Histology Course S IV 16 Department of Pathology, University of Zurich Histokurs

S IV 16 plexiform pulmonary arteriopathy (primary pulmonary hypertension) Orcein-Sirius  
  ICD-10: I27.0

35-year-old female with increasing dyspnoea. Right heart failure, autopsy specimen.

- Largely unremarkable lung parenchyma with main findings on arteries. Changes in the vessels changes have been caused by pulmonary hypertension.
Muscular arteries (diameter 0.1-1 mm):
- Hyperplasia of media (corresponds to grade I of hypertensive lung vessel changes)
- Onion-bulb-like thickening of intima with varying proportion of cells and fibres. Narrowing of lumen to the point of obliteration (depending on number and extent of change grade II or II)
- Net-like division of lumen by cell-rich septa (plexiform lesions): often in smaller, thin-walled and dilated side branches of largely obliterated muscular arteries. Angioma-like increase of dilated cavernous vessels (angiomatoid lesions, grade IV)
Arterioles (diameter <80 um): muscularisation, i.e continuous elastic lamella and smooth muscle in the vessel wall.
Elastic arteries (diameter >1 mm): pulmonary sclerosis, i.e arteriosclerotic changes comparable with lesions in the large cardiovascular system.

The diagnosis " plexogenous pulmonary arteriopathy" can be made with the presence of plexiform lesions (Caution: can be mistaken for organized emboli)
All given specimen show numerous hypertensive lesions up to grade III. Plexiform lesions are not evident on all specimen as they are rare.

Occurrence: in cardiac shunting, rarely in liver cirrhosis, in some HIV-infected patients, idiopathic, in the 70s following intake of the appetite suppressant Aminorex