Urinary bladder cyst: This is a common benign condition that can present as a cystic lesion in the bladder. It is often asymptomatic and found incidentally on imaging studies.

Bladder diverticulum: A bladder diverticulum is an outpouching of the bladder wall that can appear as a cystic lesion. It is usually a congenital condition but can also be acquired.
Bladder tumor (papillary urothelial carcinoma): Although less common than benign conditions, a bladder tumor can sometimes present with cystic components. The presence of a solid component or irregular borders may suggest this diagnosis.
Intravesical hematoma: Blood clot in the bladder can sometimes appear as a cystic lesion, especially if it is organized and has a fluid-debris level.

Urachal cyst or urachal carcinoma: The urachus is a remnant of the allantois that connects the bladder to the umbilicus. A cyst or carcinoma in this area can extend into the bladder and appear as a cystic lesion. Missing a urachal carcinoma could have significant consequences due to its potential for malignancy.
Bladder metastasis: Metastatic disease to the bladder from other primary sites (e.g., stomach, breast, or melanoma) can occasionally present as a cystic lesion. Although rare, missing a diagnosis of metastasis could have serious implications for patient management and prognosis.

Bladder endometriosis: Endometrial tissue can rarely implant in the bladder wall, leading to cystic lesions, especially in women with a history of endometriosis.
Bladder malacoplakia: A rare inflammatory condition that can cause cystic or mass-like lesions in the bladder, often associated with chronic infection.
Bladder parasitic infections (e.g., echinococcosis): In endemic areas, parasitic infections can cause cystic lesions in the bladder, although this is exceedingly rare.