DIPNECH: Association Between Histopathology and Clinical Presentation

Prognostic Significance of Pulmonary Multifocal Neuroendocrine Proliferation With Typical Carcinoid

BACKGROUND

The clinical significance of multifocal pulmonary neuroendocrine proliferation (MNEP), including tumorlets and pulmonary neuroendocrine cell hyperplasia, in association with typical carcinoid (TC), is still debated.

METHODS

We evaluated a retrospective series of TC with long-term follow-up data prospectively collected from 2 institutions and compared the outcome between TC alone and MNEP plus TC. Several baseline covariates were imbalanced between the MNEP plus TC and TC groups; therefore, we conducted 1:1 propensity score matching and inverse probability of treatment weighting in the full sample. In the matched group, the association of clinical, respiratory, and work-related factors with the group was determined through univariable and multivariable conditional logistic regression analysis.

RESULTS

A total of 234 TC patients underwent surgery: 41 MNEP plus TC (17.5%) and 193 TC alone (82.5%). In the MNEP plus TC group, older age (P < .001), peripheral tumors (P = .0032), smaller tumor size (P = .011), and lymph node spread (P = .02) were observed compared with the TC group. Relapses occurred in 8 patients in the MNEP plus TC group (19.5%) and 7 in the TC group (3.6%). After matching, in 36 pairs of patients, a significantly higher 5-year progression-free rate was observed for the TC group (P < .01). Similar results were observed using inverse probability of treatment weighting in the full sample. The odds of being in the MNEP plus TC group was higher for those with work-related exposure to inhalant agents (P = .008), asthma or bronchitis (P = .002), emphysema, fibrosis, and inflammatory status (P = .032), or micronodules on the chest computed tomography scan and respiratory insufficiency (P = .036).

CONCLUSIONS

The association with MNEP seems to represent a clinically and prognostic relevant factor in TC. Hence, careful preoperative workup, systematic pathologic evaluation, including nontumorous lung parenchyma, and long-term postoperative follow-up should be recommended in these patients.

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

Long-Term Imaging Follow-Up in DIPNECH: Multicenter Experience

Diffuse pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pre-invasive disease whose pathophysiology remains unclear. We aimed to assess long-term evolution in imaging of DIPNECH, in order to propose follow-up recommendations. Patients with histologically confirmed DIPNECH from four centers, evaluated between 2001 and 2020, were enrolled if they had at least two available chest computed tomography (CT) exams performed at least 24 months apart. CT exams were analyzed for the presence and the evolution of DIPNECH-related CT findings. Twenty-seven patients, mostly of female gender (n = 25/27; 93%) were included. Longitudinal follow-up over a median 63-month duration (IQR: 31–80 months) demonstrated an increase in the size of lung nodules in 19 patients (19/27, 70%) and the occurrence of metastatic spread in three patients (3/27, 11%). The metastatic spread was limited to mediastinal lymph nodes in one patient, whereas the other two patients had both lymph node and distant metastases. The mean time interval between baseline CT scan and metastatic spread was 70 months (14, 74 and 123 months). Therefore, long-term annual imaging follow-up of DIPNECH might be appropriate to encompass the heterogeneous longitudinal behavior of this disease.

A 68-year-old woman with a diagnosis of asthma and multiple fleeting pulmonary nodules- a case report

Diffuse idiopathic pulmonary neuroendocrine cell (DIPNECH syndrome) remains unfamiliar to most clinicians even though it was first described almost 30 years ago. Diagnosis is usually confirmed histopathologically after lung biopsy, but often, a diagnosis or suspected diagnosis can be made radiographically.

In this paper, we present a case report of a 68-year-old female with shortness of breath and fleeting pulmonary nodules observed on chest CT scan. She was initially misdiagnosed with asthma based on an abnormal pulmonary function test which revealed an obstructive ventilatory defect. The classic radiographic findings of DIPNECH syndrome and the typical patient demographics that should arouse suspicion of a DIPNECH diagnosis were also illustrated.

DIPNECH syndrome is a clinicopathological syndrome whereas focal NECH is a pathological diagnosis that is often made incidentally on histological examination and is encountered in a variety of settings, including in resected carcinoid tumors, in the context of reactive changes concomitant with infection, in metastatic cancer, radiation pneumonitis, intra-lobar sequestration, smokers, interstitial lung disease, and lung adenocarcinoma.

