Introduction

• Synovial biopsy is not normally required for routine diagnostic or therapeutic purposes in patients with established arthritis.

• But synovial biopsy provides tissue available for immunohistochemistry, electron microscopy, cytochemistry, cell culture and molecular biology which helps in understanding pathophysiological mechanisms of arthritis in details

• New approaches to the treatment, including monoclonal antibody treatment and cytokine blockade which target specific pathogenic factors in the synovium are being evaluated in clinical trials

Historical aspects• 1932 – Forestier first time obtained synovial

tissue• 1963 – Parker and Pearson developed the

technique using 14 gauge biopsy needle • 1970 – Kinsella et al in their study highlighted

synovial lining layers in RA• 1972 – Schumacher studied early features of

synovitis • 1990 – Arthroscopic biopsy was introduced

Normal Indications Tech of BX Processing Classification HP findings Peculiar findings Special stains: Gm, ZN, PAS,SM,PB Polarised microscopy, Xray diffraction, IR spectroscopy=

crystals Dark ground illumination= spirochetes in lyme ds

Indications • Infective synovitis – to differentiate Bacterial,

viral, fungal • Autoimmune and degenerative diseases – RA,

SPA, Osteoarthritis, SLE, Neuropathic • Crystal induced synovitis – Gout, Pseudogout,

Basic calcium phosphate, corticosteroids, Implant material

• Metabolic and inherited disorders – Hemochromatosis, Wilson’s disease, Onchronosis, Hemophilia

• Amyloidosis • Sarcoidosis • Tumour and tumour like lesions of synovium• Evaluation of treatment and treatment follow-

up

Normal histology• Gross : lines non – articular surface : pink , smooth & shiny : villi

microscopy• Synovial intima : type A cells : type B cells• Subintimal cells : mast cells : uncalassified

connective tissue cells : endothelial cells

Groud substance: mucoplysacharieds : hyaluronic acidCollagen fibers

Synovial biopsy• Definition - Procedure where a sample of joint

lining or synovial membrane is taken.• Synovial fluid examination is done prior to

synovial biopsy. Types :-1) Needle biopsy2) Orthoscopic biopsy3) Open surgical biopsy

Needle biopsy

• Most popular technique for diagnostic synovial biopsy is use of 14 gauge Parker – Pearson needle .

• Can be done hospital / clinic• Most common joint – knee• Other joints – shoulder, elbow, wrist.• With aseptic precautions biopsy area is prepared • Skin, subcutaneous tissue infiltrated with 1% lignocaine• Trocar is pushed into the joint space in suprapatellar pouch anterolaterally• Needle with an attached syringe is inserted to withdraw the synovial fluid

Needle biopsy• Then the biopsy needle is inserted• Hooked end of the biopsy needle withdraws

the sample• 5 to 7 samples from various sites are taken• Sample is kept in suitable fixative (formalin)• Aftercare :- Joint rested for 1 day

Normal activity resumed if there is no pain or swelling

• Complications:- Haemarthrosis, Infection Chances of injury to nerve or blood vessels

■ Disadvantage – Inadequate sampling

Orthoscopic biopsy • Advantages-provides larger tissue (granuloma,

tumour) under direct vision • Study of pathogenesis and effects of newer

therapeutic strategies• When the sample size is important as in studies

like in vitro experiments, cell separation or analysis of gene expression

• Disadvantages-more expensive and more complicated

Open surgical biopsy • Lesions which are deeper like focal granuloma ,

vasculitis in capsular vessels, tumours missed by needle biopsy and in small joint not suitable for needle biopsy.

Normal synovium and it’s immunohistochemistry

• Synovium is the inner layer of joint capsule

• Synovium formed when the primitive mesenchymal tissue cavitate forming a recognizable joint cavity.

• Synovium covers all surfaces of surfaces of joint spaces excepts articular cartilages and most cartilaginous structure

• The most superficial layer of synovium lines joint and also forms lining of tendon sheath

• Normally synovium appears smooth and transparent but may turns thick dull opaque cells with pathological changes

Normal synovium and it’s immunohistochemistry

Synovium

Intimal Subintimal

Synoviocytes

A

B

Loose highly vascular

Pecularities of synovium • The lining is discontinuous • Does not lie on basement membrane• Allows free exchange of solute and water

Functions of synoviumFunctions of synovium Phagocytic activity of type A synoviocytesPhagocytic activity of type A synoviocytes Lubrication of joint surfaces –hyaluronic acid Lubrication of joint surfaces –hyaluronic acid Regulation of movement of physiologically Regulation of movement of physiologically

important proteins and electrolytes in important proteins and electrolytes in conjugation with vascular and lymphatic conjugation with vascular and lymphatic channelschannels

