LHERMIETTE DUCLOS DISEASE

T2-AXIAL IMAGE

T1-AXIAL IMAGE

FLAIR-AXIAL IMAGE

CONTRAST ENHANCED T1 AXIAL IMAGE

A 7 year old child presented with ataxia and dizziness. MRI of brain shows increased volume and abnormal signal in right cerebellar hemisphere with a characteristic "striated" appearance on T2. There is mass effect on the 4th ventricle. It shows mild patchy enhancement.

SALIENT RADIOLOGICAL FEATURES:

• It is also called dysplastic cerebellar gangliocytoma
• Well defined cerebellar lesion involving usually unilateral hemisphere. 
• It may be large and involve the entire hemisphere as in this patient.
• Widened cerebellar folia with a characeteristic "layered" or "striated"appearance on T2
• It is hypointense on T1 and may show striated appearance with alternating layers of isointense and hypointense signal
• Calcification may be seen rarely
• These may show bright signal on DWI due to T2" shine through"
• There is no diffusion disturbance on ADC map.
• Rarely, some lesions may enhance
• MRS may show elevated lactate. There is diminished NAA, choline and myoinositol

REFERENCES:


Jones BV: Dysplastic Cerebellar Gangliocytoma. Diagnostic Imaging Brain: First Edition. Amirsys: I-6-70, 2005.  

PEDUNCULATED SUBSEROSAL FIBROID

T2FS SAGITTAL IMAGE SHOWING MULTIPLE UTERINE FIBROIDS. ARROW SHOWS STALK OF PEDUNCULATED FIBROID

STIR CORONAL IMAGE

T1 CORONAL IMAGE

A middle aged female with menorrhagia showed multiple uterine fibroids on ultrasound. Ultrasound also showed a pelvic mass just above the uterus the origin of which could not be clearly ascertained. MRI was done which clearly showed its connection to the uterine wall by a narrow stalk thus confirming its origin.

SUBMUCOSAL UTERINE FIBROID

MRI of the pelvis in a 22 year young lady with infertility showed a large submucosal fibroid of uterus.

• Sagittal and coronal T2FS and STIR images show a large submucosal leiomyoma that arises from the posterior uterine wall and causes significant distortion of the endometrial cavity.
• These can be differentiated from polyps on the basis of signal characteristics and location. Leiomyomas are hypointense on T2. Also, the origin of the leiomyoma is from the uterine wall rather than endometrium.

MIRIZZI SYNDROME

T2 HASTE AXIAL IMAGE SHOWING IMPACETD CALCULUS IN CYSTIC DUCT

T2 HASTE CORONAL IMAGE SHOWING IMPACTED CYSTIC DUCT CALCULUS CAUSING BILIARY OBSTRUCTION. MULTIPLE CALCULI ARE SEEN IN THE GB.

T2 HASTE AXIAL IMAGE SHOWING DILATED BILIARY SYSTEM

T2 HASTE CORONAL IMAGE SHOWING BILIARY OBSTRUCTION

3D RECIST IMAGE SHOWING BILIARY OBSTRUCTION BY THE IMPACTED CALCULUS

 MIRIZZI SYNDROME:   

It is best seen on ultrasound or MRCP which show gall stone impacted in the cystic duct or GB neck causing narrowing of the common hepatic duct and dilated intrahepatic bile ducts.

REFERENCE: 

• Federle MP: Mirizzi Syndrome. Diagnostic Imaging Abdomen: Second Edition. Amirsys: III-2-48, 2010.

PARAMENISCAL CYST

PDFS SAGITTAL IMAGE SHOWING LATERAL MENISCAL TEAR

PDFS SAGITTAL IMAGE SHOWING PARAMENISCAL CYST

STIR CORONAL IMAGE SHOWING TEAR IN LATERAL MENISCUS AND PARAMENISCAL CYST

STIR CORONAL IMAGE SHOWING PARAMENISCAL CYST

AXIAL GRE IMAGE SHOWING PARAMENISCAL CYST.

MENISCAL AND PARAMENISCAL CYSTS:

HOW THEY ARE FORMED?

