• Hypersensitivity Pneumonia (HP).
• Idiopathic Pulmonary Fibrosis (IPF)
• ILD
• Interstitial lung diseases (ILDs)
• multidisciplinary discussion (MDD)
• Non-specific Interstitial pneumonia (NSIP)
• Usual Interstitial Pneumonia (UIP)

INTRODUCTION
Interstitial lung diseases (ILDs) are a complex group of diffuse lung diseases characterized by different causes, clinical presentation, treatment, and prognosis. Since the publication of ATS/ESR consensus in 2002, the role of multidisciplinary approach to ILDs is well known and further studies highlighted the impact of multidisciplinary discussion (MDD) in ILDs’ evaluation.
The aim of this retrospective study was to describe the role of MDD in the management and diagnosis of ILDs and to assess the accuracy and confidence of the diagnosis on the base of the subsequent follow-up.

MATERIAL AND METHODS
A single centre retrospective observational study was conducted at the Pisa University Hospital. A multidisciplinary group for ILDs diagnosis was instituted in 2012. It was formed by pneumologists, radiologists, a pathologist, occupational clinicians and occasionally rheumatologists and thoracic surgeons. Monthly meetings took place since July 2012 and all patients referred till August 2022 were included in the study.

RESULTS
Altogether 178 meetings were held, and 1240 patients were evaluated. Each patient was discussed at least once, with a maximum of five times. 772 common multidisciplinary diagnoses were achieved, while in 458 cases it was not possible to give a final diagnosis. The most frequent multidisciplinary diagnoses were idiopathic pulmonary fibrosis (IPF), non-specific interstitial pneumonia (NSIP) and smoking related ILDs. In 9% of cases a histological evaluation was performed, and this brought to a diagnosis in 75% of cases, IPF was the most frequent. Then all cases with at least one year of follow-up after the multidisciplinary discussion were revised. Common diagnoses were confirmed or modified; while the diagnostic hypotheses were changed into revised diagnoses or left as hypothesis as they still could not be confirmed. Among common diagnoses, 61% were confirmed while 36% were not confirmed as patients didn’t perform further exams or visits. Eighteen diagnoses were modified (3%). Of the diagnostic hypothesis, 57% changed into revised diagnoses while 43 % couldn’t be changed. The 72% of revised diagnoses agreed with the first diagnostic hypothesis stated at MDD.

CONCLUSION
The role of MDD in ILDs assessment and diagnosis was confirmed. Moreover, MDD must be considered as a dynamic process and may be applied also for long-term evaluation as diagnosis may change on the basis of clinical course.