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

Constrictive bronchiolitis in diffuse idiopathic pulmonary neuroendocrine cell hyperplasia

“…Similar to others, our cohort was predominantly comprised of middle-aged and older women, with a female:male ratio of 10:1. [10,11,13,19] The most common presenting symptoms were chronic cough and dyspnea, with a median symptomatic duration of 10 years prior to DIPNECH diagnosis. 45% of our cohort, 50% and 63% of two other cohorts had been given a diagnosis of another obstructive lung disease prior to DIPNECH diagnosis.…”

“…45% of our cohort, 50% and 63% of two other cohorts had been given a diagnosis of another obstructive lung disease prior to DIPNECH diagnosis. [10,19] Given its rarity, DIPNECH is under-recognized as a potential cause for obstructive lung disease, particularly in women, and the diagnosis is often delayed.…”

“…Bronchospasm may simply be due to a comorbid reactive airway disease like asthma, or, theoretically, may be related to increased amounts of bioactive substances (e.g., histamine and 5hydroxytryptamine) secreted by the hyperplastic PNECs and carcinoid cells, and exerting their effect locally, on adjacent airways, rather than systemically; [23,24] 33 patients in this study and two others had 5-HIAA measured; only one patient had 5-HIAA elevation. [10,19] Although incompletely understood, tissue fibrosis (e.g., in mesenteric tissue and cardiac valves) is a well-known complication of neuroendocrine tumors (NETs). Serotonin and several growth factors have been implicated in its pathogenesis.…”

“…However, it is unclear whether the uptake was exclusively in the dominant lesion as reported by Gorstein et al, or more diffuse. [19,28] The small size of the lesions found in DIPNECH negatively impacts the sensitivity of SSTR imaging modalities; hence, a negative study does not rule out the possibility of SSTR expression by those lesions. [33,34] Therefore, using SSAs in the treatment of DIPNECH, irrespective of the findings on SSTR imaging, is plausible.…”

“…SSA use has been reported in patients with DIPNECH. [10,19,28,35] pathway, which led to the successful use of everolimus, an mTOR inhibitor, in improving outcomes in patients with NETs of different origins. [37] This activation of mTOR pathway was also demonstrated in DIPNECH.…”