Purpose: Amyloidosis refers to a heterogeneous group of disorders associated with deposition of chemically distinct fibril proteins. Isolated orbital amyloidosis is a rare condition and requires systemic examination. The authors report a case of amyloid deposit in the orbit whose systemic investigation has been negative.
Methods: A 64-year-old woman presented to the eye clinic with left-sided orbital mass, mild exophthalmos with downward ocular displacement, and ptosis. The patient presented also visual acuity loss and ocular hypertension. No systemic involvement was noted by systemic workup and it confirmed the primary orbital amyloidosis.
Results: The patient was subject to full clinical examination, laboratory examinations, orbital echography, magnetic resonance imaging and total body computed tomography scans, rectal mucosa, and temporal artery biopsies. It was necessary to exclude systemic amyloidosis. The presence of amyloid deposits was confirmed by biopsy of orbital mass. The chemical nature of deposit was characterized using light microscopy, immunohistochemistry, and electron microscopy.
Conclusions: Orbital amyloidosis is a very rare disease. It should be considered in the diagnosis of patients with ptosis and exophthalmos. The treatment usually consists of surgical removal of the amyloid mass and follow-up for a likely local recurrence. In our case, mass excision determined the decrease of exophthalmos and intraocular pressure.