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inflammatory myofibroblastic tumour ( imft ) more commonly known as inflammatory pseudotumour is a relatively rare tumour with variable malignant potential .
typically seen in children and young adults it can occur anywhere in the body but is commonly described in the lungs , mediastinum and orbits .
we report a case of multifocal intraabdominal imft involving the omentum and mesentery presenting as multiple peritoneal masses similar to peritoneal carcinomatosis .
omental imft itself is a relatively rare form of abdominal imft ; less than 15 cases have been reported in the world literature .
omental imft presenting as multiple masses is extremely uncommon and to the best of our knowledge , a similar case has not been reported to date .
a 15-year - old adolescent girl was referred to our hospital with abdominal pain , intermittent fever and loss of weight for the past 3 months .
laboratory investigations showed reduced haemoglobin ( 9.3 g / dl ) ; other investigations ( total leukocyte count , differential count , eosinophil sedimentation rate ( esr ) , serum proteins ) were within normal limits .
ultrasound ( us ) of the abdomen showed a solid hypoechoic mass in the pelvis along the left superior aspect of the uterus with intralesional vascularity on colour doppler ( fig .
multiple lesions with similar features but of varying sizes were also seen on the parietal peritoneum with mild free fluid in the pelvic cavity ( fig .
figure 1us images show heterogeneous hypoechoic lesions in the pelvis ( a ) and on the parietal peritoneum ( c ) .
us images show heterogeneous hypoechoic lesions in the pelvis ( a ) and on the parietal peritoneum ( c ) .
following us , contrast - enhanced computed tomography ( ct ) was done to characterize and assess the extent of the mass .
it showed a large ( 7.26.3  cm ) , lobulated , well - marginated , hypervascular mass in the pelvis displacing the pelvic bowel loops with minimal ascites ( fig .
in addition , multiple peritoneal - based lesions with similar characteristics but of varying sizes were also noted ( fig .
d ) . radiologically the lesions mimicked those of carcinomatosis . a differential diagnosis of sarcoma , gastrointestinal stromal tumour ( gist ) , leiomyoma , lymphoma , inflammatory pseudotumour and castleman s disease was made .
us - guided fine needle aspiration cytology revealed scattered spindle cells and occasional multinucleated giant cells with no evidence of malignancy .
intraoperatively , a large lobulated vascular mass was seen arising from the greater omentum adherent to the sigmoid colon which was excised completely .
figure 2contrast - enhanced ct images show a lobulated hypervascular lesion in the pelvis with free fluid ( a ) .
contrast - enhanced ct images show a lobulated hypervascular lesion in the pelvis with free fluid ( a ) .
histopathological evaluation of the resected tumour showed a well - circumscribed mass with a dominant spindle cell tumour admixed with moderate chronic inflammatory cells .
the spindle cells were arranged haphazardly in a myxoid background but some areas were arranged in fascicles ( fig . 3a 
3c , inset top left ) and smooth muscle actin ( sma ) positivity ( fig .
the lesions being numerous no further treatment ( surgical , radiotherapy or chemotherapy ) was offered .
figure 3(a ) the periphery of the tumour with infiltration into fat ( h&e ) ; ( b ) spindle - shaped tumour cells in short interlacing fascicles admixed with moderate chronic inflammatory cells rich in plasma cells ( h&e ) ; ( c ) spindle cell populations with plasma cell infiltrate with the tumour cells showing cytoplasmic alk positivity ( inset : alk immunostaining ) ; and ( d ) some tumour cells are elongated with abundant eosinophilic cytoplasm ( h&e ) showing sma positivity ( inset : sma immunostaining ) indicating the myofibroblastic nature .
( a ) the periphery of the tumour with infiltration into fat ( h&e ) ; ( b ) spindle - shaped tumour cells in short interlacing fascicles admixed with moderate chronic inflammatory cells rich in plasma cells ( h&e ) ; ( c ) spindle cell populations with plasma cell infiltrate with the tumour cells showing cytoplasmic alk positivity ( inset : alk immunostaining ) ; and ( d ) some tumour cells are elongated with abundant eosinophilic cytoplasm ( h&e ) showing sma positivity ( inset : sma immunostaining ) indicating the myofibroblastic nature .
imft is a rare tumour of intermediate biologic potential as described in the recent who classification .
it has been variously called inflammatory pseudotumour , inflammatory fibrosarcoma , plasma cell granuloma , pseudosarcoma , and atypical fibromyxoid tumour .
initially described in the lungs and orbit as a reparative postinflammatory process , it has now been reported in many other extrapulmonary sites .
the pathogenesis of this condition has been variously described as an excess inflammatory response to infection , trauma , and surgery .
the abdomen is a relatively uncommon site for imft ; the liver is the organ most often involved .
historically these tumours were considered benign until meis and enzinger published a series of 38 cases , primarily intraabdominal , with follow - up data showing significant recurrences .
omental imft has been described as a distinct entity from the common inflammatory pseudotumour of the abdomen as pathologically it represents a form of clonal expansion rather than a postinflammatory response .
abdominal imfts are more confusing from both diagnostic and therapeutic aspects , as they are commonly mistaken for malignant tumours such as peritoneal carcinomatosis , sarcoma or lymphoma .
patients generally present with nonspecific systemic symptoms such as fever , weight loss , and vague abdominal pain .
specific symptoms depend on the size of the tumour and the mass effect on the adjacent structures .
laboratory evaluation may reveal hypergammaglobulinemia , false - positive widal test , increased esr , thrombocytosis , and microcytic anaemia .
on sonography they are seen as solid iso- to hypoechoic masses with vascularity on doppler .
on ct they are variously described as homo- or heterogeneous hypervascular lesions showing moderate to intense enhancement .
the top differentials include sarcoma , lymphoma , gist , castleman s disease and all causes of peritoneal carcinomatosis in the case of multiple masses .
it is important to differentiate as many of these close differentials need aggressive treatment with cytotoxic drugs , which may be harmful and could be avoided if a correct diagnosis is established .
histology findings of diffuse inflammatory infiltration , prominent plasma cells on microscopy and actin , vimentin positivity on immunohistochemistry confirm the diagnosis . after the diagnosis
features suggesting more aggressive behaviour include multifocal tumours , retroperitoneal location , infiltration of adjacent structures and incomplete excision .
pathologic features such as tumour cellularity , mitosis and necrosis do not correlate with outcome .
recurrences have been reported even after many years , so regular follow - up is essential for early diagnosis of tumour recurrence .
abstractinflammatory myofibroblastic tumour ( imft ) is a relatively uncommon neoplasm with unpredictable malignant potential known to occur anywhere in the body . 
 imft involving the omentum is a very rare entity with less than 15 cases reported so far . 
 we report a case of omental imft in a 15-year - old girl who presented with multiple peritoneal masses on imaging and the diagnosis was confirmed on histopathology . 
 in addition to its uncommon location , its presentation as multiple masses is extremely uncommon . 
 this uncommon presentation as multifocal masses needs to be distinguished from other causes of peritoneal carcinomatosis .