Mihail Parnov

One controversial issue in pituitary pathology is the simultaneous proliferation of PitNETs and endothelial cells. No previous studies have compared the MIB1 Labeling Index (MIB1 LI) of PitNETs and stromal endothelial compartments and its connection with VEGF protein and gene expression. Simultaneous PitNETs proliferation index assessment in tumor and endothelial cells is related to VEGF protein and gene expression, and by using the automated QuPath platform for digital image analysis (DIA), it can be determined whether this dual proliferation specifically characterizes certain PitNETs subtypes. A total of 109 PitNETs were immunostained for endothelial cells (CD34) and proliferation (MIB1). VEGF was assessed by using IHC and RNA scopes. QuPath_DIA measured hormone-dependent MIB1 nuclear expression in tumor and stromal endothelial cells. MIB1 LI correlated with VEGF_mRNA and protein expression. PRL-secreting and non-functioning PitNETs had a high MIB1 LI in stromal endothelial cells. MIB1-positive tumor cell (%MIB1 LI.T) and endothelial cell (%MIB1 LI.E) percentages were substantially correlated (p = 0.01). The profiles of VEGF and hormones significantly and heterogeneously impact the MIB1-LI of tumor and endothelial cells. Tumor–endothelial cell proliferative interaction is specific to PRL-secreting and non-functioning PitNETs. These findings suggest that digital analysis of MIB1 and VEGF expression may serve as a valuable tool for risk stratification in PitNETs.

Infantile hemangiomas are the most common benign vascular tumors of childhood, with a high incidence in the neonatal period, especially in preterm infants. Although typically self-limiting, their etiopathogenesis remains incompletely understood, involving genetic, epigenetic, and perinatal factors (e.g., hypoxia, prematurity). A placental origin of the endothelial tumor cells is supported by immunophenotypic similarities to placental vessels and consistent GLUT-1 expression. The immunohistochemical profile varies depending on the evolutionary phase: the proliferative phase shows predominant expression of VEGF, PCNA, CD31, and CD34; the involutive and involuted phases are marked by regressive changes, including apoptosis, hyalinization, and adipocytic transformation. These differential markers are useful in distinguishing infantile hemangiomas from other benign or malignant vascular entities. Detailed histopathological examination and identification of key immunohistochemical markers remain essential for accurate diagnosis, classification, and treatment planning in infantile hemangiomas.

The pituitary gland is a key endocrine organ involved in the regulation of neuroendocrine functions. However, its morphology during childhood remains poorly documented, with fragmented data in the worlwide literature and almost no studies in the local context. This paper aims to analyze morphological aspects of the infant pituitary gland by correlating existing literature data with histological observations from a series of pediatric autopsy cases. Morphological analysis was performed on standard hematoxylin and eosin-stained sections. Changes observed in both the adenohypophysis and neurohypophysis are described, highlighting structural particularities during the neonatal period. The study provides preliminary observations regarding cellular distribution, tissue maturation, and potential influences of neonatal pathology on pituitary architecture. The conclusions contribute to a better understanding of normal pituitary development and possible morphological deviations during childhood.