DONT TOUCH LESIONS TUMORS AND PSEUDOTUMORS BONE NOT

“DON’T TOUCH LESIONS” : TUMORS AND PSEUDO-TUMORS BONE NOT TO TOUCH M. GONGI, W. HARZALLAH, M. OMRI, M. MAATOUK, MA. JELLALI, W. MNARI, A. ZRIG, R. SALEM, M. GOLLI THE 5 th PAN ARAB CONGRESS OF RADIOLOGY MUSCULOSKELETAL : MK 13

INTRODUCTION (1) � “Don’t touch lesions” (DTLs) also called Don’t touch lesions “Leave me alone lesions” are imaging Leave me alone lesions abnormalities, often discovered incidentally, that a radiologist should readily recognize as benign and therefore should not be biopsied or surgically removed.

INTRODUCTION (2) � Many of these lesions are pathognomonic based on their imaging appearance and have a favorable prognosis (stabilization or regression after a period of evolution).

INTRODUCTION (3) � DTLs include the following: fibrous cortical defect (sometimes referred to as non-ossifying fibroma), periosteal desmoids, fibrous dysplasia, enchondroma, bone infarct, subchondral cyst …

Objectives � The aim of this study is to illustrate the imaging aspects of tumors and pseudotumors bone called “Don’t touch lesions” (DTLs), also termed “Leave me alone lesions”.

Materials and methods � In this presentation, we report six cases of DTLs collected in the radiology department of Fattouma Bourguiba Hospital of Monastir the last five years. � All patients were explored by radiographs and CT.

Results � We founded : - one case of cortical defect, - two cases of non-ossifying fibroma, - one case of giant enostosis, - one case of exostosis, - one case of enchondroma.

DISCUSSION 1 - Corical defect : - Cortical defects typically occur in children (6 – 11 years). Most are found incidentally when a radiograph is made for another purpose. - There is a male predilection by a ratio of 2.

- the lesion is asymptomatic and self limiting, the lesion is completely healing by adulthood. - Most cortical defects are in the distal ends of long bones (particularly common in the distal femur) and they are small, measuring less than 2 cm in diameter. - Importantly, there is no associated soft tissue mass.

- Radiographs and CT : - osteolytic cortical lesion, - outlined by a thin rim of sclerosis, - no involvement of the underlying medullary cavity, - no periosteal reaction, - no cortical disruption.

Corical defect : A small cortical osteolytic lesion of the distal tibia, surrounded by a thin dense border. There is no periosteal reaction and no cortical disruption.

2 - Non-ossifying fibroma : - The non-ossifying fibroma (NOF) is not a real neoformation, but an abnormal development of bone. - In the affected area, normal ossification does not occur during growth, but the area is filled with tissue connective. This is why the fibroid non-ossifying occurs in children.

- This abnormality tends to heal spontaneously by ossification at the end of growth. - The FNO is most often diagnosed in children (10 -15 years), the diameter is > 2 cm.

- Typically, it is localised eccentrically in the distal metaphysis of the femur. - In most cases, the NOF is asymptomatic and is a radiological finding. - On X-Ray imaging, we find an osteolytic lesion with a lobulated appearance. It is separated from the marrow by a sclerotic rim.

� Additional diagnostic workup is not indicated in typical cases. � Evolution : - The lesion almost always undergoes spontaneous resolution within a few years. - It knows no malignant transformation.

Non-ossifying-fibroma in a 12 -years-old boy : Osteolytic and multilobed lesion in the distal metaphysis of the femur. The lesion is eccentric with sclerotic border and net limit.

3 - Enchondroma : � It is a benign tumor that appears in the cartilage tissue found inside a bone and develops in the medullary cavity, arising from ectopic rests of hyaline cartilage. � Usually solitary, although it can occur as multiple lesions in syndromes.

� In most cases, enchondromas are painless and do not result in any adverse physical symptoms. � When a tumor is unusually large or when multiple tumors are present, however, a person can suffer from a bone fracture or deformity.

� It occurs mostly in 2 nd to 3 rd decade. � Enchondramas are most likely to appear in the small bones of the hands or feet. But, they can potentially affect any area of the body.

� Clinical findings › Usually asymptomatic. › May be associated with pain. � Imaging findings - osteolytic and well-defined lesion of the metaphysis. The cortex may be thinned. - Usually have some internal calcifications.

Enchondroma in small bones of the hand

4 - Exostosis : - The exostosis is a cartilaginous tumor, it develops especially in the metaphysis of long bones. - It is a well-differentiated bony overgrowth - The lesion is painless, but may have local complications: fractures (rarely

- Radiographs : - a bony outgrowth with a cartilage cap. - Sometimes, we find scattered popcorn calcifications.

Exostosis of the metaphysis of the lower femur

5 - Giant enostosis : - The nature of bone islands, or enostosis, is unclear. - Most bone islands are small, measuring 1 mm to 2 cm in diameter. - The most common sites of involvement are the femur, hand, humerus, pelvis, and ribs.

- Radiographs : Solitary bone island should be considered in patients with a small, sharply demarcated, asymptomatic, sclerotic lesion located within cancellous bone and having spiculated edges.

- Benign solitary bone islands are usually believed to remain stable over time, with no tendency toward growth.

Enostosis of right humerus : Radiography reveals a homogeneously dense, sclerotic lesion in the cancellous bone with distinctive radiating bony streaks creating a feathered or brush-like border.

Conclusion (1) � In bone and joint disease, it is sometimes difficult to distinguish a benign from a malignant bone lesion. Confusion cause a delay diagnosis or a high number of unnecessary biopsies.

Conclusion (2) � To avoid this, it is necessary to know the typical semiology of certain tumors and tumor like lesions which do not require histological confirmation.