Neuroendocrine Hyperplasia of Infancy: Imaging Features and Differential Diagnoses
Aditi A. Desai, MD; Yu Luo, MD PhD
Neuroendocrine hyperplasia of infancy (NEHI) is form of pediatric interstitial lung disease that was first described in the literature in 2005. Since its original report, much more work has been carried out to better comprehend this previously poorly understood entity. The radiologist’s familiarity with the clinical presentation and associated imaging findings is key to making an accurate diagnosis and ensuring appropriate management of these patients, as their presentation can often be nonspecific.
The purpose of this exhibit is to review the clinical findings and radiologic features of NEHI. The differential diagnoses will also be explored, with emphasis on the clinical and imaging features that help differentiate these alternate diagnoses from NEHI.
Clinical Presentation of NEHI
Before NEHI was described as a unique entity, patients were described as having “persistent tachypnea of infancy”. They presented with symptoms consistent with interstitial lung disease (persistent tachypnea, hypoxia, retractions, respiratory crackles, failure to thrive), and with non-diagnostic lung biopsies, though an increased number of bombesin-positive neuroendocrine cells is now diagnostic of NEHI.
Laboratory and clinical work-up is negative, and chest radiography can be normal or demonstrate hyperexpansion, an non-specific finding. Pulmonary function testing shows obstruction with profound air-trapping.
Patients typically require supplemental oxygen and are symptomatic despite treatment (inhalers/steroids/AZA). However, by 5 years of age, most all are off suppelmental oxygen with normalization of PFTs and resolution of imaging findings.
High Resolution CT Findings of NEHI
Ground Glass Opacities (GGOs): This is the most severe finding, seen in 96% of cases. GGOs are present in central and peripheral distribution, involving ≥4 lobes, with the right middle lobe and lingula most predominantly involved.
Air Trapping: This is present in up to 93% of patients, but only detected if expiratory phase imaging is obtained.
Additional Abnormalities: GGOs and air trapping are the only findings in up to 65% of NEHI patients. Additional findings (consolidations, bronchial wall thickening, bronchiectasis, linear/reticular opacities, nodules, honeycombing) may be present, but are less prominent than GGOs and air trapping.
Temoral Resolution: Imaging features typically resolve by 5 years of age.
Bronchiolitis Obliterans: Bronchiectasis is the most predominant feature, not GGOs.
Surfactant Protein Abnormalities: GGOs are present, but much more diffuse with septal thickening, and a worse clinical course.
Asthma: Air trapping is predominant finding. If GGOs are present, they are less predominant than air trapping and do not have predilection for RML/llingula.
Hypersensitivy Pneumonitis: GGOs are present, but in conjunction with diffuse, ill-defined cetrilobular nodules (arrows) and mosaic perfusion. Findings and symptoms resolve with removal of offending agent.
Deterding RR, Pye C Fan LL, et al. Persistent tachypnea of infancy is associate with neuroendocrine cell hyperplasia. Pediatr Pulmonol 2005; 40:157-65.
Lukkarinen H, Pelkonen A, Lohi J, et al. Neuroendocrine hyperplasia of infancy: a prospective follow-up of nine children. Arch Dis Child 2013 Feb; 98(2):141-4.
Brody AS, Guillerman RP, Hay TC, Wagner BD, Young LR, et al. Neuroendocrine hyperplasia of infancy: diagnosis with high-resolution CT. AJR Am J Roentgenol 2010 Jan; 194 (1):238-44.