Misdiagnosis on CT of a Rare Tumor

Figure 1. Contrast-enhanced coronal CT showing a cystic mass with peripheral calcification superior to the bladder dome.

Figure 2. Contrast-enhanced axial CT showing cross-fused renal ectopia.

Figure 3. Sagittal CT showing the relation of the mass and the bladder.

Upon visualizing the area during laparoscopy, it became clear that the lesion was not ovarian in nature; it was described as a white mass adherent to the bladder and communicating with the anterior abdominal wall with the presence of mucinous secretions.

Figure 4. Cystoscopy findings of a mass in the bladder dome, which was subsequently biopsied.

It was concluded that peritonectomy would not be suitable and for chemotherapy to continue with a regime of gemcitabine and cisplatin.

This case highlights the need for awareness of this rare type of malignancy. Overall, the timeframe between the first and second CT scans was six months, representing a significant delay in definitive treatment.

Anatomically, the urachus extends from the dome of the bladder to the umbilicus and is typically comprised of a fibromuscular cord remnant caused by the involution of the cranial portion of the vesicourethral canal.1

Radiological evaluation mainly focuses on CT findings to both identify the mass and stage the disease.

In terms of the egg-shell pattern of calcification within the mass, a study of 25 cases of urachal carcinoma showed calcification was present in 72% of tumors and was more common peripherally.3

It is reasonable to assume that the consideration of an aggressive urological malignancy in the early stages would have prompted an urgent urology referral and earlier intervention.