Radiation diagnosis of peripheral
 primitive neuroectodermal tumors
 (PNET) in children under
 the conditions of the scientific center of
 pediatrics and pediatric surgery
 (Almaty, Kazakhstan)

Abstract

Relevance: Peripheral 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 [1]. PNET accounts
 for 3–9% of all soft tissue tumors and 19% of all soft tissue
 sarcomas in children [2, 3]. 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 [4].
 The purpose was to improve the quality and availability of early sarcoma diagnostics in children in 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 originates most often 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 coincide with the available literature data.