Disclosures I have nothing to disclose. Neoplastic joint disease - - PowerPoint PPT Presentation

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Neoplastic joint disease

(and tumor-like conditions)

Andrew Horvai, MD, PhD Clinical Professor, Pathology

Disclosures

I have nothing to disclose.

Introduction

• Virtually any neoplasm of bone can secondarily involve joint

imaging essential to exclude

• Primary neoplasms of joints
• Tend to involve cavitated joints (synovium)
• Most are benign
• Masses of nonsynovial joints are usually degenerative
• Synovial neoplasms
• Lipoma(tosis)
• Chondroma(tosis)
• Hemangioma
• Tenosynovial giant cell tumor
• “Synovial” sarcoma

Synovial lipoma(tosis) (Lipoma arborescens)

• Clinical
• Knee > wrist, hip
• Slow, painless swelling
• Recurrence very rare
• Imaging
• Does not erode bone
• MRI – increased nodularity and fat signal in synovium
• Pathology
• Nodular, bright yellow synovium
• Replacement of subsynovial connective tissue with mature adipose tissue,

villous architecture

• May contain lipoblasts
• Lined by single layer of synoviocytes
• Differential diagnosis
• Normal synovial fat (has more collagen between fat cells)
• Atypical lipomatous tumor (very rare in synovium)
• Hoffa’s disease (probably same lesion, located in infrapatellar fat pad)

2 Synovial lipoma

T2 FS

Does not erode bone

1 cm

Synovial lipomatosis Synovial lipomatosis Synovial lipomatosis

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Synovial chondroma(tosis)

• Clinical
• 3rd-5th decade
• Knee, shoulder, large joints
• Rare recurrence
• Malignant transformation ~1%
• Imaging
• If calcified, plain film shows multiple cloudy or ring calcs
• Can erode cortex
• MRI, lobulated, bright on T2
• Pathology
• Multiple nodules of blue cartilage, + lined by synovium
• Clustering of chondrocytes
• Nucleomegaly and binucleation common, mitoses absent
• Necrosis OK
• Differential diagnosis
• Chondro-osseous loose body
• Soft tissue chondroma (closely related if not same)
• Synovial chondrosarcoma (secondary chondrosarcoma)

Synovial chondromatosis

Synovial chondromatosis: multiple nodules, eroding articular cartilage Synovial chondromatosis: clustering + endochondral ossification

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Synovial chondromatosis Synovial chondromatosis Synovial chondromatosis

Synovial chondromatosis, secondary chondrosarcoma

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Synovial chondromatosis, secondary chondrosarcoma

Chondro-osseous loose body

Chondro-osseous loose body: Hyaline and fibrocartilage, irregular calcifications Chondro-osseous loose body

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Synovial “hemangioma”

• Clinical
• Vascular malformation not a true vascular neoplasm
• Children > Adults, knee most common
• Most asymptomatic, or slow swelling, decreased range of motion
• Cured by excision
• Imaging
• Plain film may suggest effusion (nonspecific)
• MRI – T2 bright serpentine structures, fluid-fluid levels
• Pathology
• Vascular channels of varying caliber, increased density beneath normal or

hyperplastic synovium

• Increased fat
• No atypia or mitoses
• Differential diagnosis
• Chronic hemarthrosis (grossly)
• Diffuse tenosynovial giant cell tumor (imaging)

T2 FS

Synovial “hemangioma” Synovial “hemangioma”

Synovial hemangioma

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Synovial hemangioma Synovial hemangioma

Tenosynovial giant cell tumor

• Clinical
• Adults, knee, wrist, digits, shoulder
• Slow growing joint swelling, locking
• Recurrence risk ~ growth pattern
• Imaging
• Soft tissue mass, may erode bone
• “Bloom” on MRI, T2 bright, sometimes T1 bright also
• Pathology
• Polymorphic: Histiocytes, multinucleated giant cells, spindly fibroblasts,

siderophages, foam cells, chronic inflammation

• Central fibrosis in older lesions
• Mitoses may be brisk not atypical
• Differential diagnosis
• Giant cell tumor of low malignant potential (soft tissue analog of GCT of

bone)

• Chronic hemarthrosis
• Malignant tenosynovial giant cell tumor

Localized Diffuse Gender M > F F > M Joints Small, hand Large, knee Size < 5 cm >10 cm Recurrence 4-30% 30-50% IHC CD68, desmin CD68, desmin

Tenosynovial giant cell tumor

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Diffuse, T2 FS Localized, T2 FS

Tenosynovial giant cell tumor

Horvai A, Robbins Basic Pathology, Elsevier, 2017

Tenosynovial giant cell tumor: Diffuse

Tenosynovial giant cell tumor: Diffuse Tenosynovial giant cell tumor: Diffuse

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Tenosynovial giant cell tumor: diffuse Tenosynovial giant cell tumor: diffuse

Tensynovial giant cell tumor: localized

Tenosynovial giant cell tumor: diffuse Tenosynovial giant cell tumor: localized

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Tenosynovial giant cell tumor: localized Tenosynovial giant cell tumor: localized Tenosynovial giant cell tumor: localized Tenosynovial giant cell tumor: localized

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Tenosynovial giant cell tumor: localized Tenosynovial giant cell tumor: localized Tenosynovial giant cell tumor: desmin

Tenosynovial giant cell tumor

• Same genetic abnormality in both subtypes (COL6A3:CSF1)
• Diffuse and localized type related to anatomic compartment

rather than biology

• Provides mechanism of pathogenesis analogous to giant cell

tumor of bone

West RB et al. PNAS, 2006 103(3) 690–695.

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Synovial sarcoma

Jones SF, Whitman RC. Ann Surg. 1914;60(4):440-50.

Synovial sarcoma

• Clinical
• Young adults (peak), wide age range
• 80% extremity, knee common but not intra-articular, can arise anywhere
• 5 year survival 36-76%, chemotherapy + surgery
• Pathology
• Monophasic (70%): uniform spindle cells, short fascicles, herringbone
• Biphasic (30%): uniform spindle cells + pseudoglands
• Poorly differentiated (<1%): small round blue cell tumor
• Hyperchromatic nuclei, paradoxically low mitoses
• Branching vessels, calcification
• IHC
• Keratin, EMA – usually focal and patchy
• S100 in ~30%, SOX10 <10% (usually intraneural synovial sarcoma)
• CD34 negative
• Genetics
• t(X;18), SS18-SSX1 –SSX2, -SSX4 fusion

Monophasic synovial sarcoma Monophasic synovial sarcoma

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Monophasic synovial sarcoma Monophasic synovial sarcoma Biphasic synovial sarcoma Biphasic synovial sarcoma

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Monophasic synovial sarcoma

Poorly differentiated synovial sarcoma

EMA Keratin SS18 break apart FISH Keratin

Take-home messages

• 1. Do not diagnose diseases of joints (especially synovial

chondroma(tosis) without reviewing imaging. It could be a bone tumor.

• 2. Just because it’s villous and synovial it does not mean it is

Pigmented Villonodular Synovitis

• 3. Do not over-diagnose a desmin positive PVNS as

rhabdomyosarcoma

• 4. Synovial sarcoma is a sarcoma but has nothing to do with

normal synovial cells