Relevance: Peripheral primitive neuroectodermal tumor (primitive neuroectodermal tumor – PNET) belongs to the group
of malignant tumors that develop from migrating embryonic neural crest cells. PNET includes several nosological forms: Askin’s
tumor, esthesioneuroblastoma, the very peripheral primitive neuroectodermal tumor, and Ewing’s sarcoma. PNET accounts for
3–9% of all soft tissue tumors and 19% of all soft tissue sarcomas in children. In Europe and the US, PNETs account for 3.4 cases
per year per 1 million children below 15 years; in Kazakhstan – 0.6-1.2 cases per 1 million child population. Rapid tumor growth,
malignancy, and early metastasis to other organs and systems predetermine the PNET’s specific role in oncology.
The purpose of the study was to improve the quality and availability of early sarcoma diagnostics in children at medical
institutions of the general medical network.
Results: 35 cases of peripheral PNET in children were analyzed. The age of the patients was 1.5 to 17 years, the average age –
9.3 years. Boys were 1.3 times more than girls. One patient (3.6%) had extra-skeletal tumor localization. Children with stage IIB
prevailed – 46.4% of cases (13 children).
Radiographical differentiation between Ewing’s sarcoma and primary chronic or “healed” (antibiotic) acute hematogenous
osteomyelitis in the initial phase of the process is almost impossible before the extraosseous soft tissue component is formed.
The bone damage process is more often localized in the bone diaphysis and subsequently spreads to its metaphyses.
Conclusion: PNET is more likely to come from the chest wall, so it is advisable to start the X-ray examination from the chest.
In terms of radiation semiotics, PNET is similar to Ewing’s sarcoma and Askin’s tumor; therefore, an additional immunohistochemical study of the tumor tissue is required. An important indirect diagnostic criterion in Ewing’s sarcoma is the predominance of the soft tissue component over the bone manifestations. Extended CT and MRI studies with contrast enhancement
(chest, abdominal cavity, pelvis, and the primary lesion area) and skeletal scintigraphy are required to clarify the extent of
changes, stage the tumor accurately, and assess the tumor dynamics after treatment. The above conclusions generally confirm
the available literature data.
Radiation Therapy (RT) target determination for irradiation of bone metastases with soft tissue component: Impact of multimodality imaging
