LETTERS TO THE EDITOR 49 Table 1 Clinical characteristics of all reports of malignant hypertension with diffuse alveolar haemorrhage. Case Age Gender Nationality Smoking Previous HT Family history of HT Air travel Ref. 1 34 Male Japanese NR 1 month NR NR 1 2 26 Male North American 1---2 cig./day No Both parents Yes 5 3 26 Male Japanese NR 3 years NR Yes 3 4 38 Male Canadian 9 packs-year 3 months NR NR 4 5 32 Male Japanese NR 5 years Both parents NR 6 6 27 Male Japanese >30 pack-year No NR NR 2 7 51 Male Portuguese >30 pack-year No Mother No --- HT: systemic hypertension; cig.: cigarette; NR: no reference; Ref.: reference. However, it is worth noting that no other findings have sup- ported this hypothesis, and this may be just a non-significant association. In conclusion, our and previous reports of malig- nant hypertension associated DAH suggest that high blood pressure may be a significant cause of alveolar haemorr- hage. Clinicians caring for DAH patients should be aware of this association. We also propose large-scale studies on the association between systemic blood pressure and the risk of alveolar haemorrhage which could open the way to new treatment of DAH with BP lowering agent. Disclosure The authors report no financial support, off-label or inves- tigational drug use. Conflicts of interest The authors have no conflicts of interest to declare. References 1. Hida K, Wada J, Odawara M, Kunitomi M, Hayakawa N, Kashihara N, et al. Malignant hypertension with a rare complication of pul- monary alveolar hemorrhage. Am J Nephrol. 2000;20:64---7. 2. Park HS, Hong YA, Chung BH, Kim HW, Park CW, Yang CW, et al. Malignant hypertension with an unusual presentation mimicking the immune mediated pulmonary renal syndrome. Yonsei Med J. 2012;53:1224---7. 3. Sato Y, Hara S, Yamada K, Fujimoto S. A rare case of alveolar haemorrhage due to malignant hypertension. Nephrol Dial Trans- plant. 2005;20:2289---90. 4. Aithal S, Marley N, Venkat-Raman G. An unusual non- immunological cause of renal pulmonary syndrome. Clin Nephrol J. 2009;72:322---5. 5. Dalal P, Phadke G, Gill A, Tarwater K, Misra M, Pele N, et al. Case report --- A patient with hemoptysis and renal failure. Int J Hypertens. 2011;2011:1---3. 6. Nanba K, Yahata K, Kikuchi Y, Okamoto C, Seta K, Sug- awara A. A rare case of malignant-phase hypertension with pulmonary alveolar hemorrhage. Clin Exp Nephrol. 2011;15: 303---7. Joana Clemente Duarte a,∗ , Rita Leal b , Luís Escada b , Tiago M. Alfaro a a Pneumology Unit A, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal b Nephrology Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal ∗ Corresponding author. E-mail address: Joana Duarte 17@hotmail.com (J.C. Duarte). http://dx.doi.org/10.1016/j.rppnen.2016.10.002 2173-5115/ © 2016 Sociedade Portuguesa de Pneumologia. Published by Elsevier Espa˜ na, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Mesothelial cyst of the pulmonary ligament: An uncommon lesion Dear Editor, The importance of a thorough knowledge of thoracic anatomy is timeless. Lung and pleural anatomy continues to be a subject for study nowadays, not only due to the greater spatial resolution of newer diagnostic studies, such as bron- choscopy, computed tomography and magnetic resonance, but also because of advances in thoracic surgery. The pulmonary ligaments are among the lesser known structures of the thoracic anatomy. The radiological impor- tance of the pulmonary ligament was first described in 1966 by Rabinowitz and Wolfe, 1 and only very few reports or series have been found which describe the radiologi- cal findings of pathologic processes within the pulmonary ligaments. 1---6 This ligament, just like any other thoracic anatomical structure can be affected by non-infectious or infectious inflammatory processes, tumors, congenital or developmental abnormalities and scarring. 2---6 There are only a few reports in the literature which mention this anatomical structure and different pathological process. The following case description of a cystic lesion within the right pulmonary ligament illustrates the anatomy and pathology of this structure: A 75-year-old woman diagnosed with a pharyngeal can- cer was referred for magnetic resonance imaging of the neck and a computed tomography (CT) of the chest and