SYMPOSIUM ON OPHTHALMIC CYTOLOGY
|Year : 2007 | Volume
| Issue : 1 | Page : 11-15
|Introduction to ophthalmic cytology - modalities and classification of neoplasms
Department of Pathology, Medical College, Kota, Rajasthan, India
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Keywords: Ophthalmic cytology, modalities, classification of neoplasms
|How to cite this article:|
Rai N N. Introduction to ophthalmic cytology - modalities and classification of neoplasms. J Cytol 2007;24:11-5
| Introduction|| |
Ophthalmic pathology is unique in many respectas it encompasses wide range of tissues - epithelia, connective tissue and specialized tissue; it offers exposed surfaces and fluid filled chambers for diagnosis; it shows wide range of infections and Neoplasia-some are variants of similar tumours that present elsewhere and other are unique to eye; tumours show a well differentiated morphology to an undifferentiated primitive small cell feature. Many Neoplastic conditions masquerade as or mimic other less aggressive Neoplastic or non-Neoplastic inflammatory conditions and needs differentiation before definitive therapy is planned. A general surgical pathologist and cytopathologist might be un-familiar with the terminology and have limited experience in ocular tumours. Ophthalmic Cytology as a special procedure has been in use since many years. It is useful when clinical examination and non-invasive techniques fail to establish the diagnosis and early diagnosis needed when a potentially aggressive disease warrants a prompt surgical/therapeutic decision. Innovations in sampling techniques using small caliber needles guided by precise Imaging modalities have made Cytology a relatively simple, safe and accurate technique. Aim of this Symposium is to provide Pathologists a comprehensive account of application and utility of cytological techniques in eye.
| Surface Cytology Techniques|| |
External surface of eye includes eyelid skin, lid margin, conjunctiva and cornea. They are readily accessible for simple cytological procedures within reach of any ophthalmologist or cytopathologist. Further sophistication of these techniques has expanded the scope of diagnosis and research.
| Scrape Cytology|| |
Ulcerated skin of eye-lid can be scraped safely and it gives better results than fine needle aspiration cytology (FNAC) in ulcerated basal cell carcinoma. It is recommended to combine FNAC with scrape cytology for any ulcerated lesions of eyelid skin and conjunctiva.  Scraping of conjunctiva and cornea for surface lesions is, to be done under local anesthesia. Scrape is done with spatula or scalpel blade. However for conjunctival and corneal surface lesions, use of modified small endo-cervical brush with short, soft bristles (Cytobrush, S-brush) is recommended.  A new type of brush with a spherical tip (Acellon-M) was described by Fujihara et al  which has improved cell collection from conjunctival epithelium when the target cells are in a limited area. Combined with flow cytometry, the technique provides an additional diagnostic or research tool.
| Impression Cytology|| |
Impression cytology refers to the application of a cellulose acetate filter to the ocular surface to remove the superficial layers of the ocular surface epithelium, generally removing 2-3 layers, but deeper cells can be accessed by repeat application over the same site. After local anesthesia, a cellulose acetate strip is placed on the surface of conjunctiva/cornea using gentle pressure, carefully peeled off, fixed in alcohol and stained with Papanicolaou stain, H and E or Periodic acid schiff's stain. Material can also be subjected to histo-pathology. Modifications in techniques like use of Biopore membranes or by transferring impressions from cellulose acetate filter to a gelatin coated glass slide; have extended its use in transmission electron microscopy, polymerase chain reaction (PCR), flowcytometry and immuno-histochemistry.  Its application include diagnosing a wide range of ocular surface disorders including ocular surface squamous neoplasia (OSSN), documenting sequential changes in the conjunctival and corneal surface over time, staging conjunctival squamous metaplasia, and monitoring effect of treatment. 
| Fine Needle Aspiration Cytology|| |
FNAC is an efficient, economical and relatively safe method of diagnosis when non-invasive techniques fail to confirm or rule out the suspicion of malignancy.  It is advisable that except eye-lid, use of ophthalmic FNAC be restricted to centers where close cooperation is possible between ophthalmologist, cytopathologist and ophthalmic pathologist. 
Indications of Ophthalmic FNAC: FNAC is indicated in ophthalmic lesions in following situations. ,
- Pre-treatment assessment of suspected lid tumours, where poor operative selection by nonophthalmologic surgeons and dermatologists is the rule.
- Pre-operative assessment of ocular or conjunctival melanosis where conservative management is advisable.
- Pre-treatment selection of patients with visible, palpable or imaged orbital masses where open biopsy or excision is often consequently rendered un-necessary and undesirable.
- Pre-operative assessment of uveal melanoma, where enucleation is being considered. Small melanomas prior to irradiation or laser therapy.
- Pre-operative diagnosis of suspected lacrimal gland tumours (to avoid incomplete excision and orbital recurrence).
- Pre-treatment selection of patients with visible, palpable or imaged orbital masses.
- Suspected metastatic lesion.
- Any intra-orbital mass in which possible hemorrhagic complication would not seriously preclude clinical selection of local excision, laser ablation or irradiation and follow-up.
