Purpose: Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH. Methods: This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups. Results: Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH. Conclusion The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

Purpose: Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH. Methods: This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups. Results: Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH. Conclusion The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that mainly occur in the stomach and small intestine; those arising in the esophagus are rarer. A 54-year-old woman was referred to our hospital with a one-month history of dysphagia. Esophagogastroduodenoscopy (EGD), performed approximately five months earlier, had not revealed any specific findings. However, an EGD performed in our hospital showed the presence of a round, protruding lesion (approximately 40×30 mm in size), with a normal overlying mucosal surface, 35–39 cm from the upper incisor. Chest computed tomography (CT) revealed a large esophageal mass. Enucleation was performed on the esophageal mass, and a GIST was diagnosed using immunochemical staining. Imatinib mesylate administration was initiated two months postoperatively. The patient was stable, without any evident recurrence in the 8-month postoperative follow-up EGD and chest CT examinations. Therefore, physicians should consider that patients with worsening dysphagia may have an underlying organic condition, such as an acute increase in size of an esophageal GIST, even if recent examinations were unremarkable.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that mainly occur in the stomach and small intestine; those arising in the esophagus are rarer. A 54-year-old woman was referred to our hospital with a one-month history of dysphagia. Esophagogastroduodenoscopy (EGD), performed approximately five months earlier, had not revealed any specific findings. However, an EGD performed in our hospital showed the presence of a round, protruding lesion (approximately 40×30 mm in size), with a normal overlying mucosal surface, 35–39 cm from the upper incisor. Chest computed tomography (CT) revealed a large esophageal mass. Enucleation was performed on the esophageal mass, and a GIST was diagnosed using immunochemical staining. Imatinib mesylate administration was initiated two months postoperatively. The patient was stable, without any evident recurrence in the 8-month postoperative follow-up EGD and chest CT examinations. Therefore, physicians should consider that patients with worsening dysphagia may have an underlying organic condition, such as an acute increase in size of an esophageal GIST, even if recent examinations were unremarkable.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that mainly occur in the stomach and small intestine; those arising in the esophagus are rarer. A 54-year-old woman was referred to our hospital with a one-month history of dysphagia. Esophagogastroduodenoscopy (EGD), performed approximately five months earlier, had not revealed any specific findings. However, an EGD performed in our hospital showed the presence of a round, protruding lesion (approximately 40×30 mm in size), with a normal overlying mucosal surface, 35–39 cm from the upper incisor. Chest computed tomography (CT) revealed a large esophageal mass. Enucleation was performed on the esophageal mass, and a GIST was diagnosed using immunochemical staining. Imatinib mesylate administration was initiated two months postoperatively. The patient was stable, without any evident recurrence in the 8-month postoperative follow-up EGD and chest CT examinations. Therefore, physicians should consider that patients with worsening dysphagia may have an underlying organic condition, such as an acute increase in size of an esophageal GIST, even if recent examinations were unremarkable.

Purpose: Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH. Methods: This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups. Results: Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH. Conclusion The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

Purpose: 46,XX disorders of sex development (DSD) involve atypical genitalia accompanied by a normal female karyotype. This study was performed to investigate the clinical characteristics and long-term outcomes of patients with 46,XX DSD. Methods: The study included 34 patients with 46,XX DSD who presented with ambiguous genitalia or delayed puberty. Patients with congenital adrenal hyperplasia were excluded. Clinical phenotypes and overall outcomes were analyzed retrospectively. Results: Age at presentation ranged from birth to 40 years (median, 0.6 years), and the follow-up period ranged from 0.3 to 29.7 years (median, 8.8 years). Twenty patients were assigned female (58.8%). Etiologies included disorders of gonadal development (n=22), exogenous androgen exposure during pregnancy (n=5), association with syndromic disorders or genital anomalies (n=2), and unclassified causes (n=5). Ovotestis was the most frequent gonadal pathology (41.7%). Müllerian duct remnants were usually underdeveloped (52.9%) or absent (23.5%). Spontaneous puberty occurred in 17 of the 21 patients of pubertal age, while 9 patients required sex hormone replacement therapy. Gonadal complications were observed in 4 patients (gonadal tumors [n=3], and spontaneous gonadal rupture [n=1]), and gender dysphoria occurred in 1 patient who was assigned male. Conclusion This study described the wide phenotypic spectrum and pubertal outcome of patients with 46,XX DSD. Long-term multidisciplinary monitoring for pubertal development, fertility, gender identity, and gonadal complications is recommended.

