HSCT (hematopoietic stem cell transplantation) is a widely applied method of treatment of pediatric patients with leukemia and other bone marrow-associated disorders. Metabolic disturbances can appear as procedure side effects. This study aimed to report incidence of lipid and thyroid disorders and time of their onset in pediatric patients after HSCT. There were 198 pediatric patients (123 males) aged 0.5–20 years who were subjected to HSCT. Patients were mostly diagnosed with Acute Leukemia (n = 190). The analysis of lipids, thyroid hormones, and thyroid antibodies levels comprised one month before the HSCT to last follow up visit between 2016 and 2019 (median 3.8 ± 1.8 years after HSCT). In males, the triglycerides levels increased over two times in the course of HSCT in both patients with initially low and elevated HDL (high-density lipoprotein) levels. Most of the lipid disorders occurred in six months after HSCT. Patients treated with L-thyroxine exhibited decreased LDL (low-density lipoprotein) levels. HDL remained at a lower level in males. Thyroid hormone abnormalities were evenly distributed in time until 4 years after HSCT. Patients require long term follow up including lipid metabolism and thyroid function analysis. HSCT survivors demand introduction of polyunsaturated fatty acids into the diet to reduce risk of developing the lipid complications.

Multiple endocrine neoplasia 2B (MEN 2B) is a rare syndrome caused by mutation of the RET proto-oncogene. Early-onset medullary thyroid carcinoma (MTC), marfanoid habitus, and mucosal neuromas occur in most cases, and some patients develop pheochromocytoma in later life. We present a case of a 16-year-old girl diagnosed with MEN 2B syndrome with an atypical course of the disease. Our patient had no family history of MTC and presented short stature instead of marfanoid features. Rare ophthalmological manifestations also occurred. The example of this patient proves that rare endocrinological syndromes should be taken into consideration when diagnosing unclear symptoms, even if not all of the typical manifestations are present.