Neurofibromatosis type 1 can cause conductive hearing loss when it invades the ear canal as a plexiform lesion in the preauricular area.
The disease can manifest as one of several types of lesions, including cafe au lair spots, cutaneous tumors, plexiform lesions, axillary freckling, Lisch nodules of the iris, optic gliomas, and bony abnormalities.
The vascular changes, which included medial and intimal thickening, angioblastic proliferation, plexiform lesions
, and dilation lesions, occur in a setting of hypoxia, chronic inflammation, and high pressure and flow via a systemic arterial supply (7).
Solitary lesions may be very well defined; plexiform lesions
are ill defined and infiltrative.
The pulmonary hypertension causes medial hypertrophy of the pulmonary arteries, often intimal fibrous thickening, and occasionally plexiform lesions
in the lungs.
In this clinical setting, the plexiform-like lesions could not be clearly discriminated from recanalized thrombi, (14) therefore they were not regarded as being identical to the plexiform lesions
of primary PH.
Eleven percent had medial hypertrophy and intimal fibrosis without plexiform lesions, 7% had pulmonary veno-occlusive disease, and 4% had in situ thrombosis as the prominent histologic finding.
23-28] Cool et al [27,28] identified endothelial cells as the predominant component of plexiform lesions and concentric obliterative vascular lesions.
Cool CD, Kennedy D, Voelkel NF, et al: Pathogenesis and evolution of plexiform lesions in pulmonary hypertension associated with scleroderma and human immunodeficiency virus infection.
In summary, the patient had morphologic evidence of chronic pulmonary hypertension that probably was reversible as evidenced by the absence of plexiform lesions
4] In another series of radiographic and histopathologic examination of 20 patients with pulmonary hypertension, cholesterol granulomas were found in 5 cases, but no association with plexiform lesions was suggested.
Plexiform lesions were seen in arterioles throughout the lungs.