We review the imaging findings in pediatric thyroid diseases that necessitate prompt diagnosis and timely medical intervention. Congenital hypothyroidism particularly represents a critical pediatric emergency. Ultrasonography stands as the primary modality for accurately assessing thyroid morphology and identifying thyroid dysgenesis. ¹²³I-scintigraphy mirrors iodine metabolism and thyroid hormone synthesis, and the concurrent application of perchlorate (perchloride discharge test) elucidates the pathogenesis of thyroid dyshormonogenesis. Nonetheless, radioiodine scintigraphy has seen limited utilization due to the intricacies of pre-test preparation. ^99mTc-pertechnetate scintigraphy demonstrates high sensitivity in delineating thyroid tissues with minimal radiation exposure, facilitating the diagnosis of thyroid dysgenesis. Additionally, we have included brief insights on the imaging characteristics of central hypothyroidism, thyroiditis, and thyroid masses.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors often linked to underlying genetic variants. Genetic analysis can promote gene-adjusted, specific follow-up, and surveillance protocols for both patients and their families at risk. We report the case of a 7-yr-old boy with bilateral pheochromocytoma, which recurred a year after partial adrenalectomy. The patient’s father developed bilateral pheochromocytomas at 25 yr of age. Both individuals possessed a novel heterogeneous in-frame duplication germline variant of VHL, yet neither exhibited other clinical manifestations of von Hippel–Lindau disease (VHL). Traditionally, VHL missense mutations have been associated with a higher risk of PPGL development, whereas truncating mutations typically confer a lower risk. In-frame duplication variants are rarely observed in patients with VHL but may lead to changes in the three-dimensional structure of the translated protein, similar to truncating variants. Our analysis suggests that these in-frame duplications of amino acids in specific regions may cause pheochromocytomas in a manner similar to missense variants. Further accumulation of VHL cases with various genotypes and standardized open-access worldwide databases, including longitudinal and specific clinical data linked to genotypes, is required. It is crucial to consider genetic analyses for pediatricians who may diagnose childhood-onset PPGL.

This study aimed to examine the clinical characteristics of young children diagnosed with maturity-onset diabetes (MODY) using urine glucose screening at schools. The study participants were 70 non-obese children who were clinically diagnosed with type 2 diabetes through urine glucose screening at schools in Tokyo between 1974 and 2020. Of these children, 55 underwent genetic testing, and 21 were finally diagnosed with MODY: MODY2 in eight, MODY3 in eight, MODY1 in four and MODY5 in one. A family history of diabetes was found in 76.2% of the patients. Fasting plasma glucose levels did not differ between the different MODY subtypes, while patients with MODY 3, 1, and 5 had significantly higher levels of glycosylated hemoglobin and 2-hour glucose in an oral glucose tolerance test than those with MODY2. In contrast, most patients exhibit mild insulin resistance and sustained β-cell function. In the initial treatment, all patients with MODY2 were well controlled with diet and exercise, whereas the majority of those with MODY3, 1, and 5 required pharmacological treatment within one month of diagnosis. In conclusion, urine glucose screening in schools appears to be one of the best opportunities for early detection of the disease and providing appropriate treatment to patients.

Type 1 diabetes mellitus (T1DM) adversely affects gonadal function. This study aimed to define the characteristics and factors associated with menstrual cycle abnormalities and polycystic ovary syndrome (PCOS) in Japanese patients with T1DM. Our study enrolled 157 patients, including 55 with oligomenorrhea (prolonged menstrual cycle) and 102 without oligomenorrhea. LH/FSH ratio (p = 0.04) and total testosterone levels (p = 0.03) were significantly higher in the oligomenorrhea group than in the non-oligomenorrhea group. No significant differences were found between the two groups regarding age at menarche, age at T1DM diagnosis, treatment, glycated hemoglobin, or total daily insulin dose. Of the 55 patients in the oligomenorrhea group, 27 were diagnosed with PCOS based on the Rotterdam criteria. We concluded that female patients with T1DM, as well as abnormal menstrual cycles and hyperandrogenism, may suffer from undiagnosed PCOS and should be referred to a gynecologist for full assessment, diagnosis, and treatment.

Complete deficiency of thyroxin-binding globulin (TBG-CD) is not commonly associated with clinical symptoms, and little is known about thyroid tumors associated with TBG-CD. We present a case report of an asymptomatic follicular adenoma that spontaneously shrank in a patient with TBG-CD. A previously healthy 13-yr-old male presented with a diffusely swollen thyroid gland. Thyroid function tests revealed low total thyroxin and TBG concentrations, indicating a TBG deficiency. Ultrasonography revealed a mildly swollen thyroid gland with a nodule (14 × 12 × 19 mm) in the left lobe. Genetic analysis of peripheral blood revealed a previously reported SERPINA7 variant, which resulted in complete loss of TBG function. The nodule was identified as a follicular adenoma using fine-needle aspiration. Subsequently, the adenoma shrank without treatment. This pubertal case suggests that careful observation with ultrasonography is warranted for follicular adenoma in patients with TBG deficiency and that treatment may not be required.

Pseudoachondroplasia (PSACH) is an autosomal dominant skeletal dysplasia caused by pathogenic variants of cartilage oligomeric matrix protein (COMP). Clinical symptoms of PSACH are characterized by growth disturbances after the first year of life. These disturbances lead to severe short stature with short limbs, brachydactyly, scoliosis, joint laxity, joint pain since childhood, and a normal face. Epimetaphyseal dysplasia, shortened long bones, and short metacarpals and phalanges are common findings on radiological examination. Additionally, anterior tonguing of the vertebral bodies in the lateral view is an important finding in childhood because it is specific to PSACH and normalizes with age. Here, we report five Japanese patients with PSACH, with one recurrent (p.Cys351Tyr) and four novel heterozygous pathogenic COMP variants (p.Asp437Tyr, p.Asp446Gly, p.Asp507Tyr, and p.Asp518Val). These five pathogenic variants were located in the calcium-binding type 3 (T3) repeats. In four of the novel variants, the affected amino acid was aspartic acid, which is abundant in each of the eight T3 repeats. We describe the radiological findings of these five patients. We also retrospectively analyzed the sequential changes in the vertebral body and epimetaphysis of the long bones from the neonatal to infantile periods in a patient with PSACH and congenital heart disease.