Chiara Grassani1, Michele Potenzoni1, Anna Maria Pieri1, Carmelo Sergio Destro Pastizzaro1, Daniel Martens1, Nicoletta Uliano1, Roberto Arnaudi1, Luigi Benecchi2, Antonio Savino1, Domenico Corradi3, Andrea Prati1
  • 1 Ospedale di Vaio (Fidenza)
  • 2 Istituti Ospitalieri di Cremona (Cremona)
  • 3 Istituto di Anatomia Patologica Ospedale di Parma (Parma)


Mesenchymal/fibroblastic spindle cell proliferation constitue an exedingly broad and various category of disorder, ranging from indolent to highly aggressive neoplasm
well differentiated papillary mesothelioma[1].These group of neoplasm occurring in urinary bladder are rare, the differential diagnosis is often challenging and the cystoscopic report is not always sharply clear.
The inflammatory myofibroblastic tumour (IMT) is a locally aggressive neoplasm with a variable degree of aggressiveness, extremely rare, and the differential diagnosis with a true sarcoma is of paramount importance, because of the following surgical indication and and patient followup, being the malignant evolution in IMT highly rare[2].
In this report, we have described the case of an adult woman affected by a classic IMT, which recurred and turned into malignant inflammatory fibrosarcoma during a higly short term with patient exitus in 6 months from the first diagnosis.

Methods and results

A 74 years old woman underwent a TUR of a small bladder lesion underlined by apparently normal mucosa. The relative microscopic examination revealed a quite homogeneus myoibroblastic proliferation, constituted of bland cellularity with no clar-cut evidence of atypia. On immunohistochemistry the spindle cells were positive for vimentin, smooth muscle actin, ALK-1, and focally CK, being in keeping with IMT[2].
A 2 months later US scan showed a voluminous, solid, bladder mass highly vascularized, of 4,4 cm diameter. The surgical specimen of the following radical cystectomy displayed an 8 cm lesion infiltrating the bladder wall and the perivescical adipose tissue. The histologic diagnosis was of infiammatory fybrosarcoma³. After 2 months, CT scan revealed multiple bilateral lang nodularites involving right anonimous trunk, with right succlavial thrombus and multple iliac lynfoadenopaty. The patient died 3 months later the last operation.


In 1939, Dr. Harold Brunn described in two child a spindle cell proliferation affecting their lungs, characterized by inflammatory infiltrate, small areas of fibrosis and systemic symptoms [4]. Very likely, this was the earliest report of IMT. The first case involving the urinary bladder was reported in 1980 by Roth, who described such a lesion in a 32 years old woman and labelled it as a reactive disorder, in view of the absence of malignant elements and its benign course [5]. Four years later, Proppe et al. reported eight cases of very similar spindle cells developed after genitourinary (GU) surgery, they were named “postoperative spindle cells nodule” [6]. and considered benign reactive lesions reseambling a sarcoma. From then on, this myofibroblastic proliferation has had a number of designation i.e. inflammatory pseudotumor, inflammatory pseudosarcomatuous fibromyxoid tumor, plsma cell granuloma, plasma cell pseudotumor, xantomatous pseudotumor [3-7]. The modern term IMT was first proposed by Pettinato et al in 1990 in their report of 20 lung cases[8].
The infiammatory myofibroblastic tumour of the urinary bladder is an uncommon entity affecting more frequently male than female(2:1 to 3:1 ratio) in young age, though it has been reported in a wider age range[2-3].
Its pathogenesis is still unknown; theories have been suggested ranging from infective sequelae, e.g. Viral (HBV-HHV8), or bacterial (Pseudomonas), to autoimmune processes[2]. Its clinical evolution is variable, generally favorable, until spontaneous regression. Painless haematuria is the most common symptom, while more rarely patients complain of dysuria, pelvic pain, infections. Sometimes, systemic signs such as fever and weight loss have been reported [7-10]. Although the large majority oh authors have described and labelled IMT as a benign lesion, some of them have questioned this trend, especially for tumors affecting the GU tract, and considered this myofibroblastic proliferation as part of a spectrum ranging from benign/reactive lesions to frankly malignant sarcomas[2-3]. In fact modern genetic investigations have recently driven to the concept that IMTs should be interpreted as true neoplasm. Especially when localized in the GU tract, these lesions can share pathological features with conventional IMT but they may become much more aggressive and it has been proposed to define them as low grade sarcoma, being part of a spectrum ranging from pseudosarcomatous lesion to frankly inflammatory fibrosarcomas [9].The malignant potentiality is clearly supported by the clinical-pathological evolution of the patient we presented, suggesting that IMT should be considered neoplasm of uncertain malignant potential demanding very close clinical follow-up and appropriate radical management when a more aggressive progression becomes evident.


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9 Coffin Cm, Dehner LP, Meis Kindblom JM. Inflammatory myofibroblastic tumor, inflammatory fibrosarcoma, and related lesion: an histological rewiew with differentil diagnostic consideration. Semin Diagn Pathol. 1998;15:102-10
10 Coffin CM, Watterson J, Pries