Background:Neurofibromatosis type 1 (NF1)-associated interstitial lung disease (NF-ILD) represents an uncommon pulmonary manifestation frequently misdiagnosed as asthma, largely due to insufficient clinical recognition. This report describes a case of NF-ILD that remained misdiagnosed over an extended period, with the aim of improving diagnostic awareness among clinicians. Case presentation: A 51-year-old male with a long-standing history of neurofibromatosis type 1 (NF1) underwent evaluation in February 2023 for chronic cough. Initial high-resolution computed tomography (HRCT) of the chest revealed bilateral thin-walled cysts, predominantly distributed in the upper lobes with scattered involvement of the lower lobes. The cysts exhibited thin walls without associated nodules. Pulmonary function tests (PFTs) demonstrated mild obstructive ventilatory impairment and a positive bronchial provocation test, consistent with the diagnosis of cough-variant asthma. Partial symptomatic improvement was achieved with inhaled corticosteroids combined with a long-acting β₂-agonist (ICS/LABA); however, symptoms subsequently recurred. In December 2025, the patient underwent re-evaluation due to a persistent cough. Given the atypical radiographic presentation of cystic lesions on high-resolution computed tomography (HRCT) in the context of asthma, interstitial lung disease was suspected. Subsequent pulmonary function testing revealed a mild reduction in the diffusing capacity for carbon monoxide (DLCO), (measured at 55% of the predicted value. An extensive diagnostic workup was conducted, which excluded allergic bronchopulmonary aspergillosis (ABPA), eosinophilic granulomatosis with polyangiitis (EGPA), smoking-related pulmonary pathology, and connective tissue disorder-associated interstitial lung diseases. Based on the presence of characteristic extrapulmonary features of neurofibromatosis type 1 (NF1)—including multiple cutaneous neurofibromas and café-au-lait macules—coupled with the comprehensive exclusion of other cystic lung diseases, a clinical diagnosis of NF1-associated interstitial lung disease (NF-ILD) was established. Conclusions: Non-specific interstitial lung disease (NS-ILD) is frequently misdiagnosed as asthma over extended periods due to symptomatological overlap and a partial response to therapeutic interventions such as inhaled corticosteroids and long-acting beta-agonists (ICS/LABA). In patients with neurofibromatosis type 1 (NF1) who present with respiratory symptoms and demonstrate a suboptimal therapeutic response to conventional asthma management, prompt evaluation via high-resolution computed tomography (HRCT) and assessment of diffusion capacity for carbon monoxide (DLCO) is recommended. A comprehensive differential diagnostic workup is imperative in cases exhibiting atypical presentations of asthma, and abnormal HRCT findings should prompt further investigation to elucidate potential underlying etiologies and preclude diagnostic oversight.