Sampling Techniques of FNAC
Close co-operation with ophthalmologist and radiologist and familiarity with intricate anatomy of eye is required for successful sampling.
Eye-lid Skin and Conjunctival Lesions: Routine FNAC using 23-24 G needle; combined with scrape cytology for ulcerated lesions.
Intra-Orbital Lesions: FNAC with long retrobulbar needle or lumbar puncture needle aided with ultrasonography or computed tomography guidance. Local anesthesia is required.
Intra-Ocular Lesions (excluding aqueous and vitreous): FNAC of eye is quite complex and requires specialized technique and an incision of the cornea or sclera.
(a) FNAC of Posterior Uveal Tumours:
Trans-vitreous pars plana approach: Partial thickness scleral incision given at pars plana. A flexible tube is employed between the end of 25 G 0.5 mm bore needle and a syringe attached to an aspiration pistol, thereby isolating any otherwise transmitted shake. Under direct visual control of an operating microscope and a corneal lens, needle inserted into tumour through transvitreous trans-retinal route avoiding any vessels. Small bore of needle does not cause vitreous aspiration and resultant retinal detachment. 
Direct Trans-scleral FNAC: of underlying choroidal tumour using triangular lamellar scleral flap. 
USG guided Transocular approach: -probe placed on closed eyelid at a meridian opposite to that of lesion. Needle introduced from the side opposite to that of probe. 
(b) FNAC of Anterior Uveal Tumours: USG guided paraocular approach - probe placed on closed eyelid between orbital rim and globe. Needle passed from above or from side of probe. 
(c) FNAC in Aphakik Eye : Limbal approach. 
Washings of needle in tissue culture fluid can be subjected to cytospin for making additional smears for IHC, cell button for EM and many other ancillary studies. Studies have shown that FNAC can reduce the need of intra-ocular biopsy and enucleation substantially- to fewer than 3%.  Traumatic complications produced by fine needle are infrequent and almost never serious and the concerns about tumour seeding have largely been dispelled by recent studies.
Ocular Fluid Cytology
Two chambers divide the interior of eye. Anterior aqueous chamber is located between cornea and lens, and enclosing iris within a thin fluid. Posterior chamber is located between lens and retina and filled with transparent viscous vitreous fluid (vitreous body). Exfoliated cells in these fluids can help in diagnosing inflammatory/non-neoplastic lesions as well as tumours.
Vitreous Fluid Cytology: Vitreous sample is obtained by aspiration or vitrectomy. Sample can be processed in many different ways: direct smears, Millipore filtration and cyto-centrifugation. Sample can also be processed for histology by direct paraffin embedding (of centrifuged specimen), sandwich agar technique and celloidin bag/cytoblock. Cytospin smears and cell block can be subjected to IHC, EM and FCM. ,, Cytodiagnosis of infection, hemorrhage, amyloidosis, retinal detachment and malignant tumours like lymphoma and melanoma is possible by vitreous fluid cytology. ,
Anterior Chamber Paracentesis Cytology: Anterior chamber paracentesis is a valuable procedure in the management of uveitis, particularly in diagnosing infective causes. It is also indicated in ghost-cell glaucoma, phacolytic glaucoma, epithelial downgrowth after anterior segment surgery; and suspected neoplasm (lymphoma, melanoma and retinoblastoma). ,, Needle ranging from 25 G to 30 G is used. After instilling antibiotic drops in eye, patient is positioned at slit lamp, upper lid eyelashes are held out of way by an assistant. 27 G needle is fitted to insulin syringe or aqueous pipette having a 30 G needle mounted inside plastic tubing and having a polyethylene suction-infusion bulb. This is then inserted in paralimbal clear cornea in a plane above and parallel to iris. Sample is drawn by suction of syringe or bulb under direct vision. Antibiotic drops prescribed for 3 days. Patient is re-examined after 20 minutes and 1-2 week.  Sample is immediately sent to cytology laboratory for making cytospin smears. It can be an effective and minimally invasive cytodiagnostic alternative to vitrectomy.
Need of rapid Intra-operative diagnosis arises when a definitive pre-operative diagnosis is not available or is discrepant with clinical impression. It is also used when unusual clinical presentation create a diagnostic dilemma. Intra-operative FNAC is also being used,  but as in CNS lesions, imprint and squash cytology is a better rapid intra-operative procedure for ophthalmic lesions too. ,,
Imprint Cytology: Imprint of fresh unfixed tissue or it's cut section to be preferred for large, firm or hard tissues. Smears prepared by simply touching the slides with freshly cut surface of tissue. Smears are wet fixed and stained with H and E / Papanicolaou stain or air-dried and stained with MGG/Diff-Quick.
