Ocular Pathology

Question 1

What is proptosis and what conditions can cause it?

Answer 1

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).

Question 2

What are the potential complications of proptosis regarding the eye?

Answer 2

The proptotic eye may not be fully covered by the eyelids, leading to exposure, ulceration, and infection.

Question 3

What is the most common neoplasm of the eyelid?

Answer 3

Basal cell carcinoma.

Question 4

What are some other neoplasms of the eyelid?

Answer 4

Sebaceous carcinoma and Kaposi sarcoma.

Question 5

What are the benign lesions of the conjunctiva?

Answer 5

Papilloma and nevi.

Question 6

What are the malignant lesions of the conjunctiva?

Answer 6

Squamous intraepithelial neoplasia, squamous cell carcinoma, melanoma, mucoepidermoid carcinoma.

Question 7

What is the most common intraocular malignancy of adults and where does it typically metastasize?

Answer 7

Metastasis to the uvea, typically to the choroid.

Question 8

From which organs do metastases to the uvea commonly originate?

Answer 8

Commonly from the breast, lung, kidney, and gastrointestinal tract; worst prognosis from the pancreas.

Question 9

What is the most common primary intraocular malignancy of adults?

Answer 9

Uveal melanoma.

Question 10

Which oncogenes are most important in the pathogenesis of uveal melanoma?

Answer 10

GNAQ and GNA11 oncogenes.

Question 11

How do mutations in GNAQ and GNA11 contribute to uveal melanoma?

Answer 11

Gain-of-function mutations in these genes activate pathways like the MAPK pathway that promote proliferation.

Question 12

What genetic deletion is implicated in uveal melanoma and what is its significance?

Answer 12

Loss of chromosome 3 leads to deletion of BAP1, a tumor suppressor gene.

Question 13

What are the clinical features of uveal melanoma?

Answer 13

Clinical features include symptoms related to glaucoma or retinal detachment.

Question 14

How do uveal melanomas spread and where do they primarily metastasize?

Answer 14

They spread almost exclusively by the hematogenous route, primarily metastasizing to the liver.

Question 15

What is the most common primary intraocular malignancy of children?

Answer 15

Retinoblastoma.

Question 16

What is the cell of origin for retinoblastoma?

Answer 16

Neuronal progenitor cell.

Question 17

How is retinoblastoma classified?

Answer 17

Heritable and non-heritable forms.

Question 18

What is the typical form of inheritance for bilateral retinoblastoma?

Answer 18

Most bilateral cases are heritable.

Question 19

What is the two-hit model of carcinogenesis as it relates to retinoblastoma?

Answer 19

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.

Question 20

How do sporadic forms of retinoblastoma develop?

Answer 20

Both mutational events occur within a single retinal cell after fertilization.

Question 21

What is trilateral retinoblastoma?

Answer 21

Inherited unilateral or bilateral retinoblastoma plus pinealoblastoma and/or primitive neuroectodermal tumor (PNET).

Question 22

On which chromosome is the retinoblastoma gene located?

Answer 22

Chromosome 13q14.

Question 23

What is the function of the RB gene?

Answer 23

It is a tumor suppressor gene that binds and inactivates E2F transcription factor, suppressing S phase gene transcription.

Question 24

How does MYCN contribute to retinoblastoma?

Answer 24

MYCN can act as a transcription factor and promote proliferation; its amplification accounts for about 1.4% of retinoblastoma cases.

Question 25

What are the characteristics of MYCN-amplified retinoblastoma?

Answer 25

Early-onset, unilateral, aggressive retinoblastoma; median age of diagnosis is 4.5 months compared to 24 months for nonfamilial, unilateral retinoblastoma.

Question 26

What are the clinical features of retinoblastoma?

Answer 26

Leukocoria, strabismus, proptosis, poor vision, glaucoma.

Question 27

What are Flexner-Wintersteiner rosettes and Homer Wright rosettes?

Answer 27

Flexner-Wintersteiner rosettes have a clear space at the center, while Homer Wright rosettes have neuropil at the center.

Question 28

What is the significance of necrosis and optic nerve extension in retinoblastoma?

Answer 28

Necrosis and optic nerve extension indicate advanced disease.

Question 29

How can retinoblastoma be managed if detected early?

Answer 29

Early detection can lead to cure.

Question 30

What are the treatment options for retinoblastoma?

Answer 30

Chemotherapy for globe preservation, enucleation, and external beam radiotherapy.

Question 31

What are the preferred sites for basal cell carcinoma metastases?

Answer 31

Lymph nodes, lungs, bones.

Question 32

What is a common clinical feature of melanoma found in the eye?

Answer 32

Leukocoria (white light reflection by the tumor).

Question 33

What are the most significant risk factors for squamous cell carcinoma of the conjunctiva?

Answer 33

Sun exposure and immunosuppression.

Question 34

How do squamous cell carcinomas of the conjunctiva typically present?

Answer 34

As erythematous scaly patches or nodules.

Question 35

What is the role of HPV in conjunctival papilloma?

Answer 35

Associated with HPV 16/18.

Question 36

What is the prognosis for mucoepidermoid carcinoma of the conjunctiva?

Answer 36

Poor due to aggressive nature and easy spread.

Question 37

How does the loss of chromosome 3 affect uveal melanoma progression?

Answer 37

Leads to deletion of BAP1, contributing to tumor progression.

Question 38

What are the histological characteristics of uveal melanoma?

Answer 38

Histologically, they contain both spindle and epithelioid cells.

Question 39

How does the hematogenous spread of uveal melanoma typically occur?

Answer 39

Through the bloodstream.

Question 40

What is the most common presenting symptom of retinoblastoma?

Answer 40

Leukocoria.

Question 41

What are the differences in presentation between hereditary and nonhereditary retinoblastoma?

Answer 41

Hereditary retinoblastoma often presents bilaterally, while nonhereditary presents unilaterally.