PART TWO
Diagnostic Cytology
Often nuclear grooves parallel to the long axis of the nucleus
may be evident. Immunochemical verification is often quite
helpful for aiding diagnosis but cannot reliably distinguish
between some primary and metastatic lesions.89
Retinoblastoma,
the most common intraocular tumor of
children,66,90,91 may be genetically transmitted as an autosomal
dominant. Family history is therefore significant. Its bilaterality
in approximately a third of cases makes it all the more tragic.
Early diagnosis and treatment are critical to save the patient.
The lesion may appear as a retinal, subretinal, or vitreal mass
(Fig. 17.21).
Table 17.3 Hstologic Diagnoses of Aspirated Intraocular Tumors from
the Literature
Diagnosis
Number of cases
Melanoma
85 (75%)
Metastases
7
Retinoblastoma
4
Astrocytoma
3
Medulloepithelioma
2
Mesectodermal leiomyoma
2
Hurthle cell carcinoma
1
Carcinoid tumor, metastatic
1
Nevus
1
Inflammation
1
Lymphoma
1
Rhabdomyosarcoma, iris
1
Pigmented adenoma, ciliary body
1
Melanocytoma
1
Retinal pigment epithelial hyperplasia
1
Retinal pigment epithelial adenocarcinoma
1
Total
113
Reproduced from Glasgow BJ, Straatsma BR, Kreiger AE. Fine-needle aspiration of
posterior segment intraocular tumors.
O phthalm ol Clin North Am
1995;8:67-72.
The small tumor cells with invisible cytoplasm have cytologic
features characteristic of all the neural ectodermal (neural crest)
tumors and therefore cannot be distinguished morphologi-
cally. Clinical presentation and history are essential to confirm
the diagnosis. Because these tumors frequently extend into the
central nervous system (CNS), a spinal tap for cytologic exami-
nation of cerebrospinal fluid is critical to preoperative staging
and postoperative treatment.66 In both FNA and cerebrospinal
fluid examinations, scant cytoplasm, dark polygonal nuclei of
almost identical size, smudged nuclear chromatin, inconspicu-
ous nucleoli, and nuclear molding, requiring cell clusters in
the sample, are mandatory criteria. In FNA preparations, the
presence of rosettes, and particularly fleurettes, may be diag-
nostic. Flexner-Wintersteiner rosettes are formed by peripheral
arrangement of nuclei with finely fibrillar cytoplasmic proc-
esses radiating to the center of the circle. Fleurettes demonstrate
photoreceptor cell differentiation and are found only in well-
differentiated retinoblastomas. In general, FNA and vitrectomy
are considered by many to be contraindicated in retinoblastoma
because of the risk of orbital seeding.
Lymphomas
rarely involve the eye, but when they do, approxi-
mately 60-80% of patients with primary intraocular lymphoma
have CNS involvement, resulting in death.92 According to a
recent report, the mean time between the onset of ocular symp-
toms and the onset of CNS symptoms is 29 months (range,
7 to 108).93 However, the diagnosis of intraocular lymphoma
is difficult and often delayed, because the disease is misdiag-
nosed as idiopathic uveitis. A negative biopsy does not exclude
lymphoma, as only reactive lymphocytes may be found in vit-
reous biopsies, and neurological investigations, cerebrospinal
fluid studies, and multiple vitreous biopsies may be required to
obtain a positive diagnosis.69
In a retrospective review of 14 patients with intraocular
lymphoma, designed to establish the relative value of cytologic
features and immunologic markers, it was concluded that mor-
phology (e.g. irregular nuclear outlines, prominent nucleoli, and
coarsened chromatin) is still the most sensitive parameter for
accurate diagnosis.94 More recently, in a study of 78 consecutive
patients (84 eyes) which underwent pars plana vitrectomy for
diagnostic purposes, the PPV (positive predictive value) for lym-
phoma with a positive cytologic evaluation was 100%, and the
NPV was 61%.95 A direct, head-to-head comparison of cytology
and flow cytometry has also been performed, which compared
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Fig. 17.20 Uveal melanoma. (A) Spindle type. (B) Epithelioid type. Fine-needle aspiration (Papanicolaou x HP).
466
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