The urachus is an epithelial tubular structure located in the midline that spreads from the anterosuperior part of the bladder to the umbilicus, connecting the apex of the urinary bladder with the allantois in the fetus, and is involved in forming the umbilical structures. When the urachal tract is not completely obliterated during embryonic development, bladder diverticulum, urachal cyst, umbilical polyp, or patent urachus may result. Therefore, making a differential diagnosis prior to surgery is not easy. A 40-year-old woman presented to the outpatient clinic with abdominal pain in the suprapubic and infraumbilical region for 2 weeks and foul smelling purulent discharge from the umbilicus for 1week. There were no urinary symptoms, and she was afebrile. Physical examination revealed periumbilical tenderness and minimal guarding. An ultrasound scan revealed umbilical abscess. After undergoing preoperative examinations, the patient was posted for surgery. On exploration abscess was drained and a striated structure was present between the bladder and the umbilicus and it is found to be patent urachus. The urachus is resected and sent for pathological analysis which confirmed the same. Urachal pathology in adulthood is rare. Often its presentation as acute abdominal pain is nonspecific and, as such, may cause many diagnostic problems. Differential diagnosis should include acute appendicitis and other inflammatory disorders. The patient’s history and physical examination are crucial for the correct diagnosis. It is important to have a thorough understanding of the embryology, anatomy, presentation, and relevant investigations for these anomalies. Ultrasound can be helpful for diagnosing the pathology of urachal remnants.The urachus or median umbilical ligament is an epithelial tubular structure located in the middle line that spreads from the anterosuperior part of the bladder to the navel, connecting the apex of the urinary bladder with the allantois in the fetus, and is involved in forming the umbilical structures. It is the embryological remnant of the cloaca and the allantois. The lumen of the urachus usually becomes obliterated during embryonic development. Descent of the bladder toward the pelvis stretches the urachus, eventually leading to obliteration of its lumen. The median umbilical ligament is the resultant fibrous cord that runs from the umbilicus to the dome of the bladder. Congenital defects, however, may occur. Occasionally, this obliterative process is incomplete, leading to a persistent urachal remnant (UR). UR diseases are rare and typically present in early childhood with unspecific symptoms such as abdominal pain or urinary problems. When the urachal tract is not completely obliterated during embryonic development, bladder diverticulum, urachal cyst, umbilical polyp, or patent urachus may result. Therefore, making a differential diagnosis prior to surgery is not easy.Case reportA 40-year-old woman presented to the outpatient clinic with abdominal pain in the suprapubic and infraumbilical region for 2 weeks and foul smelling purulent discharge from the umbilicus for 1week. There were no urinary symptoms, and she was afebrile. There were no signs of general infection. Physical examination revealed periumbilical tenderness and minimal guarding. An ultrasound scan revealed umbilical abscess. After undergoing preoperative examinations, the patient was posted for surgery. On exploration abscess was drained and a striated structure was present between the bladder and the umbilicus and it is found to be patent urachus. The urachus is resected and sent for pathological analysis which confirmed the same.The urachus is a fibrous remnant of the cloaca and the allantois, which in adults, connects the dome (anterosuperior part) of the bladder with the anterior abdominal wall (navel). The allantois is a fingerlike projection from the yolk sac, which is contiguous with the ventral cloaca at one end and the umbilicus at the other. The cloaca, in the fetal life, is the cephalic extension of the urogenital sinus (a precursor of the fetal bladder) and the allantois. The ventral portion of the cloaca develops into the bladder after cloacal division by the urogenital septum. Between the 4 th and the 5 th months of gestational age, the bladder drops toward the pelvis, and the urachus prolongs and narrows until it turns into an epithelialized fibromuscular cord. It lies in the space of Retzius, extending between behind the transversalis fascia and anterior to the parietal peritoneum, and is bordered laterally by the obliterated umbilical arteries (medial umbilical ligaments) 1 . The size of the urachus can range between 3 cm and 10 cm in length and 8 mm and 10 mm in diameter. After birth it obliterates, forming the median umbilical ligament. However, a vestigial