Table 2: Current Histopathologic Classification Scheme for Plexogenic Arteriopathy (PA) in Pulmonary Hypertension (PH) [adapted from Katzenstein et al.] 3 Grade Predominat Pathogenic Process Histologic Features Grade I (early) Thickening of vascular medial (increased muscularity) Thickening and proliferation (hypertrophy and hyperplasia) of smooth muscle in the arterial media to >5%-7% of the diameter of the vessel Grade II-III Thickening of vascular intima Proliferation (hyperplasia) of arterial intima causing an
failure is needed. Further signs of right heart failure in the current case include the right-sided cardiac dilatation, car- diomegaly, and hepatomegaly. As previously mentioned, autopsy studies depicting the morphologic changes seen in SCD lungs have provided valuable insights into SCD as a cause of PH. Further studies are warranted, as our un- derstanding of the processes underlying PA continues to evolve and our efforts turn to therapies targeted at each of the clinical subgroups or perhaps each of the histopathologic grades of lesions. 13,14 ACKNOWLEDGEMENTS The authors would like to gratefully acknowledge the support of the Orleans Parish Coroner’s Office for providing the case material for this report. REFERENCES 1. Simonneau G, Gatzoulis MA, Adatia I, et al. Updated clinical classification of pulmonary hypertension. J Am Coll Cardiol . 2013;62:D34-41. 2. Wagenvoort CA. Plexogenic arteriopathy. Thorax . 1994;49:S39-S45. 3. Katzenstein ALA, Askin FB, Livolsi VA, et al. “Pulmonary Hypertension and Other Vascular Disorders.” Katzenstein and Askin’s Surgical Pathology of Non-neoplastic Lung Disease . Philadelphia: W.B. Saunders, 1997. 434-57. Print. 4. Fishman AP. Changing concepts of the pulmonary plexiform lesion. Physiol Res . 2000;49:485-492. 5. Rees DC, Williams TN, Gladwin MT. Sickle-cell disease. Lancet. 2010;376:2018–2031. 6. Siddiqui AK, Ahmed S. Pulmonary manifestations of sickle cell disease. Postgrad Med J . 2003;79:384-390. attenuated lumen (Grade II) followed by deposition of collagen and/or elastin fibers (fibrosis) around the arterial lumen in a concentric (onion-ring) fashion (Grade III) Localized dilatation of the arterial branches arising from a thick-walled parent artery due to marked degeneration of the vascular media. When arterial branch dilatation affects a cluster of vessels, it is termed an angiomatoid lesion Plexus of capillary-like channels within a dilated arterial branch of the thick-walled parent artery that yields a glomoid appearance to the vessel + overlying thrombotic material Fibrinoid necrosis of smooth muscle in the vascular media + a necrotizing arteritis with either lymphocytes or neutrophils
Group IV
Dilatation and degeneration
Grade V (hallmark lesion)
Plexiform proliferation
Vascular necrosis + inflammation
Grade VI (rare)
mean pulmonary arterial pressure (PAP) >25 mmHg. Using PAP pressures, the estimated prevalence of PH in SCD has been reported to be approximately 10%. 10 Autopsy studies in patients with SCD, however, have yielded rather differ- ent information. In one study, changes of PH were found in 100% (20 of 20) of the autopsied individuals with SCD; 11 while in another, more recent study conducted by Graham et al., 12 PH changes were found in only one-third of its 21 SCD decedents who underwent autopsy. The histopatho- logic severity of vascular lesions associated with PH in SCD has also been debated in the autopsy literature, with the hallmark Grade V plexiform lesion being recognized by one series in 12 of 20 patients (60%) 11 but in only 1 of 21 patients (0.05%) in the more recent study. 12 Aside from SCD as a cause of PH, extensive research and ample literature over the last 50 years have greatly expanded the number of clinical disorders known to cause PH, including pulmonary capillary hemangiomatosis, veno-occlusive disease, interstitial lung disease, sarcoidosis, chronic obstructive lung disease, left heart dysfunction, and individuals harboring a bone morphogenic protein receptor type 2 (BMPR2) mutation. The vast majority and diversity of these causes was considered in the development of the newest consensus clinical subcategories of PH. 1 The autopsy case depicted here of a young adult with SCD demonstrates the hallmark plexiform lesion (Grade IV) seen in plexogenic arteriopathy (PA) of PH. Greater aware- ness is needed of the fact that lung manifestations of SCD remain the main contributors to morbidity and mortality. With the nonspecific clinical presentation of PH in SCD, a higher index of clinical suspicion for PA and right heart
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