Immunohistochemistry• T cells, macrophages, HLA DR+ cells, chlamydia

trachomatis (nucleic acid) with characteristically absense of ‘B’ cells

CD3+ T cells CD68+ macrophages

HLA DR+ cells

Infective synovitis• Hematogenous or spread from near by site (osteomyelitis) • BACTERIAL - Staph, streptococcus, gonococcus

Synovitis with dense neutrophilic infiltrate Staining and culture

• LYME DISEASE - Chronic papillary synovitis with synovial hyperplasia, fibrin deposition, mononuclear cell infiltration, onion skin thickening of arterial walls.Liederly stain/ silver stain

• Chronic Granulomatous synovitis -Tuberculosis - knee –Adult

Hip and spine -childrenM/E - Typical caseous epitheloid granuloma or non caseaous granuloma(HIV).Acid fast staning and culture

Infective synovitis Sarcoidosis-Non caseating granuloma with prominent

epitheloid cells& paucity of lymphocyte around granuloma FUNGI - Noncaseating granuloma (Cryptococcus, histoplasma) Staining and culture

VIRAL - Parvovirus,rubella, hepatitis C - Direct or as autoimmune reaction Culture and PCR

Rheumatoid Arthritis • Age - 40-70yr• Sex – F>M• C/F - Pain and swelling typically small joints of

hand• Morning stiffness• Arthritis of three or more joints • Symmetric arthritis • Rheumatoid nodules• Serum rheumatoid factor• Radiologically juxtaarticular osteopenia and bone

erosion and joint space narrowing

Pathogenesis

Rheumatoid Arthritis• Gross - Synovium is

oedematous thickened, hyperplastic with bulbous projections

• M/E – 1) Early - hyperplasia, hyperemia and infiltration by plasma cell and lymphocytes. Prominent lymphoid follicles, neovascularisation and fibrin depostion close to synovial lining and in stroma2) Pannus - causes destruction of articular cartilage

Role of immunohistochemistry• Diagnosis – Presence of CD3+, CD4+, CD20+,

CD38+ plasma cell, CD22+ B cells, lymphoid aggregates.

• αVβ3 integrin expression – synovial lining• αVβ5 integrin expression – subintimal layer• Early (1yr) vs late disease – synovial lining cell

layer increases in late disease• Prognosis –

No. of macrophages – in the synovial lining layer, if greater than 60% are macrophages – appearance of new erosions

MMP-2 – secreted by synoviocytes (FISH) associated with worst prognosis and appearance of new erosions.

Interleukin 10 – protective effect

Role of immunohistochemistry

• Evaluation of treatment – use of DMARD’s associated with histopathological changes in –- mononuclear cell population- adhesion molecule expression- cytokine production

Role of immunohistochemistry

Differential diagnosis – RA vs SPA

ααVVββ3 RA3 RA ααVVββ3 SPA3 SPA

ααVVββ3 SPA3 SPA

ααVVββ5 RA5 RA

ααVVββ5 SPA5 SPA

ααVVββ5 RA5 RA

Seronegative Spondiloarthropathy

• Ankylosing spondiloarthropathy• Reactive Arthritis (Reiter’s syndrome,

enteritis associated arthritis)• Psoariatic Arhritis • Arthritis Associated with inflammatory Bowel

diseases• Similar pathogenesis and histological picture

to RA but less intense inflammation and pannus formation and presence of entesopathy and different vascularisation pattern.

• IMMUNOHISTOCHEMESTRY - different integrin expression pattern than RA

Systemic lupus erythematosus

Multisystemic disease of autoimmune etiology F>M In 90% cases joint involved Non erosive synovitis with little deformities Histology similar to RA except for excessive fibrin

deposition,lesser degree of synovial hyperplasia

Osteoarthritis • MC joint disease• Degenerative joint disease• Primary or secondary ( trauma, hemochromatosis,

onchronosis)• Weight bearing joint like knee,ankle• C/F-Pain and swelling aggravated by work and

relived by rest• Radiology-joint space narrowing • Subchondral bone sclerosis• Formation of osteophytes/synovial hypertrophy/-

metaplasia• Chondromatosis-loose bodies in joint• GROSS-congested ,fibrotic synovium• M/E-Villus synovial hypertrophy with infiltration by

chronic inflammatory cells and subsequently pannus formation

Neuroarthropathy • Destructive joint disease• Sensory nerve damage is the key (syringomyelia,

tabes dorsalis)• M/E-presence of dead bone and cartilage within

synovium.osteochondromatosis leading to loose bodies within synovium

Crystal Induced Synovitis CrystalsCrystals

EndogenousEndogenous ExogenousExogenous

Gout (urate crystals)Gout (urate crystals)

