BIZARRE PAROSTEAL OSTEOCHONDROMATOUS PROLIFERATION (NORA'S - PowerPoint Presentation

Slide1

BIZARRE PAROSTEAL OSTEOCHONDROMATOUS PROLIFERATION (NORA'S LESION) A REPORT OF 4 CASES

 J. BEN NASR, M. CHELLI BOUAZIZ, W. TURKI, L. ABID, MH. JAAFOURA, MF. LADEB

MUSCULOSKELETAL : MK 24Slide2

INTRODUCTION

Bizarre parosteal

osteochondromatous

proliferation

(

BPOP) was first described by Nora in 1983

Occurs mostly on small bones of hands and feet

Rare benign lesion that can be confused with other benign and malignant conditions

We present four cases of BPOP

outlinig

clinical, radiological and histological findings.Slide3

PATIENTS AND METHODS

Retrospective study of four radio-clinical observations of histologically confirmed NORA's lesions , collected in our insitution

1 man and 3 women aged from 24 to 52 years

The patients were investigated by radiographs (n = 4), ultrasound (n = 2), CT (n = 1) and MRI (n = 1)Slide4

Case 1 :

52 year old male5 year history of mass on the palmer aspect of the right index

No history of trauma

CASE REPORTSSlide5

Fig 1b:

Ultrasound of the right index: calcified lesion without modification in adjacent soft tissues.

Fig 1a :

Anteroposterior and lateral radiographs of the right index show a juxta-cortical calcified lesion of the middle phalanx with adjacent cortical erosion Slide6

Case 2

A 24 year-old womanNo significant medical history

Nine months history of a hard mass of the second phalanx of her right

medius

No concept of trauma

CASE REPORTSSlide7

Fig 2a 

:

Lateral radiograph of the right medius shows a calcified well circumscribed lesion, developed at the palmar aspect of the middle phalanx base, with no adjacent bone or soft tissue abnormalitySlide8

Fig 2b:

High resolution ultrasound of the right medius in transversal view: calcified lesion surrounded by a thin hypoechoic cap

Fig 2c:

Transversal CT view of the right hand in bone algorithm: Surface bone lesion with large cortical base. There is no continuity between the lesion and the underlying bone cortexSlide9

Fig 2f

:

Cartilaginous prolifération made of chondrocytes with irregular morphology (bizarre cells) (HE x400)

Fig 2e 

: Tumoral proliferation with osseous( ), cartilaginous ( ) and fibrous ( )components( HE x 200)

Fig 2d:

Gross pathology. Well circumscribed pediculated mass, of hard consistance and white greyish colourSlide10

Case 3 :

A 38 year old woman Swelling and discomfort affecting her right forefoot.

No significant past medical history nor history of trauma

On examination, there was a

fusiform

swelling regarding the proximal phalanx of the third right toe.

CASE REPORTSSlide11

Fig 3:

Antero posterior radiograph of the right foot shows an ossified mass developed from the proximal phalanx of the third toeSlide12

Case 4 :

Woman of 45 years, tailor, right-handedHistory of benign breast tumor

Swelling and pain in the distal phalanx of the right medius

CASE REPORTSSlide13

Fig 4a: Lateral radiograph of the right medius shows a calcified bone surface lesion developed from the palmar surface of the distal phalanx with soft tissue swelling but no adjacent bone abnormalitySlide14

Fig 4b

: Sagittal MRI view of the right hand on T1 W sequence, T1W sequence after intravenous Gadolinium injection and T2 W sequence.The lesion shows a homogenous low T1 signal and high T2 Signal with moderate enhancement after intravenous Gadolinium injection.Slide15

Fig 4c

: Microscopic view(HE x 200) showing bone trabeculae associated with fibrous tissue

Fig 4d:

Microscopic view (HE x 400) showing chondroïd tissue made of chondrocytes of irregular size sometimes binucleated ( )Slide16

RESULTS

The lesions were palmar

(3 cases) and plantar (1 case) swelling , painful in 3 cases

Radiographs showed a calcified

juxtacortical

well

marginated

mass,

of

less

than

3 cm,

attached

to the

external

face of the cortical

bone

of a

phalanx

High resolution ultrasound showed a calcified lesion surrounded by a thin

hypoechoic

cap

On CT, the lesions had a wide base of implantation on bone.

