The detection of an intraocular embryonic tumor – retinoblastoma (RB) – in children and its differential diagnosis with diseases mimicking RB is an important task of imaging. Considering that the clinical and radiological patterns of RB and the diseases mimicking it may be similar, and the choice of a treatment strategy is carried out without preliminary histological examination, the primary diagnosis is of decisive importance. A comprehensive diagnostic approach for suspected RB provides a timely choice of optimal treatment tactics and improves prognosis. The article presents the most demonstrative own observations. The literature review includes the modern possibilities of non-ionizing radiation diagnostics of RB and diseases mimicking as it.

Relevance. Autologous hematopoietic stem cell transplantation (auto-HSCT) is an integral part of the treatment of patients with high-risk malignancies. However, carrying out the mobilization and collection of hematopoietic stem cells (HSC) for patients weighing up to 15 kg is a complex task that requires a special approach and multidisciplinary interaction.

The purpose of the study is to present the experience of collecting HSC in young children weighing up to 15 kg at the Research Institute of Pediatric Oncology and Hematology of the Federal State Budgetary Institution N.N. Blokhin National Medical Research Centre of Oncology, Ministry of Health of Russia.

Materials and methods. The study included 30 patients weighing up to 15 kg who received treatment from January 2020 to May 2021 at the Research Institute of Pediatric Oncology and Hematology of the Federal State Budgetary Institution N.N. Blokhin National Medical Research Centre of Oncology, Ministry of Health of Russia. Median age was 30.6 (12–48) months, median body weight was 12.2 (7.8–15) kg. Apheresis in children weighing up to 15 kg was performed in the resuscitation and intensive care unit with the condition of pre-filling the cell separator circuit with a donor irradiated erythrocyte suspension to prevent hypovolemic complications. Thirty two apheresis was performed on a cell separator of the “Spectra Optia” type. To mobilize HSC, preparations of granulocyte colony-stimulating factor with the main active ingredient filgrastim were used.

Results. Twenty eight HSC apheresis procedures were successful on the first attempt, 2 patients underwent repeated apheresis (a total of 32 procedures were performed). The median number of CD34⁺ cells obtained was 13.9 × 10⁶/kg (0.04–92.0 × 10⁶/kg), and the median apheresis duration was 251 (160–415) min. In 2 children during the procedure, an immediate organization of repeated venous access was required.

Conclusions. Performing HSC apheresis in children weighing up to 15 kg and young children is a safe and effective technique with the participation of a multidisciplinary team. The apheresis algorithm proposed by us makes it possible to carry out a high-quality collection of CD34⁺ cells, sufficient for auto-HSCT.

PIK3CA-Related Overgrowth Spectrum (PROS) refers to rare syndromes, which are characterized by malformations and excessive tissue growth and caused by somatic mutations in the PIK3CA gene occurring during embryogenesis. This article discusses the pathogenesis, clinical picture, diagnosis and treatment of these syndromes.

Some of the illustrations used in this article are copied from other resources, the rights of the authors are respected and not violated. The appropriate permissions from the journals have been obtained.

Post-thrombotic syndrome (PTS) is a long-term consequence of deep vein thrombosis. The development of PTS leads to the loss of venous access, cosmetic defects and poor quality of life due to restrictions in physical and/or daily activities. The review contains data on the prevalence, pathogenesis, prognostic factors and evaluation of PTS. Understanding the occurrence and prevention is very serious because if PTS develops after deep vein thrombosis, children can suffer from various physical and social consequences that may last for many years. The review contains data on the prevalence, pathogenesis, risk factors and diagnosis of PTS.

Fibrous hamartoma of infancy (FHI) is a rare tumor, accounting for less than 2% of soft tissue tumors occurring in the first year of life. The tumor arises from the subcutaneous tissue and is most often found in the armpit, then in the shoulder, groin and chest wall. The characteristic microscopic appearance of FHI is the presence of three tissue types in varying proportions: well-defined bundles of dense fibrous connective tissue, primitive mesenchyme (organized in nests, concentric whorls, or bands), and intermediate mature adipose tissue. Surgical removal is the main choice of treatment for this pathology. We report 2 cases of rare FHI localized in the gluteal region and the region of the posterior upper third of the thigh. At the same time, in one observation, the lesion affected only the subcutaneous fat, and in the second, a widespread invasive process in the muscles was noted. Despite the benign nature of the tumor, its spread is characterized by invasive growth (it does not have a capsule and a clear border with the surrounding tissues), which can cause difficulties for surgeons during the primary operation in determining the boundaries of FHI removal. For this purpose, we consider it expedient to use an express biopsy during surgery.

Melanotic neuroectodermal tumor (MNET) of infants is a rare benign neoplasm detected mainly in children of the first year of life. Standard therapy consists of radical surgical removal of the tumor. Currently, the treatment of patients with recurrent and unresectable forms of the disease is relevant. The number of publications using polychemotherapy and radiation therapy is extremely limited. This article describes a clinical case of the occurrence of MNET in the anterior fontanel with a recurrent course. Proton radiation therapy was chosen as an alternative treatment method.