Primary malignant mediastinal germ cell tumors (GCTs) are rare pediatric tumors that have a poorer prognosis than GCTs occurring elsewhere in the body. Due to their rarity and aggressiveness, they are often locally advanced and unresectable at diagnosis, and currently, there is no standard optimal treatment approach. Herein, we present a rare case of pediatric anterior mediastinal yolk sac tumor (YST) diagnosed as pathological complete response (CR) to chemotherapy but prematurely required pulmonary metastasectomy of mixed GCT consisting of seminoma and YST. Testicular GCTs can relapse as tumors of subtypes that are pathologically different from the primary tumor, each having distinct pathogenesis, treatment modality, and prognosis; however, this phenomenon is seldom reported in mediastinal GCTs. This report reviewed the discordance of histological composition between primary and metastatic tumors. When treating mediastinal nonseminomatous GCTs, the possibility of early recurrence should be considered, even if the primary tumor is completely resected and diagnosed as pathological CR to chemotherapy.

BackgroundAplasia cutis congenita (ACC) is a rare developmental anomaly characterized by the absence of skin at birth. Type V ACC is a distinct subtype associated with fetus papyraceus—the compressed remnant of a deceased co‐twin—and typically manifests as symmetrical, linear, or stellate lesions involving the trunk and proximal extremities. The proposed mechanism involves ischemic or thromboembolic injury to the surviving twin due to shared placental circulation.Case PresentationWe describe a 30‐day‐old female neonate, the surviving twin of a dichorionic gestation, whose co‐twin was delivered as a fetus papyraceus. The patient presented with extensive, bilaterally symmetrical, linear, and plaque‐like areas of absent skin involving the anterior and posterior trunk. No scalp, limb, or mucosal involvement was observed. Systemic examination and laboratory workup were unremarkable. Based on the characteristic lesion pattern and obstetric history, a diagnosis of type V ACC was established. The patient was treated conservatively with topical calcipotriol and meticulous wound care, leading to progressive re‐epithelialization and residual atrophic scarring.ConclusionThis case illustrates the classic presentation of type V ACC associated with fetus papyraceus and supports the vascular disruption hypothesis as the predominant pathogenic mechanism. Awareness of this rare entity facilitates early diagnosis, appropriate conservative management, and accurate counseling of parents regarding the excellent prognosis and low recurrence risk.

BackgroundCamptodactyly–arthropathy–coxa vara–pericarditis (CACP) syndrome is a rare autosomal recessive disorder caused by PRG4 mutations that impair lubricin production. Resulting noninflammatory hyperplasia produces congenital or early‐onset camptodactyly and noninflammatory arthropathy, affecting large joints. Because clinical features overlap with trigger finger and juvenile idiopathic arthritis (JIA), misdiagnosis is common.Case PresentationWe describe the second genetically confirmed Brazilian case of CACP, involving two siblings. Both showed congenital trigger fingers (later reclassified as camptodactyly) and developed painless, cold swelling of large joints, initially labeled JIA. Laboratory tests showed normal inflammatory markers, and synovial fluid revealed low white cell counts. Imaging demonstrated joint effusion and synovial debris without inflammatory signs. Whole‐genome sequencing identified a homozygous c.3756dup mutation in the PRG4 gene, introducing a premature stop codon and truncating lubricin.ConclusionThis report highlights the importance of recognizing CACP syndrome by identifying distinctive clinical, laboratory, and imaging characteristics, notably congenital camptodactyly and noninflammatory joint swelling, to prevent misdiagnosis and guide supportive management.

IntroductionAcute mastoiditis, a complication of acute otitis media (AOM), remains a concern in children despite vaccines and antibiotics. Serious complications like cerebral venous sinus thrombosis (CVST) can be life‐threatening.Case PresentationA 4‐year‐old girl with fever, vomiting, and ear pain worsened despite amoxicillin treatment, developing headache, neck stiffness, and drowsiness. An ENT examination showed thickened tympanic membranes. Neurological symptoms, including headache, drowsiness, and neck stiffness, prompted lumbar puncture and initiation of ceftriaxone, with elevated CRP and leukocytosis supporting the clinical suspicion. Imaging confirmed otomastoiditis with epidural extension and CVST. MRI confirmed intracranial complications, prompting anticoagulation. She underwent mastoidectomy and tympanostomy tube placement, recovering well.ConclusionEarly imaging and multidisciplinary management are essential to prevent neurologic complications in children with mastoiditis.

PurposeTo present a case of type II oculocutaneous albinism (OCA2) diagnosed in infancy following the finding of nystagmus, and to review the diagnostic process and the management of this disorder.ObservationA 4‐month‐old female presented with subtle, roving eyes that were initially attributed to normal development. A subsequent evaluation by a pediatric ophthalmologist, prompted by a high index of suspicion, confirmed the findings of nystagmus, mild foveal hypoplasia, and astigmatism. Genetic testing confirmed the presence of pathological variants of the OCA2 gene, leading to a diagnosis of oculocutaneous albinism.Conclusion and ImportanceThis case highlights the importance of a meticulous ophthalmologic examination and a high index of suspicion in pediatric care. The early finding of nystagmus can be the key to a timely diagnosis of OCA2. This allows for early intervention to optimize visual development and allows for multidisciplinary management and genetic counseling for the family. This case underscores the need for ongoing education in enhancing the early detection of OCA.

