Artikel
Palpebral myopathology of congenital ptosis
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Autoren
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Harvey B. Sarnat
- University of Calgary-Alberta Children's Hospital, Pathology (Neuropathology), Calgary, Canada
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Laura Flores-Sarnat
- University of Calgary, Paediatrics, Calgary, Canada
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Femida Kherani
- Alberta Children's Hospital, Ophthalmology, Calgary, Canada
| Veröffentlicht: | 11. September 2012 |
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Gliederung
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Background and Objectives: The pathogenesis and aetiology of isolated congenital ptosis of one or both superior palpebrae are unknown. Both the smooth Müller and striated levator palpebrae muscles act synergistically to retract the upper eyelid. No clinical, imaging or pathological evidence is found of dysfunction or malformations of the midbrain or other CNS sites. The objective was to study the myopathology of upper palpebral resections for the treatment of congenital ptosis.
Materials and Methods: Neuropathological examination was performed of 27 upper palpebral resections over 5 years, of 22 patients with isolated congenital ptosis, ages 3 months to 18 years. None had congenital myasthenia gravis, generalised congenital myopathies or mitochondrial cytopathies. Haemangioma invaded the palpebra in 1 patient and epidermal inclusion cyst was found in another. One child had fetal alcohol syndrome. Another had a complex chromosomopathy; another had a genetic syndrome. All patients had normal extra-ocular muscular function and no signs of CNS lesions or generalised neuromuscular disease. Examination was performed of formalin-fixed paraffin sections oriented parallel to the eyelid: H&E and Masson trichrome stains; immunoreactivity for smooth muscle myosin, striated fast and slow myosins, smooth muscle actin, vimentin, alpha-B-crystallin; CD-68; CD-45. Criteria for validity of tissue adequacy were conjunctival (not collagenous) borders and equal distance of conjunctiva to Müller muscle and Müller to distal border. Controls were 3 normal eyelids at autopsy.
Results: Levator palpebrae was hypoplastic or absent and Müller muscle well formed in 16 of 20 patients without intrinsic anatomical lesions of the palpebra. Müller muscle was absent with preserved levator palpebrae in 3 cases. Only one case had no pathological lesions. Non-specific subconjunctival chronic inflammation was seen in almost all.
Conclusions: Most cases of idiopathic isolated congenital ptosis are explained by selective agenesis of the levator palpebrae; a minority has selective agenesis of Müller muscle. Many examples of selective agenesis of single muscles throughout the body are known.
