Page 225 - Concise Pathology for Exam Preparation ( PDFDrive )

210 SECTION I General Pathology

Staging

• Stage 1: Localized tumour that is completely surgically removed at diagnosis.
• Stage 2A: Unilateral tumour with incomplete gross resection; identifiable, ipsilateral and
contralateral lymph nodes negative for tumour.
• Stage 2B: Localized tumour with or without complete gross resection; representative
ipsilateral nonadherent lymph nodes positive for tumour; enlarged contralateral lymph
nodes are negative for tumour microscopically.
• Stage 3: Unresectable unilateral tumour infiltrating across the midline with or without
lymph nodes involvement or localized unilateral tumour with contralateral regional
lymph nodes involvement.
• Stage 4: Any primary tumour with dissemination to distant lymph nodes, bone, bone
marrow, liver, skin or other organs except defined for stage 4s.
• Stage 4s: Localized primary tumour (as defined for stages 1, 2A or 2B) with
dissemination limited to skin, liver and/or bone marrow (less than 10% of nucleated
cells are constituted by the neoplastic cells; more than 10% involvement of bone
marrow is considered stage 4).

Q. Describe the clinicopathological features of retinoblastoma.
Ans. Retinoblastoma is the most common malignant tumour of the eye in childhood.
• It frequently occurs as a congenital tumour.
• About 60–70% of the tumours are associated with a germline mutation in the RB1 gene
and are inherited; 30–40% of the tumours develop sporadically and have a somatic RB1
gene mutation.
• Occurs in both familial (may be multifocal and bilateral) and sporadic patterns.
• May undergo spontaneous regression.
• Patients have a high incidence of secondary tumours. (Patients with familial retinoblastoma
are at increased risk of developing osteosarcoma and other soft-tissue sarcomas.)
• Most cases are diagnosed before the age of 4 years.

Clinical Features

• Median age at presentation is 2 years.
• Presenting findings include poor vision, strabismus, a whitish hue to the pupil
(cat’s eye reflex) and pain in the eye.

Morphology
• Arises from neuroepithelial cells.
• Nodular, often with satellite lesions.
• Composed of small round cells with hyperchromatic nuclei and scant cytoplasm (resembling
retinoblasts).
• True rosettes called Flexner–Wintersteiner rosettes (clusters of cuboidal or short
columnar cells arranged around a central lumen, which seems to have a limiting
membrane resembling the external limiting membrane of the retina) are present and are
unlike the pseudorosettes of neuroblastoma, which lack a true lumen.
• Tumour cells spread along the optic nerve or subarachnoid space.
• Distant metastases is seen in CNS, skull, distal bones and lymph nodes.

Prognosis

Untreated the tumour is fatal, but with enucleation, chemotherapy and radiotherapy, sur-
vival rates are usually good.

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