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 1/3Gross appearance:Nodular, of varying sizeMay be encapsulated or infiltrativeCut 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.