www.elsevier.com/locate/jpedsurg

Inflammatory pseudotumor of the ureter

Luke Harpera, Jean-Luc Michela,*, Jean-Pierre Riviereb, Atta Alsawhic,Stephan De Napoli-Coccia

aDepartment of Pediatric Surgery, Felix Guyon Hospital, Saint-Denis, Reunion Island, 97400 FrancebDepartment of Pathology, Felix Guyon Hospital, Saint-Denis, Reunion Island, 97400 FrancecDepartment of Urology, Felix Guyon Hospital, Saint-Denis, Reunion Island, 97400 France

0022-3468/05/4003-0030$30.00/0 D 20

doi:10.1016/j.jpedsurg.2004.11.024

* Corresponding author. Service de

talier Departmental Felix Guyon, Bellep

France. Tel.: +33 262 262 90 54 91; fax

E-mail address: jl-michel@chd-fguy

Index words:Inflammatory

myofibroblastic

pseudotumor;

Ureter;

Immunohistochemistry;

Neoplasm

Abstract Inflammatory myofibroblastic pseudotumors are rare solid tumors found in most soft tissue

locations although mainly in the lung. Their etiology is uncertain, and they are generally considered

benign although some have a potential for recurrence and dissemination. Recent studies have

suggested, however, that some of these tumors are in fact neoplastic processes that harbor chromosomal

aberrations similar to those seen in certain lymphomas. The authors report a case of inflammatory

pseudotumor of the ureter in a child and discuss recent reports.

D 2005 Elsevier Inc. All rights reserved.

Inflammatory pseudotumors (IPTs) are rare solid

tumors originally described in the lung but have since

been reported in various other soft tissue locations such

as the spleen, heart, and mesentery [1,2]. They have a

characteristic histological appearance consisting of a

mixture of myofibroblastic and/or hystiocytic spindle

cells and a polymorphic inflammatory cell infiltrate [2].

Although considered benign, some of these tumors,

particularly in the abdomen, have the potential for a

more aggressive clinical course including multiple recur-

rences and, in rare cases, metastatic spreading [1]. They

occur mainly in children and young adults but can occur

at any age. Inflammatory pseudotumors have only rare-

ly been described in the urinary tract, we describe such

a case.

05 Elsevier Inc. All rights reserved.

Chirurgie Infantile, Centre Hospi-

iere, 97405 CEDEX, Saint-Denis,

: +33 262 262 90 54 98.

on.fr (J.-L. Michel).

1. Case report

A 13-year-old boy presented with pain in the left flank

that had begun 1 month earlier. Radiological studies

(including ultrasound and excretory urogram; Fig. 1)

showed moderate left hydronephrosis with a clear obstacle

of the distal portion of the ureter. At this moment, the

first hypothesis was that of an inflammatory process

surrounding a calculus. We performed a cystoureteroscopy

and saw a soft tissue obstacle of undetermined origin and

therefore introduced a double J stent in the left ureter. The

pathological analysis of a fragment of the obstacle

revealed unidentifiable necrotic and fibrous tissues.

After 6 weeks, the double J stent was removed. We

then observed a recurrence of the dilatation and obstacle

of the left ureter and a functional impairment of the left

kidney on the diuretic renal MAG 3 scintigraphy with an

obstructive renographic pattern and a decrease in relative

function (39% for the left kidney and 61% for the right

kidney). Both pelvic echography and computed tomogra-

phy scan results were normal apart from the ureteral

dilatation, confirming the absence of any pelvic anomaly.

Journal of Pediatric Surgery (2005) 40, 597–599

Fig. 1 Excretory urogram showing an obstacle of the distal

portion of the left ureter (arrow) with slight ureterohydronephrosis.

Fig. 3 Histological appearance of the tumor showing inflamma-

tory and myofibroblastic cells (H&E stain; original magnification,

�200).

L. Harper et al.598

All laboratory findings including those on renal function,

blood (hemogram), C-reactive protein level, and urine

(urinalysis) were normal.

We decided to perform a surgical exploration, which

showed a 1.5 � 1 cm olive-shaped obstructive lesion of the

Fig. 2 External view of the olive-shaped pseudotumor. B

indicates bladder; K, kidney; IPT, inflammatory pseudotumor.

ureteral wall, 3 cm from the ureterovesical junction (Fig. 2).

We performed a resection of the lesion and reimplanted the

left ureter using the Politano-Leadbetter procedure.