Squash Cytology: Squash Smears are preferred for soft crushable tissue. Tiny bit of tissue (<0.1 cm), cut or teased from biopsy are placed between 2 clean slides, pressed lightly and drawn apart. Rapidity of preparation and simplicity of technique are advantages of squash techniques over frozen section. The squash technique preserves the architectural and cytological details without the intrinsic problems of frozen section artifact. 
| Tumours of Eye and Ocular Adnexa: Classification|| |
1. Tumours of the Conjunctiva
- Hereditary Benign Intraepithelial Dyskeratosis
Other Benign Epithelial Lesions: Inclusion Cysts, Leukoplakia, Pseudo-epitheliomatous Hyperplasia Conjunctival Intraepithelial Neoplasia
Squamous Cell Carcinoma and variants
Other Carcinomas: Basal Cell Carcinoma, Sebaceous Carcinoma,
Melanocytic Tumours: Nevi and variants, Melanoses, Melanoma
Soft tissue Tumours
- Embryonal Rhabdomyosarcoma, Botryoid subtype
Tumour-Like Congenital lesions : Dermoid, Dermolipoma, Hamartomas, Choristomas.
2. Tumours of Caruncle : Oncocytoma, Sebaceous gland hyperplasia, Sebaceous Carcinoma, Melanoma.
3. Tumours of Cornea : Benign Hereditary Intraepithelial dyskeratosis.
Squamous Cell Carcinoma
4. Tumours of the Uveal Tract
Melanocytic Tumours of Uvea: Nevi, Melanocytoma (Megnocellular Nevus), Malignant Melanoma, Diffuse Uveal
Non-Melanocytic Tumours of Uvea
Reactive Lymphoid Hyperplasia
Primary Non-Hodgkin's B-Cell Lymphoma Other
Secondary and Metastatic Tumours: Leukemia, Lymphoma, Plasmacytoma, Metastatic Tumours
5. Tumours of the Retina
Glial Tumours and Tumour-Like conditions: Astrocytoma, Astrocytic Hamartoma, Massive Gliosis of the Retina
Melanogenic Neuroectodermal Tumour of the Retina
Primary Intraocular Lymphoma Leukemia
Tumours of the Retinal Pigment Epithelium: Adenoma, Adenocarcinoma
Neuroepithelial Tumours: Congenital Tumours of the Ciliary Epithelium, Benign Acquired Tumours of the Ciliary Epithelium
6. Tumours of the Optic Nerve and Optic Nerve Head
Juvenile Pilocytic Astrocytoma, Malignant
Melanocytoma, Primary Malignant Melanoma
Secondary and Metastatic Tumours
7. Tumours of the Eyelids
Benign Epithelial Tumours: Squamous Cell Papilloma, Seborrheic Keratosis, Inverted Follicular keratosis, Benign Lichenoid Keratosis, Large Cell Acanthoma, Pseudocarcinomatous Hyperplasia, Keratoacanthoma
Precancerous Epithelial Lesions: Actinic Keratosis, Bowen's Disease, Radiation Dermatosis, Xeroderma Pigmentosum
Malignant Epithelial Tumours:
Basal Cell Carcinoma, and variant
Squamous Cell Carcinoma, and variant
Nevi, and variant
Malignant Melanoma, and variant
Benign Sebaceous Gland Tumours: Adenoma Adenoma of Krause's Accessory lacrimal gland
Sebaceous gland Carcinoma
Tumours of Eccrine and Apocrine Glands of the Eyelids: Syringoma, pleomorphic adenoma, Eccrine Acrospiroma, Primary Cutaneous Adenoid Cystic Carcinoma, Adenoma and Adenocarcinoma of Glands of Moll.
Tumours of the Pilar Structures of the Eyelid: trichoepithelioma, trichofolliculoma, trichilemmoma, Pilomatrixoma.
Xanthomatous Lesions: Xanthelasma, Fibrous Histiocytoma and other Lipoid Proteinosis
Cysts: Dermoid, Epidermal Inclusion, Sudoriferous (apocrine and Eccrine hydrocystoma)
Miscellaneous Lesions: Mycosis Fungoides, Granular Cell Tumour, Merkel Cell Tumour, Metastatic Tumours, and other.
8. Tumours of the Lacrimal Gland
Benign Epithelial Tumours: Pleomorphic Adenoma, Oncocytoma, Warthin's Tumour, Myoepithelioma
Malignant Epithelial Tumours: Adenoid Cystic Carcinoma, Malignant mixed Tumour, Primary Adenocarcinoma, Mucoepidermoid Carcinoma, Primary ductal Adenocarcinoma, Acinic Cell Carcinoma, Sebaceous Carcinoma.
Secondary and Metastatic Tumours
Tumour-Like Lesions: Chronic Dacryoadenitis, Benign Lympho-epithelial Lesions, Lacrimal Gland Cysts.
9. Tumours of the Lacrimal Drainage System
Epithelial Tumours (Papillomas and Carcinomas of Lacrimal Sac)
10. Tumours of the Orbit
Myogenic Tumours, including Rhabdomyo-
Peripheral Nerve Sheath Tumours
Reactive Lymphoid Hyperplasia Lymphoma
Histiocytosis: Langerhans Cell Histiocytosis Histiocytic Disorders of Mononuclear Phagocytes
Miscellaneous Orbital Tumours: Germ Cell Tumours, Choristoma, Melanoma, Carcinoid, Ewing's Sarcoma and P.N.E.T., Alveolar Soft Part Sarcoma
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N N Rai
II/5, Medical College Campus, Rangbari Road. Kota, Rajasthan 324009
Source of Support: None, Conflict of Interest: None
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