Ocular Pathology Flashcards
What is proptosis and what conditions can cause it?
Proptosis is the displacement of the eye forward; conditions causing it include enlargement of the lacrimal gland, tumors (lymphoma, glioma, meningioma), and thyroid ophthalmopathy (Graves disease).
What are the potential complications of proptosis regarding the eye?
The proptotic eye may not be fully covered by the eyelids, leading to exposure, ulceration, and infection.
What is the most common neoplasm of the eyelid?
Basal cell carcinoma.
What are some other neoplasms of the eyelid?
Sebaceous carcinoma and Kaposi sarcoma.
What are the benign lesions of the conjunctiva?
Papilloma and nevi.
What are the malignant lesions of the conjunctiva?
Squamous intraepithelial neoplasia, squamous cell carcinoma, melanoma, mucoepidermoid carcinoma.
What is the most common intraocular malignancy of adults and where does it typically metastasize?
Metastasis to the uvea, typically to the choroid.
From which organs do metastases to the uvea commonly originate?
Commonly from the breast, lung, kidney, and gastrointestinal tract; worst prognosis from the pancreas.
What is the most common primary intraocular malignancy of adults?
Uveal melanoma.
Which oncogenes are most important in the pathogenesis of uveal melanoma?
GNAQ and GNA11 oncogenes.
How do mutations in GNAQ and GNA11 contribute to uveal melanoma?
Gain-of-function mutations in these genes activate pathways like the MAPK pathway that promote proliferation.
What genetic deletion is implicated in uveal melanoma and what is its significance?
Loss of chromosome 3 leads to deletion of BAP1, a tumor suppressor gene.
What are the clinical features of uveal melanoma?
Clinical features include symptoms related to glaucoma or retinal detachment.
How do uveal melanomas spread and where do they primarily metastasize?
They spread almost exclusively by the hematogenous route, primarily metastasizing to the liver.
What is the most common primary intraocular malignancy of children?
Retinoblastoma.
What is the cell of origin for retinoblastoma?
Neuronal progenitor cell.
How is retinoblastoma classified?
Heritable and non-heritable forms.
What is the typical form of inheritance for bilateral retinoblastoma?
Most bilateral cases are heritable.
What is the two-hit model of carcinogenesis as it relates to retinoblastoma?
Both alleles need to be affected; the first mutational event can be inherited and is present in all body cells, while the second occurs in a retinal cell.
How do sporadic forms of retinoblastoma develop?
Both mutational events occur within a single retinal cell after fertilization.
What is trilateral retinoblastoma?
Inherited unilateral or bilateral retinoblastoma plus pinealoblastoma and/or primitive neuroectodermal tumor (PNET).
On which chromosome is the retinoblastoma gene located?
Chromosome 13q14.
What is the function of the RB gene?
It is a tumor suppressor gene that binds and inactivates E2F transcription factor, suppressing S phase gene transcription.
How does MYCN contribute to retinoblastoma?
MYCN can act as a transcription factor and promote proliferation; its amplification accounts for about 1.4% of retinoblastoma cases.
What are the characteristics of MYCN-amplified retinoblastoma?
Early-onset, unilateral, aggressive retinoblastoma; median age of diagnosis is 4.5 months compared to 24 months for nonfamilial, unilateral retinoblastoma.
What are the clinical features of retinoblastoma?
Leukocoria, strabismus, proptosis, poor vision, glaucoma.
What are Flexner-Wintersteiner rosettes and Homer Wright rosettes?
Flexner-Wintersteiner rosettes have a clear space at the center, while Homer Wright rosettes have neuropil at the center.
What is the significance of necrosis and optic nerve extension in retinoblastoma?
Necrosis and optic nerve extension indicate advanced disease.
How can retinoblastoma be managed if detected early?
Early detection can lead to cure.
What are the treatment options for retinoblastoma?
Chemotherapy for globe preservation, enucleation, and external beam radiotherapy.
What are the preferred sites for basal cell carcinoma metastases?
Lymph nodes, lungs, bones.
What is a common clinical feature of melanoma found in the eye?
Leukocoria (white light reflection by the tumor).
What are the most significant risk factors for squamous cell carcinoma of the conjunctiva?
Sun exposure and immunosuppression.
How do squamous cell carcinomas of the conjunctiva typically present?
As erythematous scaly patches or nodules.
What is the role of HPV in conjunctival papilloma?
Associated with HPV 16/18.
What is the prognosis for mucoepidermoid carcinoma of the conjunctiva?
Poor due to aggressive nature and easy spread.
How does the loss of chromosome 3 affect uveal melanoma progression?
Leads to deletion of BAP1, contributing to tumor progression.
What are the histological characteristics of uveal melanoma?
Histologically, they contain both spindle and epithelioid cells.
How does the hematogenous spread of uveal melanoma typically occur?
Through the bloodstream.
What is the most common presenting symptom of retinoblastoma?
Leukocoria.
What are the differences in presentation between hereditary and nonhereditary retinoblastoma?
Hereditary retinoblastoma often presents bilaterally, while nonhereditary presents unilaterally.
