Immunoglobulin G4-related disease (IgG4-RD) is a lymphoproliferative disease which is described almost exclusively in adults. There are only a few pediatric patients who have been observed with this disorder. Here, we describe a rare case of IgG4-RD in a 17-year-old girl with a single manifestation—tracheal stenosis without previous intubation or other inciting event. She had mixed dyspnea and noisy and weakened breathing. Immunoproliferative hyper-IgG4 disease was diagnosed, based on elevated serum IgG4 and histological findings. Until now we have chosen to treat the girl only with corticosteroids with a good response so far. The general condition as well as the respiratory function are regularly monitored. The tracheal involvement of IgG4-RD is uncommon. Nonetheless, it is a manifestation that should be included in the differential diagnosis of tracheal stenosis.

Recently, there has been increased awareness of the global burden of tuberculosis in children, resulting in more attention being given to pediatric tuberculosis from a clinical, public health, and research perspective.^1,2,7-11 Improving the accuracy of the diagnosis of tuberculosis in children is made more difficult by the paucibacillary nature of their disease; the fact that the symptoms and signs they present, as well as the radiological findings, are often nonspecific; and the inability of immunodiagnostic tests (interferon-gamma release assays and tuberculin skin tests) to differentiate between infection with Mycobacterium tuberculosis and active disease. Expanding the evidence available in the scientific literature to support quality diagnostic and treatment guidelines specific to pediatrics is a core issue,^1,2,7-11 as is the need to increase the availability of the child-friendly drug formulations that are now available through the Global Drug Facility of the international Stop TB Partnership.¹²

Background: Each year, approximately two million adolescents and young adults in the world become infected with tuberculosis (TB). The problem is that the classification of the disease includes children in the age group 0–14 years and young adults aged 15 and over. The present study aims to analyze and compare the epidemiology and clinical presentation of TB in Bulgaria in the different age subgroups of childhood. Methods: A retrospective study was undertaken of the newly diagnosed children (n = 80) with TB treated onsite from January 2018 to December 2020 at the Multiprofile Hospital for Active Treatment of Pulmonary Diseases (“St. Sofia”). They were distributed into three age groups: aged 8–11 (prepuberty), aged 12–14 (younger adolescents), and aged above 15 (older adolescents). Results: A clear finding of the research indicated that adolescent children develop TB both as primary and secondary infections. In a large number of cases with the children under our care, we found enlarged intrathoracic lymph nodes as well as infiltrative changes in the lungs, i.e., we observed transitional forms. There were statistically significant differences between the age group >15 years old and each of the other two younger groups for diagnosis, the severity of intoxication, and BK spreading status. Conclusion: The course of tuberculosis in adolescence has its own specifics and differences between the three age groups in the current study.

Invasive Mucormycosis (IM) is an extremely rare infection with a high mortality rate, caused by a group of fungi classified as Mucorales moulds. Rhizomucor pusillus is a saprophitic, thermophilic, and angioinvasive microorganism that grows and lives at about 45 °C and is usually found in different environmental spaces such as soil, air, water, food, and other organic matter. These features predispose the infection to wide dissemination, especially in immunocompromised patients and most often in children after chemotherapy for hematological malignancies (HMs). Mucormycosis in patients with hematologic malignancies and neutropenia represents between 0.07% and 4.29% of the concomitant diseases. IM can develop into an infection in different sites, but its most common manifestation is pulmonary, followed by rhino-orbital–cerebral and disseminated forms. In recent years, an increased morbidity rate has been associated with the ongoing COVID-19 pandemic, as cited in the literature. There are many publications with COVID-19-associated mucormycosis (CAM) cases. The present treatment protocol includes extensive and radical surgical debridement and systemic antifungal therapy with Liposomal Amphotericin B (L-AmB), Posaconazole, and Isavuconazole, either combined or as monotherapy. Despite these new treatment modalities, the mortality rate remains over 50%. We present a rare case of a 3-year-old child with acute lymphoblastic leukemia (ALL) and systemic Rhizomucor pusillus infection, diagnosed on the occasion of lung and brain abscesses. The patient underwent lung and brain surgery and is recovering well with no further complications. The two-year follow-up period shows no signs of recurrence of the disease.