• They are usually formed as a sequel to trauma or degeneration which inititaes necrosis near the peripheral margin of the meniscus leading to mucoid degeneration and softening of the meniscal collagenous tissue with local accumulation of synovial fluid. 
• More often, this fluid extends to the meniscocapsular margin thorugh the meniscal tear displacing the capsule peripherally and thereby forms a paramenical cyst in the surrounding tissues.
•  Rarely, fluid accumulates locally within the meniscal tear and is contained within the meniscus.

IMAGING:

• On MR, intrameniscal cysts are seen as small fluid pockets within the meniscus. Adjacent horizontal cleavage tear may or may not be seen.
• Parameniscal cysts are seen as well defined ( often septated) fluid collections in continuity with horizontal cleavage tears or complex meniscal tears with horizontal component.
• They are usually hyperintense on all fluid sensitive sequences. However, cyst may show low signal sometimes on T2, either due to dessication or hemorrhage.
• If large, parameniscal cysts may cause bony erosion.

LOCATION:
-Medial> Lateral
-Most common site is along posteromedial aspect of medial meniscus
-Lateral meniscus cysts more commonly arise from its anterior and mid portions
-Although, medial meniscal cysts are more common, lateral meniscal cysts are picked up more often clinically.
-Lateral cysts are better defined and tend to remain close to the joint margin.
-Medial meniscal cysts are more tightly bound to the medial collateral ligament and hence, fluid accumulation is usually some distance away from the meniscal tear. However, a thin connecting stalk is usually seen between the cyst and meniscal tear.

DIFFERENTIAL DIAGNOSIS: It is very important to see the associated meniscal tear with connection to the cyst.

• Semimembranosus/ Pes anserine bursitis
• MCL bursitis

 REFERENCE:

•  McCarthy CL, McNathy: The MRI appearance of cystic lesions around the knee.Skeletal Radiol. 33:187-209, 2004.

 

PIGMENTED VILLONODULAR SYNOVITIS

SAGITTAL PDFS IMAGE SHOWING LARGE SYNOVIAL EFFUSION WITH SYNOVIAL THICKENING

SAGITTAL PDFS IMAGE SHOWING MULTIPLE NODULAR MASSES IN THE JOINT SPACE POSTERIORLY SHOWING HYPOINTENSE FOCI AND HYPOINTENSE RIM(  HEMOSIDERIN)

SAGITTAL PDFS IMAGE SHOWING SIMILAR NODULAR MASSES IN HOFFA'S FAT PAD.

STIR CORONAL IMAGE SHOWING HYPOINTENSE NODULAR SYNOVIAL THICKENING ON THE LEFT SIDE

AXIAL GRE IMAGE SHOWING "BLOOMING" OF NODULES/NODULAR SYNOVIAL THICKENING

AXIAL GRE IMAGE SHOWING BLOOMING OF NODULES

AXIAL GRE IMAGE SHOWING SIGNIFICANT BLOOMING OF SYNOVIAL BASED NODULES SUGGESTIVE OF HEMOSIDERIN CONTENT

SAGITTAL T1 IMAGE SHOWING ALMOST ISOINTENSE NODULES

49 year old patient presents with joint swelling and pain.
MRI reveals large synovial effusion with synovial thickening. There are multiple nodules within the joint which show hypointense areas on fluid sensitive sequences and bloom significantly on GRE suggestive of hemosiderin content.

PIGMENTED VILLONODULAR SYNOVITIS: 

• Benign, locally aggressive lesion
• Characterised by an abnormal synovial lining which is prone to hemorrhage with minor trauma resulting in repeated hemorrhagic effusions and iron deposition in the synovium and nodules
• There may be bony erosions and subchondral cysts with nodular proliferaition of synovium
• Patient presents with an insidious onset of painful joint swelling. Sometimes, torsion of nodules may cause sudden sharp rise in pain.
• Usually mono-articular
• There is a wide age range of presentation but commonest being 30-40 years.
• If untreated, repeated bleeding and synovial proliferation with erosions may lead to joint destruction. 
• GRE is most important sequence in MRI for its diagnosis as it elicits characteristic "blooming" of lesions.

