C7 is a whole mount of the layer of flattened cells that constitutes the peritoneal lining of the coelom. Note the thin, scale-like appearance of the cells, their nuclei, cytoplasm, cell membrane, and the relative size and location of the nuclei. C6a) the use of differential interference contrast (DIC) ( Fig. In the preparation shown here, little detail is obtained using an ordinary bright field microscope ( Fig. The form and appearance of isolated squamous cells can be observed in desquamated cells from the superficial layer of the lining of the mouth ( Figs. Aggressive and neglected tumors can invade the orbit and extend partially around the eye, a circumstance that may necessitate exenteration of the orbit. Some larger tumors also exhibit ulceration or even intracorneal or intraocular invasion that can be determined by slit-lamp biomicroscopy or ultrasound biomicroscopy (UBM). Many larger tumors exhibit more than one or these clinical patterns ( Fig. 4.8.4) appears as a pink to reddish mass that exhibits prominent vascular loops internally on slit-lamp biomicroscopy. 4.8.3) appears as a translucent nodule fed and drained by prominent dilated epibulbar blood vessels. 4.8.2) is characterized by hard, white accumulation of abnormally keratinized conjunctival epithelium overlying the tumor proper. Such tumors occur in three principal clinical patterns. 2,3 It appears as a hypervascularized epibulbar tumor that is located most frequently at the limbus medially or temporally. Squamous cell carcinoma of the conjunctiva is a malignant neoplasm of the stratified squamous epithelium of the conjunctiva. Most ocular tumor specialists advise excision of conjunctival lesions suspected of being ocular surface squamous neoplasms, and surgical scraping of abnormal appearing corneal epithelium suspected of being corneal intraepithelial neoplasia with submission of the excised specimens to pathology to confirm or rule out the clinical diagnosis before initiating therapies such as topical interferon therapy or topical chemotherapy (see “ Management of Conjunctival Tumors Suspected of Being Malignant Neoplasms or Neoplasias” below). When neoplastic epithelial cells replace full-thickness conjunctival epithelium but do not invade the substantia propria, the condition is referred to as squamous cell carcinoma in situ. When malignant epithelial cells involve only a portion of the thickness of the epithelium pathologically, the condition is called conjunctival or corneal squamous epithelial dysplasia. The lesion can cause substantial impairment of visual acuity if it involves the central cornea. 1 CIN becomes evident clinically when it involves the corneal epithelium and produces a translucent whitening or graying of the involved portions of that epithelium ( Fig. These cancers range from conjunctival and corneal intraepithelial neoplasia (CIN) (essentially carcinoma in situ within the ocular surface epithelium) to nodular squamous cell carcinoma and variants thereof, including mucoepidermoid carcinoma.Ĭonjunctival/corneal intraepithelial neoplasia is a localized or diffuse replacement of normal conjunctival or corneal epithelium by malignant cells derived from the stratified squamous epithelium. The term ocular surface squamous neoplasia (OSSN) encompasses a number of related nonmelanocytic cancers that arise within the epithelium of the conjunctiva, cornea, or both. Myron Yanoff MD, in Ophthalmology, 2019 Ocular Surface Squamous Neoplasia
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