RESIDENT CASE STUDIES

Week 8 June 9 - June 13, 2003: Case 1   

Table of Contents | List of Diagnoses | Case 1 | Case 2 | Case 3

21 year old female with systemic lupus erythematosus (SLE) WHO classification type V with severe right ventricular dysfunction

Discussion 
Pulmonary arterial hypertension is associated with a variety of clinical conditions that broadly include cardiac disease (shunts), intrinsic lung disease (emphysema, fibrosis), and pulmonary arterial disease (thromboemboli). Cryptogenic pulmonary hypertension refers to patients that typically fall into the following categories: primary plexogenic hypertension, thrombotic pulmonary hypertension, and pulmonary veno-occlusive disease, all of which are rare. Collagen vascular disease, in this case systemic lupus erythematosus (SLE), may also be associated with pulmonary hypertension. Deposition of immune complexes within vessels is believed to cause pulmonary hypertension in these patients. Plexogenic arteriopathy is an uncommon but well-documented finding in this setting.^1,2 

Histologically, the earliest vascular finding in pulmonary hypertension is muscularization of pulmonary arterioles and medial hypertrophy of muscular pulmonary arteries. Strictly speaking, medial hypertrophy is defined as medial thickness greater than 7% of the external vascular diameter. With progressive disease, there is intimal hyperplasia with progressive narrowing of the vascular lumen. Vessels are further narrowed by concentric laminar (onion-ring) subintimal fibrosis and reduplication of the internal elastic membrane. The proliferating cells are believed to be myofibroblasts. In advanced disease, one sees plexiform lesions, produced by aneurysmal dilatation of pulmonary arterioles and the formation of eccentric, glomeruloid nodules containing capillary or sieve-like channels. Fibrin thrombi may be seen in these lesions. Complex plexiform lesions can mimic recanalized thrombi and may erroneously lead to a diagnosis of thromboembolic disease. Fibrinoid necrosis and arteritis may be found in patients with severe pulmonary hypertension and portend a poor prognosis.^1,2  

References:

¹Travis WD, Colby TV, et al. Atlas of Nontumor Pathology: Non-Neoplastic Disorders of the Lower Respiratory Tract. American Resistry of Pathology and the AFIP:Washington, D.C. 2002. 

²Sternberg SS, ed. Diagnostic Surgical Pathology, vol 1 , 3^rd ed. Lippincott Williams and Wilkins: New York, 1999.