Belgorod State National Research University

Department: Pathological Anatomy.

Topic: Childhood Tumors.

Compiled by:

N. K. Gaur

Small,Round, Blue Cell Tumors in Childhood.

Primitive appearance (not anaplastic or pleomorphic)

Sheets of small,round,blue cells (with dark nuclei,scant

cytoplasm,indistinct borders.)

May show features of organogenesis specific to the tissue

of origin.

Neuroblastoma

Embryonal malignant tumour

Neural crest origin

Neoplastic neuroblasts

Site: adrenal medulla &sympathetic ganglia

7-10% of solid paediatric malignancies.

Sporadic occurance.

Rarely familial (bilateral,multifocal)

Pathology of Neuroblastoma.

Site :Paravertebral, Posterior mediastinum, abdomen ,Adrenal

1/3

Gross appearance:

Nodular, of varying size

May be encapsulated or infiltrative

Cut section: grey-tan, soft and friable

Varigated, necrosis, hemorrhage, calcification, cystic change

Microscopy of Neuroblastoma

Sheets of small, round, blue cells with dark nuclei, scant cytoplasm,

indistinct borders.

Mitosis++, Karyorrhectic debris +

Pleomorphism +/-

Homer-Wright rosettes, Neuropil.

Maturation: Schwann cell, stroma &ganglion cell differentiation.

Microscopy of Neuroblastoma.

Clinical features.

Abdominal mass, fever

Blueberry muffin

Wide metastasis

Secrete catecholamines

Vanillylmandelic acid (VMA)/Homovanillic acid (HVA) screening.

Prognosis

Stage

spread to regional lymph nodes,liver,lungs,bones etc

Age :< 1 yr.

Morphology –gangliocytic differentiation better

MYCN (N myc) gene amplification-worse.

Retinoblastoma

Malignant tumour of the eye in childhood

Neuroepithelial origin –posterior retina

Familial,- 60-70%, associated with germ line mutation, heritable.

Sporadic:30-40%,somatic gene mutation.

Associated with Rb 1 gene

Secondary malignancy –osteosarcoma

RB gene

RB gene is on chromosome 13

RB gene function is the most critical checkpoint in the cell cycle and allows the cell to enter from

G1 to S

Tumour supressor gene

If both RB genes are abnormal i.e. mutated or have a missing allele, it permits unregulated cell proliferation.

Knudson’s two-hit hypothesis

People with RB mutations are susceptibe to malignancies especially osteosarcoma

Morphology of retinoblastoma.

Gross: occular masses.

Microscopy: Sheets of small,round,blue cells with dark nuclei,scant

cytoplasm,indistinct borders

Flexner-Wintersteiner rosettes.

Morphology of retinoblastoma.

Behaviour .

Spread through optic nerve or to subarachnoid space to CNS, bone,

lymph nodes.

Cure with treatment.

Spontaneous cure.

Second malignancy.