some institutions, vitrectomy samples are processed routinely. The
ophthalmic pathologist can provide the following types of feedback
from the routine study of vitrectomy specimens:
of unsuspected retinal tissue.
of internal limiting membrane from procedures involving stripping
of epiretinal membranes
of iron (toxic to the retina) in cases of long-standing vitreous
of hypertrophic retinal pigment epithleial cells in cases of retinal
detachment repair, perhaps suggesting early proliferative vitreoretinopathy
substances in the vitreous such as amyloid
the pseudophypha in this vitrectomy sample from a patient with suspected
surgeons may also request that samples be sent to the pathology laboratory.
The most common indication for the specific examination of vitreous
material is to rule out retinal lymphoma.
ophthalmologist should keep the following points in mind when planning
for an intraocular biopsy to rule out retinal lymphoma:
patients with systemic lymphoma, the uvea is usually infiltrated.
In patients with CNS lymphoma, the retina and sub-RPE compartments
are usually infiltrated and the uvea may be thickened by an infiltrate
of benign lymphocytes. By aspirating vitreous, the surgeon
is attempting to collect cells that have spilled over from the neurosensory
it is best if the surgeon tries to aspirate directly over a lesion
rather than sample from the center of the vitreous.
is best to obtain a direct aspirate before beginning to use the
vitrectomy instrument. There are several reasons for this:
vitrectomy instrument cuts, aspirates, and infuses balanced
saline. The mechanical action of cutting and aspiration may
lyse neoplastic lymphocytes, and exposure to balanced saline
may also damange neoplastic lymphocytes.
alert the pathology laboratory before beginning the procedure. It
is best if a technician is present in the operating room to receive
the direct aspirate sample. The vitrectomy collection container
should also be submitted, but the quality of cytology may not be
as good as the material aspirated directly.
pathology laboratory can assess the morphology of the vitreous infiltrate,
and immunocytochemistry can be performed on prepared slides. If
sufficient quantities of cells are available, it is possible to
perform flow cytometry on these samples.
quantities of vitreous fluid containing visible particles may be processed
by cell block.
submitted for possible retinal lymphoma may be processed by cytospin
to allow for better cellular preservation.
PAS stain may be helpful in identifying basement membrane structures,
such as the internal limiting membrane.
retinal lymphoma is usually a large cell lymphoma, B-cell type.
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