Imaging description

Inflammatory pseudotumors are rare benign masses of uncertain etiology composed of spindle cells mixed with variable amounts of extracellular collagen, lymphocytes, and plasma cells [1]. Inflammatory pseudotumor most commonly affects the lungs and orbits, but can occur virtually anywhere. The bladder is perhaps the commonest site of involvement in the abdomen and pelvis. Inflammatory pseudotumor forms a polypoid or infiltrative bladder mass, which may be ulcerated or extend into the perivesical fat (Figures 88.1–88.3) [1–4]. A wide variety of terms have been used to describe this condition, including inflammatory myofibroblastic tumor, plasma cell granuloma or pseudotumor, and pseudosarcomatous myofibroblastic proliferation. The term inflammatory myofibroblastic tumor has recently become increasingly common in pathological usage, based on electron microscopic and immunohistochemical findings [5,6].

Importance

Inflammatory pseudotumor of the bladder can mimic transitional cell carcinoma, both clinically and radiologically. Awareness of this entity and its inclusion in the differential diagnosis may prevent unnecessary radical surgery, since inflammatory pseudotumor of the bladder can usually be managed by conservative surgery such as transurethral resection or partial cystectomy [7].

Typical clinical scenario

Most cases of inflammatory pseudotumor of the bladder occur in childhood or early adulthood. Women are affected about twice as often as men [8]. Patients may be asymptomatic or have constitutional symptoms such as fever or weight loss. Local symptoms may include pain, hematuria, urinary frequency, or dysuria. While the condition can recur, the prognosis is usually good if the mass is completely resected [1].