we report involvement of unusual site in ilio - acetabular region with breach in articular cartilage .
intra - operatively breach in acetabular roof was seen which was missed in the scan .
this case report emphasizes about the rarity of the lesion in this location and the rare chances of breach in articular cartilage of the joint .
bone desmoid tumor was an unknown entity until when jaffe hl reported a case in 1958 .
it is a locally aggressive benign tumor reported commonly in mandible and meta - diaphyseal region of long bones .
we report a case of desmoid tumor of ilio - acetabular region in a 40 year old female .
a 40 year old female came with complaint of pain in the left hip region which aggravated on squatting and climbing stairs .
radiological evaluation showed a lytic lesion in the left ilio - acetabular region , surrounded by a sclerotic margin superiorly .
mri scan was done which showed a well defined homogenous lytic lesion with no break in the cortex and no soft tissue involvement ( fig .
plain radiograph of pelvis with both the hips which shows a well defined lytic lesion over the left ilio - acetabular region
. there appears no obvious breach in the cortex or the articular margin a ct scan of the pelvis was taken to rule out any breach in the cortex .
there appears no obvious discontinuity through an ilio - inguinal incision the lesion was approached through inner table of ilium .
a defect on the roof of the acetabulum was found which was missed by the scan ( fig .
thorough curettage was done and the roof defect was reconstructed with a cortical graft harvested from the inner table of the ilium .
there appears a hollow curetted lesion within which a breach in the roof of the acetabulum is seen histopathological finding showed multiple spindle shaped fibroblast cells with small and elongated nuclei in the background of dense collagen fibres .
histopathology specimen picture showing spindle shaped fibroblast cells with small and elongated nuclei over a background of collagen fibers .
there appears no nuclear atypia or mitotic activity patient was kept non weight bearing for 3 months with gradual return to full weight bearing walking . at follow up of 20 months patient
is symptom free and xray showing no evidence of lytic lesion ( fig 5 ) .
however , on ct scan there appears a persistent lytic area which we suspect to be a recurrence ( fig 6 ) .
hence patient is kept on regular follow - up . a 20 month post operative x ray picture showing well maintained articular margin and the joint space .
the lytic lesion seems filled up ct scan of the hip taken at 20 month post op , however shows lytic lesion anteriorly which seems to be a recurrence
few cases have been reported since then and common occurrence being in mandible and meta - diaphyseal region of the long bone .
recognition of desmoplastic fibroma is important because on radiology and histology , the lesion may be mistaken for an indolent , benign fibrous lesion or more aggressive spindle - cell sarcomas .
it commonly occurs in the age group between the adolescent to 40 years with no specific sex predominance .
patients commonly come with complaint of pain ; however there are few reported cases of pathological fracture especially those involving tibia and femur .
the lesions are well defined with no sclerosis or periosteal reaction except if there is associated pathological fracture . if a soft tissue lesion is invading onto the bone , they are eccentric in position with sclerosis due to endosteal bone formation .
significant t2 shortening of a non - sclerotic fibro - osseous lesion should place desmoplastic fibroma high among the diagnostic considerations .
radiologically they have to be differentiated from giant cell tumor , fibrous dysplasia ( long bone lesions ) , fibrosarcoma , brown tumors , and chondromyxoid fibroma and hence a tissue diagnoses is must .
the differentiation from a low grade fibrosarcoma is difficult though . as these are rare tumors , there is no standard protocol for treatment of these lesions .
all kinds of procedures like intralesional , marginal or wide resection are reported as a treatment .
but if wide resection would result a major functional deficit , an attempt of intralesional curettage with bone grafting seems warranted .
desmoid fibroma of ilio - acetabular region is very rare hence a great sense of suspicion is required for the appropriate management .
this case report emphasizes about the rarity of the lesion in this location and the chances of breach in articular cartilage of the joint .
desmoid tumor , though rare , should be kept as one of the important differentials for the lytic lesion around pelvis .
one should also define whether there is any associated cortical or articular margin breach ( as seen in our case report ) and then decide further management regarding reconstruction .
 introduction : desmoid tumor of bone is a rare benign tumor . it is reported commonly in mandibular and meta - diaphyseal region of long bones . 
 we report involvement of unusual site in ilio - acetabular region with breach in articular cartilage.case report : a 40 year old female presented with pain in the left hip . 
 radiologically , a lytic lesion at ilio - acetabular region was seen . 
 intra - operatively breach in acetabular roof was seen which was missed in the scan . 
 curettage and defect reconstruction was done . 
 histopathology reported as desmoid tumor . 
 20 months post - operatively patient was symptom free.conclusion:desmoid tumor is a rare bone tumor . 
 this case report emphasizes about the rarity of the lesion in this location and the rare chances of breach in articular cartilage of the joint . 
 the chances of recurrences are high with intralesional curettage . 
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Introduction
Case Report
Discussion
Conclusion