Pseudogout (cppd)Pseudogout (cppd)

Basic calcium Basic calcium oxalate crystalsoxalate crystals

CorticosteroidCorticosteroid

Implant related Implant related changeschanges

Gout • Articular manifestation of systemic disease

1)Primary-idiopathic2)Secondary-myeloproliferative, lymphoproliferative disordersRenal failure, diuretics, Toxins-Lead, Alchohol

• Clinical features – 1) Asymptomatic hyperuricemia2)Acute gouty arthritis3)Intercritical gout4)Chronic tophaceous gout

• Gross - oedematous, congested synovium

Gout• Microscopy -

1) Acute - dense neutrophilic infiltrate small clusters of neutrophils containing monosodium urate crystals in cytoplasm with scattered lymphocytes,plasma cellsMonosodium urate crystals are needle shaped and negatively birefringent under polarized microscopy2)Chronic – Gross-hyperplastic, thickened and fibrotic M/E-presence of tophi surrounded by lymphocytes, plasma cells, foreign body giant cells

Pseudogout • Hereditary• Idiopathic• Secondary-

hyperparathyroidism, haemochromatosis

• Mechanism - altered activity of matrix protein that produce and degrades pyrophosphate resulting in its accumulation and eventual crystallision with calcium

• Crystals-chalky white friable deposit appears oval blue in histology

• positively birefrigent under polarized microscopy

Basic Calcium Phosphate Crystals

• Ca hydroxyappetite,tricalcium phosphate.alzarin red staining done to identify

Corticosteroid Crystals Corticosteroid Crystals Local or systemic treatment by corticosteroidLocal or systemic treatment by corticosteroid Fine granular faintly staining material in Fine granular faintly staining material in

synoviumsynovium

Tissue Reaction To Implant Material

Implant failure - Mechanical - Infection

Wear debries - metallic component of joint - high density polyethylene -

methyl methycrylate (support prosthesis)

Wear Wear debrisdebris

Tissue Reaction To Implant Material

Implant Implant materialmaterial

HistopathologyHistopathology

(Metallic) (Metallic) cobalt-chrome cobalt-chrome alloy Stainless alloy Stainless steel steel

Black coloured irregular Black coloured irregular granules within macrophages granules within macrophages & reactive tissue surrounding & reactive tissue surrounding prosthesis prosthesis

High density High density polyethylene polyethylene

Thread like element 10-20 Thread like element 10-20 micron within histiocytes & micron within histiocytes & giant cells apparent on giant cells apparent on polarized M/Epolarized M/E

Tissue Reaction To Tissue Reaction To Implant MaterialImplant Material

Implant Implant materialmaterial

HistopathologyHistopathology

Methyl Methyl methycrylate methycrylate

Dissolved in routine Dissolved in routine processing appears as processing appears as empty spaces with empty spaces with giant cells and foamy giant cells and foamy histiocytes containing histiocytes containing fine powdered cementfine powdered cement

Silicone Silicone rubber (small rubber (small joint) joint)

Bosselated and faintly Bosselated and faintly yellow particles which yellow particles which are highly refractile are highly refractile with histiocytic and with histiocytic and giant cell reactiongiant cell reaction

Inherited and Metabolic Diseases

• Haemophilia− chronic destructive disorder− haemophiliaA, haemophiliaB, vWD− C/F - Recurrent haemarthrosis− GROSS - hyperplastic red brown synovium− M/E - accumulation of hemosiderin laden macrophages

within synovial layer• Hemochromatosis

− AR, Increase uptake of iron , deposited in various tissue− Gross-brownish red synovium− M/E-hyperplastic synovium with proliferation of

fibroblast. Iron is deposited in synovial cells in perivascular location

• Hemosiderosis− hemosiderin laden macrophages within synovium

Onchronosis(Alkaptonuria) • AR,absence of homogentisic acid oxidase• Homogentesic acid polymers inhibits

hydroxylysine formation and chondrocyte metabolism ,cartilage destruction

• M/E-Inflammatory synovitis with shreds of blue black cartilage embedded in synovium

AMYLOIDOSIS • AL (Multiple myeloma) > AA Amyloid• In long term hemodialysis pt.- Beta 2microglobulin• Special staining and polarized microscopy

WilsonWilson’’s Diseases Disease AR, Multisystemic diseaseAR, Multisystemic disease Wrist joint McWrist joint Mc Synovium show mild hyperplastic changes Synovium show mild hyperplastic changes

with copper deposition with copper deposition

WhippleWhipple’’s Diseases Disease Presence of PAS+ material containing Presence of PAS+ material containing

macrophages within synovium with mild macrophages within synovium with mild hyperplasia. hyperplasia.

