Inflammatory Pseudotumour of the BladderA Case Report

Dragomir P. Zubac,1 Stig Malmfred2 and Benni Nerstrøm3

From the 1Department of Surgery, Urology Section, Haukeland Hospital, Bergen, Norway, 2Department of Surgery, GællivareHospital, Sweden and 3Department of Surgery, Urology Section, Arhus, Denmark

(Submitted December 10, 1998. Accepted for publication August 25, 1999)

Scand J Urol Nephrol 34: 72–74, 2000

Dragomir P. Zubac, MD, Department of Surgery, Urology Section, Haukeland Hospital, PO Box 1, NO-5021 Bergen,Norway. Tel:�47 55 97 50 00. Fax:�47 55 97 27 93. E-mail: zubac@anote.com

Inflammatory pseudotumour (IPT) is a rare prolifera-tive lesion that can occur in both children and adults. Itmay be locally aggressive and can be localized to thelungs (1–3), liver (4, 5) or genitourinary tract (6–8).Clinically and radiologically, IPT simulates a malig-nant tumour and histopathologically can even bemistaken for a neoplastic lesion. The recommendedmanagement of most cases is local excision of the IPTand a close follow-up.

We describe an IPT of the bladder in a 45-year-oldman, who presented with sudden onset of gross,painless haematuria and a large polypoid and ulceratedbladder mass found at endoscopy. Initial pathologicalanalysis was interpreted as interstitial cystitis with aHunner’s ulcer, but subsequent reviews were consistentwith a benign process resembling IPT of the bladder.After incomplete transurethral resection, a partialcystectomy was carried out. No recurrences wereseen at follow-up examinations 12 months aftersurgery.

CASE REPORT

A forty-five-year-old man was admitted on December4, 1996 with gross haematuria and burning at micturi-tion of one week’s duration. Urine cultures werenegative and there had been no known exposure totoxic agents and trauma. The patient was a non-smoker.

Physical findings on admission were essentiallyunremarkable. Haemoglobin was 15.1 Gm/100 ml,coagulation parameters were within normal limits andurinalysis showed haematuria and no pyuria.

Cystoscopy showed a large 4� 3� 2 cm polypoidand ulcerated mass located on the left posterior lateralwall of the bladder. Intravenous pyelography showed a

large 4–5 cm irregular left-sided bladder lesion.Computed axial tomography of the abdomen revealeda mass in the bladder and no enlarged regional lymphnodes (Fig. 1). A laparoscopy was done and foundnormal. An initial biopsy was considered to representinterstitial cystitis with Hunner’s ulcer. An additionalcystoscopy and repeated biopsy of both tumours andthe macroscopically normal part of the bladder werecarried out two weeks later. Small biopsy specimens ofthe lesion were again interpreted as interstitial cystitisbut biopsy specimens of the other parts of the bladderdid not show signs of interstitial cystitis.

On January 15 an intended radical transurethralresection of the lesion was performed. Bimanualbladder palpation revealed a mass in the left part ofthe bladder and histopathologic examination demon-strated an IPT, which was not radically removed.Therefore a segmental bladder resection including leftureteral orifice and a subsequent ureteroneocystostomywas undertaken. The patient has been controlledcystoscopically at 3-month intervals for more thanone year and has had no recurrence of the tumour.

HISTOPATHOLOGICAL FINDINGS

Initial small biopsy specimens showed a deep ulceraccompanied by inflammatory cell infiltration, super-ficial granulocytes and in the deep portions of thelesion between the muscle fibres lymphocytes, eosino-philic granulocytes as well as mast cells. In onespecimen the predominant fibroblastic nature of thelesion was revealed. No signs of malignancy werefound.

Light microscopy of the transurethal resectionspecimens showed intermingling bundles of mainly

2000 Scandinavian University Press.ISSN 0036–5599 Scand J Urol Nephrol 34

CASE REPORT

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immature spindle and fibroblast-like cells as well asmany inflammatory cells. Macrophages, granulocytesand even mast cells were also seen.

Muscle fibres in the bladder wall were mostlydestoyed by the IPT and only scattered isles of intactmuscle cells were found in the transurethral specimens.There were no signs of increased mitosis frequency,atypical mitosis or cell polymorphism (Fig. 2). Focalareas of calcified tissue were noted.

Immunohistochemistry showed a destruction ofbladder muscle fibres by proliferation of deviatingimmunophenotypes of muscle cells and mesenchymalfibroblasts–myofibroblasts. CD68-positive histiocyteswere seen.

The partial cystectomy specimen showed full thick-ness involvement of the bladder wall and focalextensions of the fibrous tissue with predominant

collagen fibres and no cell proliferation into theperivesical fat or to the margins of the specimen.

COMMENT

Inflammatory pseudotumour of the bladder is anunusual benign lesion, which if the biopsies are smalland superficial can be mistaken for an interstitialcystitis and Hunner’s ulcer. Clinically and histopatho-logically, the most important differential diagnosis isleiomyosarcoma of the bladder (9–12).

Our patient presented with painless haematuria, andboth endoscopically and radiologically, the lesionappeared to be malignant. Repeated transurethralbiopsy of the lesion was interpreted as interstitialcystitis with Hunner’s ulcer.

The diagnosis of interstitial cystitis is based

Fig. 1. A mass in the bladderand no enlarged regionallymph nodes in a 45-year-oldpatient.

Fig. 2. Proliferation ofspindle cells with anassociated inflammatory cellinfiltrate. H&E �200.

Scand J Urol Nephrol 34

Pseudotumour of the bladder 73

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primarily on clinical and cystoscopic criteria. Theclassic clinical description is that of an elderly femalewith ulceration and marked submucosal oedema ofthe bladder, resulting in prominent abdominal pain.Most authors (13) agree that histologic abnormalitiesare usually found in all areas of the bladder thatcontain endoscopic evidence of disease, but meticu-lous studies (14) indicate that careful histologicexamination of the biopsy specimen from an areawithout endoscopically evident lesion will still showsmall microscopic changes. Our patient did not havethe clinical or endoscopic signs associated withHunner’s cystitis. Histologically, it was remarkablethat the biopsy specimens of the otherwise endosco-pically normal parts of the bladder did not show anysign of interstitial cystitis. A transurethral resectionwas therefore performed and IPT lesion in thesespecimens was supported. As the lesion was notradically excised, a partial cystectomy was under-taken.

IPT is an unusual, benign, locally aggressive urinarybladder lesion that may easily be mistaken for aninterstitial cystitis, or even inflammatory fibrosarcoma,rhabdomyosarcoma, leiomyosarcoma or sarcomatoidtransitional cell carcinoma, as evidenced by the fewcases in the literature. Accurate identification of IPT isclinically important in avoiding unnecessary radicaltreatments. Optimal management may be transurethralresection or segmental cystectomy, closely followed-up with cystoscopy and biopsy.

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12. Ro JY, Ayala AG, Ordonez NG, Swanson DA, BabaianRJ. Pseudosarcomatous lesions of the urinary bladder.Am J Clin Pathol 1986; 86: 583–90.

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patients with interstitial cystitis. Interstitial Cystitis.New York: Springer-Verlag, 1990: 83–90.

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