small lumen lined by a transitional epithelium is seen commonly in the fully developed infant. The transitional epithelium is surrounded by a submucosal connective tissue layer and a thick outer smooth muscle coat 2 . Occasionally, the urachus may merge with one or both of the obliterated umbilical arteries, and there may be a slight deviation to the right or left of the midline 3 .Urachal anomalies can be classified into congenital and acquired anomalies. Congenital anomalies consist of defects in the obliteration of the urachus. Urachal congenital anomalies are of four types: persistent urachus, which communicates the bladder with the umbilicus; urachal cyst, a part of the urachal canal without any patent connection with the bladder or the umbilicus; vesicourachal diverticulum, a structure that opens within the bladder; and urachal sinus, which is a form of a cyst communicating with the umbilicus. Acquired anomalies are infections and malignant degeneration.The most commonly observed and managed urachal anomalies in children are urachal cyst (54%), urachal sinus (30%), patent urachus, and vesicourachal diverticulum 4 . Remnants found in neonates <6 months old usually resolve spontaneously without the need for surgery 4 . Those found in older patients require management and should uniformly be resected, as chronic exposure to urinary stasis increases the risk for infection and inflammation, and are of utmost importance in adults, due to an increased risk of neoplastic differentiation 5 . Any of these congenital anomalies can become overinfected. The infection route can be lymphatic, hematogenous, or vesical. Clinical symptoms of an urachal infection are fever, abdominal pain in the lower region or around the middle line, urinary problems with or without infection, and, sometimes, a suprapubic palpable mass. There is no consensus on the management of URs. Spontaneous resolution without the need for further intervention has been reported 5 . It is unclear whether all URs or a subset of symptomatic URs should be resected.Clinical significance of incidentally diagnosed remnants of normal embryologic urachal development is unclear. Understanding the natural history of incidentally diagnosed URs and outcomes based on their current management may help guide future strategies and possibly avoid unnecessary operations with their inherent risks. With an increase in incidental diagnosis, nonoperative management has become more common. Ueno et al 2 reviewed the ultrasound reports of 3400 patients and found that 56 children had a UR. Of these, 44 patients, including 11 symptomatic and 33 asymptomatic cases, were followed up without surgical resection. In nine cases, URs disappeared during the follow-up period. Only one patient had recurrent symptoms, which were successfully treated with antibiotics and without surgical intervention.Galati et al 6 retrospectively reviewed 23 patients treated for a UR, and found that overall 50% and in children less than 6 months of age 80% of URs resolved nonoperatively. Lipskar et al 7 reviewed their experience in managing 15 children with URs who were referred to them for symptoms associated with the remnants. Eight patients underwent surgical excision, while seven were managed nonoperatively for a mean follow-up time of 26 months. These reports suggest that URs identified by ultrasound may be observed without surgical intervention.There is a paucity of literature describing postoperative complications after UR resection. McCollum et al 1 reported on excision of 26 URs with one postoperative wound infection and one bladder leak. Cilento et al 8 reported 45 UR excisions with three postoperative wound infections. Neither of these studies indicates the duration of their follow-up.Urachal anomalies are twice as common in men as those in women 3 , and are rarely observed in adulthood. Modes of presentation differ from those seen in children. Urachal cancer (51%) and urachal cyst (35%), which is usually infected, are the most frequent modalities diagnosed in adults 4 . Some patients with URs are asymptomatic, but still carry a high risk for infection or cancer.The persistence of the urachus was described and treated for the first time in 1550 by Bartholomaeus Cabrolius 2 , and later a few cases of infected URs in adulthood were reported in the literature 9 . Persistent urachus is a full defect in the obliteration. It is usually diagnosed during the neonatal period, because the urine can flow back from the bladder to the navel through the persistent urachus, or discovered in childhood, but a late onset in adulthood is always possible. In these cases, the clinical presentation is highly variable and makes diagnosis difficult. In one-third of the cases, this condition is associated with posterior urethral valves or urethral atresia. In