TUMOUR AND TUMOUR LIKE LESIONS

Synovial cysts (Baker’s Cyst)

• MC - knee joint (posterior capsule)

• Associated with RA or chronic inflammatory arthritis with increase intra articular pressure

• Cyst filled with clear or mucoid material

• M/E - cyst is lined by synovial lining and contains cartilage in its wall

• D/D - Ganglion cyst

Synovial Hemangioma • MC adult males• H/O recurrent hemarthrosis of long duration• Knee(mc),elbow, finger• GROSS-diffuse or nodular growth• M/E - Cavernous>Capillary>A-v hemangioma• D/D – pigmented villonodular synovitis, organizing

hemorrhage

Synovial Lipomatosis (Hoffa’s Disease)

• ADULT C/O pain and swelling in ant. compartment of knee, increase in infra patellar fat pad

• GROSS-synovium with marked papillary and yellowish appearance

• M/E-Mild hyperplasia of synovium with abundant fat extending to synovial lining cells. Mild chronic inflammation seen

Synovial Chondromatosis • M>F• AGE 30-50 yrs • MC – KNEE• GROSS - Nodules of

cartilage within synovium (loose bodies)

• M/E - foci of chondrometaplasia within synovium with cartilage cells showing cytological atypia (Binucleation)

• Recurs after excision• Rarely malignant

transformation to chondrosarcoma occurs

Tenosynovial Giant Cell Tumour (Benign synovioma)

W>M Young/middle age Wrist/finger tips GROSS - Single 1-3 cm.

well defined capsulated & lobulated grey white to yellow brown

Tenosynovial Giant Cell Tumour (Benign synovioma)

• M/E - Closely packed med sized polyhedral cells with variable admixture of giant cells contaning hemosiderin and fat, focal zones of hyalinisation seen

• Recurs after excision• Malignant

transformation to sarcoma occurs

Pigmented Villonodular Synovitis - (Xanthofibroma)

• M>F• 20-40yrs• MC-Knee• GROSS-villous

brownish yellow spongy mass

• C/S-Variegated appearance yellowish & brownish area with grey white fibrotic area

Pigmented Villonodular Synovitis - (Xanthofibroma)

• M/E-sheets of proliferating small ovoid or spindle shaped cells, multinucleated giant cells,hemosiderin deposit and aggregates of foam cells at the periphery of lesion & sparse lymphoplasmacytic infiltrate.abundant collagen deposition in long standing cases

• D/D – Hemosiderotic synovitis (hemophihlia / trauma)

Differential diagnosis with particular histological features

Synovial hyperplasia with lymphocytic ( CD4+, CD8+, CD3+), macrophages (CD68+), plasma cells, perivascular lymphocytic and fibrin deposition, lymphoid aggregates

RA SNA OA

Differential diagnosis with particular histological features

• Non caseating granuloma -– TB and Atypical MTB – Acid fast stain and culture- Fungal diseases - stain and culture- Sarcoidosis

Intense granulocytic response – - Septic arthritis – staining and culture- crystal induced synovitis – gout, pseudogout- Implant related changes

Heavy iron pigment deposition –- Hemophilia- Hemosiderosis and hemochromatosis- Pigmented villonodular synovitis- hemangioma, traumatic

Amyloid= AmyloidosisRh nodule= RACaseating granuloma= TBCrystals– needle neg biref= urate– Rhomboid pos birefringence= CPPD

Macrophages with Pas + material=Whipples ds

Ma, giant cells, foamy cells, hemosiderin= PVGS

Metaplastic cartilage islands= synovial chondomatosis

Evaluation of treatment and treatment follow up

• Biopsy sample taken before and after treatment • Evaluated for efficacy of several therapeutic

advances like use of monoclonal antibody to T cells, inhibition of proinflammatory cytokines, TNF-α, interleukin-β.

• Follow up is kept with effect on cellular infiltration, inhibition of adhesion molecule expression, decreased cytokine production

• Evaluation – macroscopic – orthoscopic- microscopic – conventional - digital image analysis – lining layers - T cells infiltration

Future challenges

• Increasing emphasis on need to recognise potentially erosive disease in patients presenting with early undifferentiated arthritis

• Recognisation of enhanced proinflammatory or degradative pathway or downregulation of inhibitory factors that participate in progression and prevention of arthritis

• Inclusion of pharmacogenomic and molecular techniques in analysis of synovial tissue from the patient with different categories and stages of arthritis presents some exciting possibilities of future research

Conclusion• Synovial biopsy is an easy, cheap and simplest

method of early diagnosis and quantification of diseases like rheumatoid arthritis, infectious metabolic tumour and tumour like lesions

• It provides window of opportunities to clincians to prevent early the potentially erosive diseases of joints