Urachal Rhabdomyosarcoma in Children: A Rare Malignancy with Review of Literature.

Urachus is a tubular remnant connecting the bladder's apex to the umbilicus, where urine initially drains in the fetus during embryonic development. We report a rare case of a 7-year-old boy presenting with an asymptomatic lower abdominal lump. Physical examination revealed a nontender hypogastric mass. Contrast-enhanced computed tomography scan was suggestive of a large abdominopelvic mass abutting the anterior abdominal wall. Ultrasound-guided percutaneous biopsy followed by a histological analysis with immunohistochemistry showed embryonal rhabdomyosarcoma (RMS). Further metastatic workup ruled out distant metastasis. The patient received neoadjuvant chemotherapy followed by surgical excision. The tumor was primitively related to the urachus and involved the serosal surface of the bladder dome without detrusor infiltration, suggestive of the urachal RMS. Total macroscopic resection of the urachal mass with partial cystectomy was performed. The child underwent adjuvant chemoradiotherapy in the postoperative period without any recurrence at 1-year follow-up.