From Cancer Mimicking Orphan Lung Disease to Orphan Thoracic Oncology
Résumé
A variety of rare neoplastic and non-neoplastic disorders may develop in the lung, the pleura, and the mediastinum. Some may have a propensity to mimic lung carcinoma as well as benign orphan lung diseases at some level of examination, as they may share with these clinical, imaging, pathological, and even molecular features. Challenges in the differential diagnoses among reciprocal mimics are well illustrated through examples as bronchioloalveolar carcinoma, primary pulmonary lymphomas, and vascular sarcomas. Pseudotumors have further been described, actually corresponding to a heterogeneous group of diseases characterised by circumscribed fibrous tissue and inflammatory cells. Among the inflammatory pseudotumors, neoplastic/non-neoplastic borderline disorders have been identified, such as inflammatory myofibroblastic tumor, which presents with clonal proliferation and has eventually emerged as a true neoplasm. Finally, some rare pulmonary diseases are emerging as borderline neoplastic non-neoplastic disorders, that require multidisciplinary expertise both in the field of orphan pulmonary diseases and in thoracic oncology, including amyloidosis or even Langerhans cell histiocytosis. Ultimately, implementing multi-disciplinary expert consensus is mandatory to determine the optimal management of these disorders.