Korean J Pathol.  1997 Nov;31(11):1200-1213.

Immunohistochemical and Ultrastructural Observation on Small Round Cell Tumors

• Suh CH
• Yang JY
• Lim SC
• Kim YL

Abstract

Small round cell tumors such as neuroblastoma, rhabdomyosarcoma, Ewing's tumor, malignant lymphoma and small cell carcinoma are often confused clinically and histologically. To clarify the similarites and differences and to get more information on the histogenesis among the small round cell tumors, we examined histological, immunohistochemical and ultrastructural features of ten cases of neuroblastomas, twenty Ewing's tumors, ten embryonal rhabdomyosarcomas and twelve small cell carcinomas in children and young adults. Antibodies against desmin, vimentin, cytokeratin, neuron-specific enolase, synaptophysin, neurofilament, S-100 protein, chromogranin and HBA 71 were used in biotin streptavidin procedures. The results of the immunohistochemical and electron microscopical examinations yielded virtually identical findings in each group as followings. 1) Among the twenty cases of Ewing's tumors, eighteen cases were positive in staining for HBA-71. The staining for HBA-71 was negative in neuroblastoma, embryonal rhabdomyosarcoma and small cell carcinoma. 2) Neuroblastomas had marked interdigitating cytoplasmic processes containing many microtubules and dense-core secretory granules, however, they were sparse and rare in Ewing's tumor. 3) Embryonal rhabdomyosarcoma showed actin-myosin bundles. According to differentiation, well differentiated rhabdomyosarcoma exhibited Z-band materials and external lamina. 4) Neuroblastoma showed ultrastructural evidence of a neuronal differentiation, but neuronal differentration is a sparse and rare in Ewing's tumor. This ultrastructural feature strengthens the hypothesis that Ewing's tumor is derived not only from an undifferentiated neuroectodermal stem cell but from primitive cell of neuroectodermal origin.

Keyword

Small round cell tumor; Immunohistochemistry; Ultrastructure

MeSH Terms

Antibodies
Biotin
Carcinoma, Small Cell
Child
Cytoplasm
Desmin
Humans
Immunohistochemistry
Keratins
Lymphoma
Microtubules
Neural Plate
Neuroblastoma
Neurons
Phosphopyruvate Hydratase
Rhabdomyosarcoma
Rhabdomyosarcoma, Embryonal
S100 Proteins
Sarcoma, Ewing
Secretory Vesicles
Stem Cells
Streptavidin
Synaptophysin
Vimentin
Young Adult
Antibodies
Biotin
Desmin
Keratins
Phosphopyruvate Hydratase
S100 Proteins
Streptavidin
Synaptophysin
Vimentin