Infants with severe hyponatremia (Na < 120) and an abdominal mass require an astute clinical evaluation and often represent a medical emergency. We report a case of a 2‐month‐old White female, born full term, presenting with a two‐day history of decreased oral intake and urinary output, who was found to have severe hyponatremia with notable abdominal distention. Abdominal imaging revealed the presence of a pelvic mass causing obstructive uropathy. Further imaging and urogenital examination revealed a hydrometrocolpos. This rare entity required urgent surgical intervention and standard supportive care in the PICU. She had a subsequent significant improvement in symptoms and prevention of further deleterious complications.

Lithium button battery ingestion represents a growing pediatric emergency, potentially associated with severe local and systemic complications. This article reports three cases of lithium battery ingestion with varying degrees of esophageal and tracheal involvement, treated at a pediatric surgery referral hospital in Brazil between 2023 and 2024. In addition, a review of the literature addressing pathophysiology, diagnostic and therapeutic management, and predictors of severity is presented. The reported cases illustrate the wide spectrum of injury severity and the impact of delays in medical care related to structural limitations commonly encountered in low‐ and middle‐income countries. An adaptive strategy for the management of severe airway injury in the absence of extracorporeal membrane oxygenation (ECMO) support is also described.

BackgroundFibrous hamartoma of infancy (FHI) is a rare benign tumor typically found in the axilla or trunk. Distal extremity involvement is exceptional. We present the first documented case of FHI of the hand in the Philippine literature, highlighting the conflict between oncologic clearance and functional preservation.Case PresentationA 7‐month‐old male presented with an enlarging hypothenar mass. Initial ultrasonography revealed a heterogenous mass with intralesional cystic spaces, leading to a misdiagnosis of hemangioma despite the absence of significant flow on Doppler interrogation. Propranolol treatment failed. MRI revealed a poorly encapsulated mass encasing muscles, raising suspicion for malignancy. Intraoperatively, the tumor appeared as matted tissue with nondelineated borders, encroaching on neurovascular structures. To preserve hand function, a subtotal excision was performed rather than radical en bloc removal. Histopathology confirmed the triphasic components diagnostic of FHI.ConclusionLocal recurrence was noted 6 months postoperatively before the patient was lost to follow‐up. This case underscores the diagnostic challenge of FHI in the hand due to vascular mimicry. Furthermore, the tumor’s infiltrative nature in complex anatomy forces a difficult trade‐off: Radical excision offers cure but risks functional devastation, whereas functional preservation carries a high risk of recurrence.

Proprotein convertase subtilisin/kexin type 1 (PCSK1) is an enzyme involved in processing prohormones into active peptides. PCSK1 deficiency is a rare genetic condition in which the homozygous presentation has been documented to cause diarrhea during infancy, as well as childhood obesity, high levels of proinsulin, and diverse endocrine abnormalities. An eleven-year-old male was evaluated in the pediatric cardiology clinic for hypertriglyceridemia and rapid weight gain. He had recently been diagnosed with heterozygous PCSK1 deficiency, defined as c.661A > G, which is predicted to result in the amino acid substitution p.Asn221Asp. The patient reported regular hyperphagia to the point of nausea, with a diet of processed and sugary foods. Past medical history included obstructive sleep apnea and migraines. Physical examination was unremarkable aside from severe obesity (BMI 39.7 kg/m2) and elevated blood pressure. His fasting lipid panel showed elevated triglycerides (330 mg/dL), low HDL (38 mg/dL), normal LDL (71 mg/dL), elevated total cholesterol (175 mg/dL), and normal HbA1c (5.0%). The patient was counseled on lifestyle modifications with the weight management clinic and began a structured weight loss program along with discussions of possible GLP-1 agonist initiation. Follow-up lipid monitoring was planned in 3 months after the cardiology clinic visit. This case of a heterozygous PCSK1 variant may demonstrate an association between this variant and the patient's clinical presentation, possibly expanding the known clinical spectrum of the disorder beyond the previously reported presentations in homozygous cases. Our case may show how heterozygous presentations with this variant of PCSK1 deficiency demonstrate a different presentation from the homozygous phenotype in younger patients. This patient shows that PCSK1 abnormalities could have an association with individuals who have hyperphagia and significant obesity, but normal HbA1c and LDL levels. Additional studies could be considered to evaluate prevalence in the population, long-term outcomes, and targeted therapies.

Kawasaki disease is a systemic inflammatory disorder that is frequently encountered in routine pediatric clinical practice. Conversely, trisomy 18 is a chromosomal disorder with a historically poor prognosis. However, recent advances in medical care have improved its survival, with a reported 1-year survival rate reaching 29%. Despite this improvement, studies describing the clinical course of individuals with trisomy 18 beyond the first year of life remain scarce. Moreover, to our knowledge, cases of Kawasaki disease with trisomy 18 have not been reported. We report a case of a 3-year-11-month-old girl with trisomy 18 who presented with persistent fever and rash and, subsequently, fulfilled five of the six principal diagnostic criteria for Kawasaki disease. Because intravenous immunoglobulin resistance was predicted based on the Kobayashi score, initial treatment consisted of intravenous immunoglobulin (2 g/kg), aspirin, and oral cyclosporine concurrent with current Japanese guidelines. Defervescence was achieved without complications, and no adverse events were observed during treatment. No coronary artery abnormalities were observed during the acute phase or at 1-, 3-, and 6-month follow-up evaluations. We present a case of trisomy 18 treated according to Japanese guidelines for Kawasaki disease. Treatment regimen, which included cyclosporine, was safely administered, and the patient experienced a favorable clinical course. To improve the life expectancy of this patient group, it is crucial to accumulate comprehensive natural history, including the efficacy of standard treatments for various pediatric conditions. This will enable timely and appropriate therapeutic interventions.