Incidentally discovered urachal cancer in a patient with necrotising fasciitis of the abdominal wall.

To cite: Shaw N, Marchalik D, Stamatakis L. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2015-213226 DESCRIPTION Urachal cancers are rare, accounting for <0.7% of all bladder cancers, and the majority (>90%) are adenocarcinomas. We describe a case of a patient with poorly controlled diabetes presenting with a 4-day history of an expanding, painful abdominal rash. CT scan performed on admission demonstrated an umbilical hernia (figure 1A) consisting primarily of fat and a 7×5×7 cm mass (figure 1C), radiographically consistent with a tumour. Given a clinical picture consistent with necrotising fasciitis (tachycardia, marked leucocytosis, and expanding erythaema and crepitus of the abdominal wall), the patient underwent extensive surgical debridement. Intraoperative cultures confirmed methicillinresistant Staphylococcus aureus. Pathological evaluation revealed moderately differentiated papillary carcinoma with urothelial and squamous differentiation most likely of urachal origin (figure 1B). Cytopathological staining was positive for CD7, CD5/6, P63 and GATA 1, and was negative for CDX2 and uroplakin; CK20 and 34BE12 stains were not performed. The patient’s hospital course was complicated by cardiac arrest with cardiopulmonary resuscitation and long-term ventilation. Owing to the severity of her condition, cystoscopic evaluation was not performed. The patient underwent multiple subsequent debridements and the prognosis remained poor at the time of writing. Urachal cysts have been reported as the source for abdominal wall infections, but urachal cancer as a nidus has not been described. The role of the patient’s tumour in the development of the lifethreatening infection remains unclear.