Purpose: Congenital hypothyroidism (CH) is a major preventable cause of intellectual disability, particularly in very low birth weight (VLBW) infants, who are at increased risk due to hypothalamic-pituitary-thyroid axis immaturity. Early differentiation between transient CH (TCH) and permanent CH (PCH) is crucial to optimize L-thyroxine (LT4) treatment duration. This study aimed to determine the incidence of PCH among Korean VLBW infants and to identify clinical factors that may aid in distinguishing TCH from PCH. Methods: This retrospective cohort study included VLBW infants diagnosed with CH and treated with LT4 at a single tertiary neonatal intensive care unit between 2011 and 2020. Infants requiring LT4 beyond 3 years were classified as PCH, while those who discontinued earlier were considered TCH. Clinical characteristics, neonatal morbidities, and thyroid-related parameters were compared between the groups. Results: Among 1,292 VLBW infants, 122 (9.4%) were diagnosed with CH. After excluding deaths and those lost to follow-up, 73 infants were included in the final analysis (TCH, n=50; PCH, n=23). The PCH group had a significantly higher mean gestational age and greater LT4 requirements at both 12 and 36 months of age. Major anomalies were more frequently observed in PCH infants, including congenital heart defects. In multivariate analysis, higher gestational age, the presence of major anomalies, screening thyroid-stimulating hormone (TSH) >10 μIU/mL, and higher LT4 dose at 36 months were significantly associated with PCH. Conclusion The incidence of PCH in Korean VLBW infants was relatively higher than that reported in previous studies studies. Screening TSH level and LT4 dose requirements may support individualized follow-up and help distinguish PCH from TCH.

Purpose: 46,XX disorders of sex development (DSD) involve atypical genitalia accompanied by a normal female karyotype. This study was performed to investigate the clinical characteristics and long-term outcomes of patients with 46,XX DSD. Methods: The study included 34 patients with 46,XX DSD who presented with ambiguous genitalia or delayed puberty. Patients with congenital adrenal hyperplasia were excluded. Clinical phenotypes and overall outcomes were analyzed retrospectively. Results: Age at presentation ranged from birth to 40 years (median, 0.6 years), and the follow-up period ranged from 0.3 to 29.7 years (median, 8.8 years). Twenty patients were assigned female (58.8%). Etiologies included disorders of gonadal development (n=22), exogenous androgen exposure during pregnancy (n=5), association with syndromic disorders or genital anomalies (n=2), and unclassified causes (n=5). Ovotestis was the most frequent gonadal pathology (41.7%). Müllerian duct remnants were usually underdeveloped (52.9%) or absent (23.5%). Spontaneous puberty occurred in 17 of the 21 patients of pubertal age, while 9 patients required sex hormone replacement therapy. Gonadal complications were observed in 4 patients (gonadal tumors [n=3], and spontaneous gonadal rupture [n=1]), and gender dysphoria occurred in 1 patient who was assigned male. Conclusion This study described the wide phenotypic spectrum and pubertal outcome of patients with 46,XX DSD. Long-term multidisciplinary monitoring for pubertal development, fertility, gender identity, and gonadal complications is recommended.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that mainly occur in the stomach and small intestine; those arising in the esophagus are rarer. A 54-year-old woman was referred to our hospital with a one-month history of dysphagia. Esophagogastroduodenoscopy (EGD), performed approximately five months earlier, had not revealed any specific findings. However, an EGD performed in our hospital showed the presence of a round, protruding lesion (approximately 40×30 mm in size), with a normal overlying mucosal surface, 35–39 cm from the upper incisor. Chest computed tomography (CT) revealed a large esophageal mass. Enucleation was performed on the esophageal mass, and a GIST was diagnosed using immunochemical staining. Imatinib mesylate administration was initiated two months postoperatively. The patient was stable, without any evident recurrence in the 8-month postoperative follow-up EGD and chest CT examinations. Therefore, physicians should consider that patients with worsening dysphagia may have an underlying organic condition, such as an acute increase in size of an esophageal GIST, even if recent examinations were unremarkable.