other patients, the urachus can be asymptomatic.First, urachal anomalies are rarely observed clinically, with only eight of 40,000 cases being admitted to a surgical department 9 . Second, the urachus is located in a clinically silent area, extraperitoneally in the space of Retzius. As a consequence, possible symptoms and clinical signs of inflammation as well as of tumors are, in most cases, nonspecific or delayed, or even absent. Inflammation as well as the development of an abscess can remain clinically unrecognized for a long time, or it can be considered as acute surgical abdomen.Typical clinical manifestations of patent urachal pathologies are umbilical discharge, tenderness, erythema, or a mass within the umbilicus. Abdominal pain can be the only symptom of disease, as seen in our case. The presentation of acute abdominal pain with abdominal guarding is less common. In these cases, the differential diagnosis should include several inflammatory pathologies, mainly acute appendicitis, but also cystitis, inflammatory bowel disease, strangulated umbilical hernia, pelvic or intra-abdominal abscess, and Meckel's diverticulum 4 and 10 .Diagnosis of the persistent urachus, presenting in the perinatal period, can often be made based on a thorough history and physical examination. In less clear cases, an ultrasound study will be diagnostic. Rarely, a sinogram may be used. In patients with other signs or symptoms of an underlying UR, including umbilical polyps, pain, suprapubic mass, or infection, ultrasound scan is the study of choice and is a diagnostic technique in more than 90% of cases. Additional studies, including voiding cystourethrogram or cystoscopy, play very little roles in an otherwise asymptomatic patient 1 .Treatment of symptomatic URs remains surgical. For the uncomplicated patent urachus, usually a one-stage procedure will suffice. This consists of a transverse infraumbilical incision, extraperitoneal dissection of the urachal tract, and excision of the tract from the base of the umbilicus to the dome of the bladder with a small bladder cuff, followed by two-layer closures with absorbable sutures 1 .The differential diagnosis of an umbilical mass should include hematoma, abscess, umbilical hernia, urachal carcinoma, and tumors of the abdominal wall. Ultrasound can be helpful, as shown by our case. Differentiation between benign UR and urachal cancer may be difficult due to unclear contrast enhancement during computed tomography, even though the presence of calcifications is suggestive of malignancy 4 .In our case, there was no suspicion for malignancy due to the patients' age and a negative history suggestive of malignancy (hematuria). When urachal cancer cannot be excluded (hematuria and mass seen at the bladder dome on imaging), cystoscopy with biopsy and urine cytology should not be omitted. Cytology is positive in 38% of patients with urachal carcinoma and is correlated with an increased tumor grade. If urachal pathology appears with signs of infection, a two-stage treatment is recommended: initially, administration of antibiotics and resolution of inflammation, associated with the draining of the cyst or purulent collection, followed by surgical removal 4 . In benign urachal anomalies, complete excision, with or without the cuff of the bladder, is sufficient. It is not necessary to remove the umbilicus. The surgical treatment prevents the possibility of a malignant degeneration toward adenocarcinoma, sarcoma, or transitional cell carcinoma. In case of urachal cancer, partial or radical cystectomy should be considered. Partial cystectomy with en bloc resection of the urachus with cancer within the bladder dome provides similar oncologic outcomes to radical cystectomy 4 . Open partial cystectomy is performed with a midline incision below the umbilicus. The umbilicus with the urachus and bladder dome are resected with large margins (2 cm) of healthy tissue. Reports on laparoscopic partial cystectomy with urachus removal have been published 4 . It has been emphasized that the ports should be inserted 3–5 cm above and 2 cm to the left of the umbilicus, to allow proper access to the operating field. The approach should be dictated by the surgeon's preferences and experience to ensure the best possible oncologic results.Urachal pathology in adulthood is rare. Often its presentation as acute abdominal pain is nonspecific and, as such, may cause many diagnostic problems. Differential diagnosis should include acute appendicitis and other inflammatory disorders. The patient's history and physical examination are crucial for the correct diagnosis. It is important to have a thorough understanding of the embryology, anatomy, presentation, and relevant investigations for these anomalies. Ultrasound can be helpful for diagnosing the pathology of URs.