Pathological analysis revealed a reactional inflammatory

myofibroblastic pseudotumor of the ureter (Fig. 3),

characterized by a positive reaction to smooth muscle ac-

tin and negative reactions to anticytokeratin KL1, S100

protein, desmin, and ALK 1, as shown by immunohisto-

chemistry. At 1 year of follow-up, the obstacle has dis-

appeared and the boy was well.

2. Discussion

Although most commonly found in the lungs, IPTs

have been reported to involve the brain, heart, pericardi-

um, trachea, lymph nodes, pelvis, and gastrointestinal tract

[2,3]. Urinary localizations are rare and include mainly the

bladder, kidney, and renal pelvis [4].

The etiology of these tumors is still unclear; some

authors suggest an exaggerated inflammatory response to

trauma or infection [5], whereas others propose a role for

viruses including the Epstein-Barr virus and human

Herpesvirus 8 [6,7]. Inflammatory pseudotumors have

classically been regarded as distinct nonneoplastic self-

limiting lesions containing myofibroblastic and inflamma-

tory cells that arise in most soft tissues. However, more

recently, some of these lesions—those that have the

potential for a more aggressive clinical course—have been

shown to be clonal tumors that in some cases harbor

chromosomal translocations involving the ALK kinase

gene [8,9], and malignant transformation after successive

recurrences has been reported with an overall mortality rate

of up to 7% [10].

Although surgery remains to be the treatment of choice,

in certain localizations, when tumor size implies extensive

and potentially damaging surgery, alternative treatments

such as steroid therapy and radiation have been reported to

Inflammatory pseudotumor of the ureter 599

be successful in achieving tumor regression. However, even

after radical treatment, recurrences have been reported.

In our case, pathological analysis showed the tumor to

be ALK kinase negative; however, when in the presence

of ALK-positive strains, follow-up of these tumors should

be closer.

Inflammatory pseudotumors represent a heterogeneous

group of lesions with a wide spectrum of clinical behaviors.

Understanding the cause of these lesions and the character-

istics and biologic potential of each subset will enable

pathologists to inform clinicians about their expected

clinical behaviors. The potential malignancy of these lesions

warrants both aggressive surgical management and a close

follow-up of these patients.

References

[1] Coffin CM, Dehner LP, Meis-Kindblom JM. Inflammatory myoblastic

tumor, inflammatory fibrosarcoma, and related lesions: an historical

review with differential diagnostic considerations. Semin Diagn

Pathol 1998;15:102-10.

[2] Coffin CM, Watterson J, Priest JR, et al. Extrapulmonary inflamma-

tory myofibroblastic tumor (inflammatory pseudotumor); a clinico-

pathologic and immunohistochemical study of 84 cases. Am J Surg

Pathol 1995;18:859 -72.

[3] Sanders BM, West KW, Gingalewski C, et al. Inflammatory

pseudotumor of the alimentary tract: clinical and surgical experience.

J Pediatr Surg 2001;36:169 -73.

[4] Poon KS, Moreira O, Jones EC, et al. Inflammatory pseudotumor of

the urinary bladder: a report of five cases and review of the literature.

Can J Urol 2001;8:1409 -15.

[5] Freud E, Bilik R, Yaniv I, et al. Inflammatory pseudotumor in

childhood. A diagnostic and therapeutic dilemma. Arch Surg 1991;

126:653-5.

[6] Arber DA, Kamel OW, van de Rijn M, et al. Frequent presence of the

Epstein-Barr virus in inflammatory pseudotumor. Hum Pathol 1995;

26:1093-8.

[7] Gomez-Roman JJ, Sanchez-Velasco P, Ocejo-Vinyals G, et al. Human

herpes-8 genes are expressed in pulmonary inflammatory myofibro-

blastic tumor (inflammatory pseudotumor). Am J Surg Pathol 2001;

25:624-9.

[8] Su LD, Atayde-Perez A, Sheldon S, et al. Inflammatory myofibro-

blastic tumor: cytogenetic evidence supporting clonal origin. Mod

Pathol 1998;11:364-8.

[9] Lawrence B, Perez-Atayde A, Hibbard MK, et al. TPM3-ALK and

TPM4-ALK oncogenes in inflammatory myofibroblastic tumors. Am

J Pathol 2000;157:341 -5.

[10] Dao AH, Hodges KB. Inflammatory pseudotumor of the pelvis:

case report with review of recent developments. Am Surg 1998;64:

1188-91.