MRI showed a

juxtacortical

lesion,

hypointense

on all sequences with an

intralesional

enhancementSlide17

RESULTS

All patients underwent

excisional

biopsy of the lesion

Histopathological

examination confirmed the diagnosis in all cases

Two patients were lost to follow up after surgery

The other two had a postoperative follow-up of 6 and 18 months, without clinical or radiological recurrenceSlide18

BPOP is a benign and rare surface lesion of bone

BPOP affects males and females equally

There can be a wide range of age presentation, though the lesion is most common in the third and fourth decade

Epidemiological

features

:

DISCUSSION Slide19

Usually affects the proximal and middle phalanges, and the metacarpal or metatarsal bones

The hands are 4 times more commonly affected than the feetUnlike subungual

exostosis

, this lesion is rarely found on distal phalanges

BPOP is less commonly found in other sites and have been reported in unusual locations such as the

humerus

and the clavicle

Location :

DISCUSSION Slide20

The typical clinical presentation is a painless swelling that grows over a period of months to years

On examination, BPOP is a firm mass, usually small, ranging from 0.4 to 3 cm in diameter and do not involve the overlying skin

Joint motion may be limited when the lesion is located at the end of a bone

Clinical

features

:

DISCUSSION Slide21

BPOP is a well-marginated

, calcified or ossified mass arising directly from the cortical surface of the underlying boneIt is generally attached by a broad base and the underlying cortex is intact

There is no

periosteal

new bone formation. However, cortical erosion has been reported

Radiographs

:

DISCUSSION Slide22

Fine cut Computed Tomography scan shows

a mass with well defined margins, intensely calcified or ossified, arising from the cortex of the affected boneCT is, better than radiographs in showing the absence of continuity between the cortex and the medullar cavity of the bone and the absence of cortical flaring in this affected bone

CT Scan :

DISCUSSION Slide23

BPOP displays homogenous low signal intensity on T1 weighted sequences with uniform enhancement following the IV administration of gadolinium

On T2 weighted images, the lesion has a high signal, slightly increased signal centrally compared with its periphery being of higher signal intensity.

MRI show neither

periosteal

reaction nor

medullary

involvement but normal underlying bone and adjacent soft tissues

MRI :

DISCUSSION Slide24

BPOP has an atypical histological appearance

The lesion contains highly cellular, disorganized and irregular cartilage, proliferation of bizarre fibroblasts and disorganized bone with spindle shaped fibroblasts in the intertrabecular space

The presence of an unusual form of calcified cartilage that stains blue on

hematoxylin

and eosin (H & E) stain is characteristic

Pathological

findings

:

DISCUSSION Slide25

Mitotic figures are often seen, but neither atypical mitosis nor cytological

atypia is seenBPOP may also be confused with osteochondromas

but

osteochondromas

are rare in the hands (4% of

osteochondromas

)

Moreover, in the lesion of Nora, there is no

continuity between the

medullary

canal and cortical bone with the underlying bone

bone

Pathological

findings

:

DISCUSSION Slide26

Florid reactive periostitis

Ossified hematomaMyositis ossificans

Stress fracture with extensive callous formation

Parosteal osteosarcoma

Peripheral chondrosarcoma

Differential

diagnosis

:

DISCUSSION Slide27

No treatment is required if a BPOP is asymptomatic, as the lesion is benign

If the patient is symptomatic (pain or compromised function), definitive treatment is by surgical excision with wide margins

Treatment

:

DISCUSSION Slide28

DISCUSSION

BPOP

has a remarkable tendency to recur(51%)

Time interval between excision and local recurrence ranges from 2 months to 2 years

No malignant transformation, metastases or deaths have been described in patients with BPOP

Because of its high local recurrence rates and the lack of adjuvant therapy options, Nora's lesion requires long-term follow up

Local

Recurrence

: Slide29

CONCLUSION

The NORA’s lesion is benignImaging and

and

histological features allow the distinction of this rare entity from true bone tumors