DIFFERENTIALS:

INTRA-ARTICULAR NODULAR SYNOVITIS

•  May be completely identical to PVNS on MRI
• Generally show less effusion  and less hemosiderin than PVNS

 SYNOVIAL CHONDROMATOSIS

• generally loose bodies are seen on radiographs
• Sometimes conglomerate los signal masses on MRI in the synovium may be confused with PVNS but do not bloom on GRE

HEMOPHILIAC ATHROPATHY:

• Effusion with synovial proliferation
• Blooms on GRE
• However, morphologyis different with overgrown epiphyses/ metaphyses
• Also is often familial

REFERENCE:
Manaster BJ:Pigmented Villonodular synovitis( PVNS). Diagnostic Imaging Musculoskeletal: Non-Traumatic Disease: First Edition.Amirsys:I-134,2010.

Trevor Fairbank disease/ Dysplasia Epiphysealis Hemimelica

Figure 1

Figure 2

Figure 3

Figure 4

Figure5

Figures 1 to 5 ( T1, STIR coronal images) show cartilaginous intra-articular masses or overgrowth along with ossification arising from the medial aspect of left distal femoral, proximal tibial and distal tibial epiphyses with resultant deformity of the knee and ankle joints and limb length discrepancy. This fits into the classic form of Trevor Fairbank disease/ Dysplasia sepiphysealis hemilelica.

BACKGROUND AND HISTORY: Dysplasia epiphysealis hemimelica is a rare development disorder of epiphyses in children.
Mouchet and Berlot described it in 1926 in tarsal bones calling it "tarsomegalie".
In 1950, Treor described 10 cases naming it as "tarsoepiphyseal aclasis"
In 1956, Fairbank described 14 cases and coined the term "dysplasia epiphysealis hemimelica".

The disease is thought to be an osteochondroma of the joint.
It is mostly described in epiphyses and also occurs in seasmoid bones like the patella.
It is most commonly described in lower limb, mainly involving the knee and ankle.
It is hemimelic affecting the medial or lateral aspect of ossification centre, being twice as common in medial aspect as compared to lateral aspect.

EPIDEMIOLOGY:
 Prevalence  is 1 in 1 million
It is three times more common in boys
Non-hereditary  of unknown aetiology
First presents between 2-14 years of age

PRESENTATION:
Child usually presents with painless asymmetric firm swelling affecting one side of a lower limb joint.
There may be limb wasting, varus/ valgus deformity, anular deformities, joint locking, limb lengthening discrepancies etc.
Upper limb involvement and bilateral involvement have been described in literature but are extremely rare.

TYPES:
 Three types:Localized, classic and generalized

Localized variety: Single bone is affected, usually hindfoot or ankle
Classic variety:Affects more than 1 area in a single lower limb, usually knee and ankle. It accounts for more than two-thirds of the cases
Generalized form: Most severe form. Affects the whole lower limb from pelvis to foot.

Figure 1

IMAGING

Radiography: X-rays reveal mass with early focal ossification in medial or lateral side of the epiphysis (may be one or more). The lesions enlarge and ossify with bone maturation and may unite with the underlying bone. There may be premature closure of epiphysis with resultant limb length discrepancies.
There may be early secondary osteoarthritis .
There may be secondary involvement of metaphysis.
CT: shows anatomic relationship between mass and bone like cortical/ medullary bone continuity

MRI: shows anatomic relations better and also helps in identifying the tumour.
It shows signal intensity of lesion as  well as continuity with the primary site.

TREATMENT:
Observation or surgical
Surgery is only indicated if patient presents with severe pain and/ or deformity  or if there is locking of the joint.

RECURRENCE: is high after surgery

REFERENCES:
Araujo CR et al:Dysplasia Epiphysealis Hemimelica of Patella.Radiographics. 26:581-6, 2006
Bakarman KA: Dysplasia Epiphysealis Hemimelica.Medscape Radiology