There are no proven treatments for DIPNECH syndrome. In patients with obstructive ventilatory symptoms, bronchodilators with inhaled steroids are usually prescribed. Some severe cases may require parenteral steroids. Somatostatin analogs (SSA) have also been used in some cases with mixed results. Rapamycin has been used in several cases based on the purported activation of the mammalian target of rapamycin (mTOR) in DIPNECH. Some patients with large carcinoid tumors may benefit from resection.

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DIPNECH syndrome is a clinicopathological diagnosis and should not be confused with incidental findings of reactive NECH after surgical lung biopsy.

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DIPNECH syndrome should be suspected in any non-smoking females that present with symptoms of obstructive lung disease and mosaic attenuation on the expiratory film of HRCT of the chest.

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DIPNECH syndrome has a favorable natural course with good prognosis in most patients.

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Most patients with symptoms of dyspnea and cough will respond to bronchodilators and ICS. Occasionally, parenteral steroids might be needed in those with severe symptoms.

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Octreotide scans can be used to identify patients that might benefit from SSA. Sirolimus has also been tried in a few cases with an excellent response.

Coexistence of DIPNECH and carotid body paraganglioma: is it just a coincidence?

SUMMARY

We describe the case of a 56 year-old woman with the almost simultaneous appearance of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) and a carotid body paraganglioma. Of interest, 6 years earlier, the patient underwent total thyroidectomy due to papillary thyroid carcinoma and, in the meantime, she was submitted to mastectomy to treat an invasive ductal carcinoma of the breast. In order to explain these lesions, an extensive genetic study was performed. Results showed positivity for the presence of the tumor suppressor gene PALB2, whose presence had already been detected in a niece with breast cancer. The patient underwent different procedures to treat the lesions and currently she is symptom-free over 2 years of follow-up.

LEARNING POINTS

The presence of two rare neoplasms in a single person should raise the suspicion of a common etiology. To the best of our knowledge, this is the first case that shows the coexistence of DIPNECH and paraganglioma. The contribution of the PALB2 gene in the etiology of these rare neoplasms is a possibility.

NETest Liquid Biopsy Is Diagnostic of Lung Neuroendocrine Tumors and Identifies Progressive Disease

BACKGROUND

There are no effective biomarkers for the management of bronchopulmonary carcinoids (BPC). We examined the utility of a neuroendocrine multigene transcript "liquid biopsy" (NETest) in BPC for diagnosis and monitoring of the disease status.

AIM

To independently validate the utility of the NETest in diagnosis and management of BPC in a multicenter, multinational, blinded study.

MATERIAL AND METHODS

The study cohorts assessed were BPC (n = 99), healthy controls (n = 102), other lung neoplasia (n = 101) including adenocarcinomas (ACC) (n = 41), squamous cell carcinomas (SCC) (n = 37), small-cell lung cancer (SCLC) (n = 16), large-cell neuroendocrine carcinoma (LCNEC) (n = 7), and idiopathic pulmonary fibrosis (IPF) (n = 50). BPC were histologically classified as typical (TC) (n = 62) and atypical carcinoids (AC) (n = 37). BPC disease status determination was based on imaging and RECIST 1.1. NETest diagnostic metrics and disease status accuracy were evaluated. The upper limit of normal (NETest) was 20. Twenty matched tissue-blood pairs were also evaluated. Data are means ± SD.

RESULTS

NETest levels were significantly increased in BPC (45 ± 25) versus controls (9 ± 8; p < 0.0001). The area under the ROC curve was 0.96 ± 0.01. Accuracy, sensitivity, and specificity were: 92, 84, and 100%. NETest was also elevated in SCLC (42 ± 32) and LCNEC (28 ± 7). NETest accurately distinguished progressive (61 ± 26) from stable disease (35.5 ± 18; p < 0.0001). In BPC, NETest levels were elevated in metastatic disease irrespective of histology (AC: p < 0.02; TC: p = 0.0006). In nonendocrine lung cancers, ACC (18 ± 21) and SCC (12 ± 11) and benign disease (IPF) (18 ± 25) levels were significantly lower compared to BPC level (p < 0.001). Significant correlations were evident between paired tumor and blood samples for BPC (R: 0.83, p < 0.0001) and SCLC (R: 0.68) but not for SCC and ACC (R: 0.25-0.31).

CONCLUSIONS

Elevated -NETest levels are indicative of lung neuroendocrine neoplasia. NETest levels correlate with tumor tissue and imaging and accurately define clinical progression.