symptomatic, symptoms usually include cough and dyspnea. In this paper, we reported a 38-year-old man who suffered from chest pain for 3 months. CT scan findings revealed scattered nodules that were less than 1 cm. Spirometry was normal and the arterial oxygen saturation at room air was 85%. Open lung biopsy revealed DIPNECH. Patients with DIPNECH are mainly elderly women with symptoms including cough and dyspnea. However, we reported a young man with chest pain and hypoxia without dyspnea. DIPNECH can occur in male and female individuals at any age. (www.actabiomedica.it)

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Review of the Literature and a Single-center Experience

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare disorder that is commonly underdiagnosed. In 2015, it was recognized by the World Health Organization (WHO) classification of lung tumors as a premalignant lesion. DIPNECH syndrome is characterized by cough, exertional dyspnea, wheezing, and, less frequently, hemoptysis. We report the clinical and histological features and imaging findings in four cases of DIPNECH from our institution (Torrejon University Hospital, Madrid, Spain) between the years 2012 and 2019. DIPNECH represents a rare and poorly understood pulmonary disorder. Our limited single-center experience shows the slow and stable evolution of the disease. However, some exceptional cases may progress poorly if distant metastases occur.

Diffuse idiopathic neuroendocrine cell hyperplasia as a rare cause of chronic cough

A 39-year-old Caucasian woman, who has never smoked, presented a 16-year-duration chronic dry cough. She was prescribed by her general physician with corticosteroid and long-acting β-agonist inhalers assuming it was asthma, with mild symptomatic improvement. When cough got more persistent and associated with exertional dyspnoea and wheezing, a chest CT scan was performed, which showed multiple bilateral micronodular formations and diffuse mosaic lung pattern with air trapping. She was sent to our Respiratory Department and performed a bronchoalveolar lavage and cryobiopsy that were inconclusive. She underwent surgical lung biopsy with pathology revealing multiple foci of neuroendocrine cell hyperplasia and tumourlets associated with constrictive bronchiolitis, a histological pattern suggestive of diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH). DIPNECH is a rare and preinvasive disease. Presenting symptoms can be cough and breathlessness. At the time of writing, the patient is on octreotide with symptomatic improvement.

Series of rare lung diseases mimicking imaging patterns of common diffuse parenchymal lung diseases

Diffuse parenchymal lung diseases (DPLDs) encompass a variety of restrictive and obstructive lung pathologies. In this article, the authors discuss a series of rare pulmonary entities and their high-resolution computed tomography imaging appearances, which can mimic more commonly encountered patterns of DPLDs. These cases highlight the importance of surgical lung biopsies in patients with imaging findings that do not show typical imaging features of usual interstitial pneumonia.

Management of pulmonary neuroendocrine tumors

Neuroendocrine tumors (NETs) of the lung are divided into 4 major types: small cell lung cancer (SCLC), large cell neuroendocrine carcinoma (LCNEC), atypical carcinoid (AC) or typical carcinoid (TC). Each classification has distinctly different treatment paradigms, making an accurate initial diagnosis essential. The inconsistent clinical presentation of this disease, however, makes this difficult. The objective of this manuscript is to detail the diagnosis and management of the well differentiated pulmonary carcinoid (PC) tumors. A multidisciplinary approach to work up and treatment should be utilized for each patient. A multimodal radiological work-up is used for diagnosis, with contrast enhanced CT predominantly utilized and functional imaging techniques. A definitive diagnosis is based on tissue findings. Surgical management remains the mainstay of therapy and can be curative. In those with advanced disease, medical treatments consist of somatostatin analog (SSA) therapy, targeted therapy, chemotherapy or peptide receptor radionuclide therapy. SSAs are the standard of care in those with metastatic NETs, using either Octreotide long acting repeatable (LAR) or lanreotide as reasonable options, despite a scarcity of prospective data in PCs. Targeted therapies consist of everolimus which is approved for use in PCs, with various studies showing mixed results with other targeted agents. Additionally, radionuclide therapy may be used and has been shown to increase survival and to reduce symptoms in some studies. Prospective trials are needed to determine other strategies that may be beneficial in PCs as well as sequencing of therapy. Successful diagnosis and optimal treatment relies on a multidisciplinary approach in patients with lung NETs. Clinical trials should be used in appropriate patients.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia syndrome

The term diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) may be used to describe a clinico-pathological syndrome, as well as an incidental finding on histological examination, although there are obvious differences between these two scenarios. According to the World Health Organization, the definition of DIPNECH is purely histological. However, DIPNECH encompasses symptomatic patients with airway disease, as well as asymptomatic patients with neuroendocrine cell hyperplasia associated with multiple tumourlets/carcinoid tumours. DIPNECH is also considered a pre-neoplastic lesion in the spectrum of pulmonary neuroendocrine tumours, because it is commonly found in patients with peripheral carcinoid tumours.

In this review, we summarise clinical, physiological, radiological and histological features of DIPNECH and critically discuss recently proposed diagnostic criteria. In addition, we propose that the term “DIPNECH syndrome” be used to indicate a sufficiently distinct patient subgroup characterised by respiratory symptoms, airflow obstruction, mosaic attenuation with air trapping on chest imaging and constrictive obliterative bronchiolitis, often with nodular proliferation of neuroendocrine cells with/without tumourlets/carcinoid tumours on histology. Surgical lung biopsy is the diagnostic gold standard. However, in the appropriate clinical and radiological setting, transbronchial lung biopsy may also allow a confident diagnosis of DIPNECH syndrome.

Rare Occurrence of Hypergastrinemia Due to Thoracic Neuroendocrine Tumor: Detection and Characterization by 68Ga-DOTATATE PET/CT

Hypergastrinemia is a prominent feature of a segment of gastroenteropancreatic neuroendocrine tumors, the gastrinomas, occurring mostly in the gastrinoma triangle. Hypergastrinemia due to a thoracic neuroendocrine tumor is a very rare occurrence, with a paucity of literature elucidating the same. We report a case of thoracic neuroendocrine tumor in a patient who had initially presented with symptoms of peptic ulcer disease of 3-y duration. On evaluation, the patient's fasting serum gastrin levels were found to be raised. Conventional imaging modalities and endoscopic evaluation did not identify the location of a possible gastrinoma or any other mass in the abdomen. In view of the hypergastrinemia, somatostatin receptor-targeted imaging with (68)Ga-DOTATATE PET/CT was undertaken and showed a somatostatin receptor-expressing paravertebral mass next to the thoracic aorta in the left lung. The mass was excised and was histopathologically suggestive of metastatic neuroendocrine tumor (MIB-1 labeling index, 2%). The present case underscores the importance of (68)Ga-DOTATATE PET/CT in both detecting and characterizing a causative lesion missed on contrast-enhanced CT, especially when the lesion is not easily amenable to biopsy.