Rectal polyps are relatively common in children and most often present as painless rectal bleeding after defecation. By contrast, rectal prolapse caused by an underlying rectal polyp is uncommon, especially in pediatric patients. Because intermittent prolapse may have resolved by the time of clinical examination, the diagnosis can be difficult to establish. A previously healthy 1-year-old boy was referred to the pediatric surgery outpatient clinic because of a 6-month history of intermittent protrusion of a mass through the anus after defecation. The episodes initially occurred approximately three times per day but gradually increased to six times per day. Physical examination showed no definite perianal abnormality; however, a photograph provided by the patient’s mother showed a protruding anorectal mass, raising suspicion for rectal prolapse associated with a polyp. Colonoscopy revealed a large pedunculated rectal polyp, measuring approximately 47×34×25 mm, with a short stalk located approximately 15 cm proximal to the anal verge. The patient underwent transanal excision under general anesthesia. Histopathological examination confirmed a Peutz-Jeghers-type hamartomatous polyp. The postoperative course was uneventful, and no recurrence was observed during 3 years of follow-up. Rectal polyps should be considered in the differential diagnosis of recurrent rectal prolapse in infants and young children. Caregiver-provided photographs can help establish the diagnosis when the lesion is not visible during examination. In selected pediatric patients with large rectal hamartomatous polyps presenting with recurrent prolapse, transanal excision may provide safe and effective treatment.

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare and highly aggressive malignant mesenchymal neoplasm that occurs mainly in school-aged children. Preoperative diagnosis is challenging because clinical symptoms are nonspecific and imaging findings can vary substantially. Despite these diagnostic difficulties, survival has improved markedly with modern multimodal treatment. A previously healthy 10-year-old girl presented with acute right upper quadrant abdominal pain. Laboratory findings were largely unremarkable, and the alpha-fetoprotein level was within the normal range. Contrast-enhanced abdominal computed tomography and magnetic resonance imaging showed a large heterogeneous cystic mass in the right hepatic lobe, with internal hemorrhage, hemorrhage-fluid levels, and enhancing solid components. Right hepatectomy was performed, and complete tumor resection was achieved. Histopathological evaluation revealed a high-grade malignant mesenchymal tumor with pathological and immunohistochemical features consistent with UESL. The patient subsequently received adjuvant chemotherapy. At 21 months after surgery, she remained disease-free, with no radiological or clinical evidence of recurrence. This case highlights the diagnostic value of characteristic imaging findings and the therapeutic importance of complete resection followed by adjuvant chemotherapy. Early recognition and coordinated multidisciplinary management are essential for improving prognosis in children with this rare hepatic malignancy.