MSK radiology: DDx and disease properties

FEGNOMASHIC

Fibrous dysplasia
EG, Enchondroma
GCT
NOF
Osteoblastoma
Mets, Myeloma
ABC
SBC
Hyperparathyroidism
Infection
Chondroblastoma

FEEMHI

Fibrous dysplasia
Enchondromas
EG
Mets, myeloma
Hyperparathyroidism
Infection

FAME

Fibrous dysplasia
ABC
Mets, myeloma
Enchondroma, EG

COGEM

Chondroblastoma (if <40 yo)
Osteomyelitis
GCT, geode
EG
Mets/myeloma (if >40yo)

OAT

Osteoblastoma
ABC
TB

CANES

Chondroblastoma
ABC
NOF
EG
SBC

FILE

Fibrosarcoma
Infection
Lymphoma
EG
osteoid osteoma (mimic)

CARD and T

CPPD
AVN
RA
DJD
Trauma

If over 40, METS (P,B,HL)

20-40 yo:
chondroblastoma
ABC
NOF
EG
SBC
fibrous dysplasia
infection
HPT (healing brown tumor)
osteoid osteoma
giant bone island

Fibrous dysplasia
enchondroma
cartilaginous tumor

Ewing's
Osteosarcoma
Lymphoma
Osteomyelitis
EG

Osteosarcoma
Ewing's sarcoma
Lymphoma
Osteomyelitis

Osteosarcoma
Lymphoma
Ewing's
MFH
Osteomyelitis

Myeloma/mets
Lymphoma
Chondrosarcoma
Fibrosarcoma/MFH
Osteosarcoma
Osteomyelitis

Ewing’s and other round cell CA
infection
EG

infection
mets, myeloma
MFH
reticulum cell sarcoma

MFH
liposarcoma
synovial sarcoma
synovial osteochondromatosis
PVNS
hemangiomas

fibrosarcoma, OSA, MFH

OSA

SCC

OSA, chondrosarcoma, MFH

fibrosarcoma, MFH

chondrosarcoma

chondrosarcoma

chondrosarcoma

- osteoporosis
(metacarpal cortex < 1/4-1/3 of metacarpal)
- radiation
- hemangiomas

stress fracture
infection
osteoid osteoma

PBKTL
P – mostly blastic
B – mixed
K – purely lytic
TL – mostly lytic

joint space narrowing (asymmetr)
subchondral sclerosis
osteophytes
subchondral cysts
lack of osteoporosis or erosions

TMJ
SI
AC
pubic symphysis

-hands – proximal. Ulnar dev.
-bilaterally symmetric
-marginal erosions (incl uln styloid & triquetr)
-periart & diff osteoporosis, subchondral cysts
-ST swelling
-jt space narrowing (JSN)
-carpal instability, rotator cuff tear
-distal clavicle resorption
-protrusio acetabuli, A-a subluxation
-2˚ DJD – severe JSN >> sclerosis & osteophytes

- NO periosteal rxn
- mention adamantinoma if in tibia or jaw
- Typical: pelvis, prox femur, ribs, skull
- "long lesion in long bone"
- expansile medullary lytic lz w/ground glass; well-def sclerotic margin
- bowing deformities; base of skull sclerotic
- hot on bone scan
- cherubism-mandible & maxilla
- craniofacial -facial & frontal bones
- pseudoarthrosis of tibia
- Mccune Albright -polyostotic FD with café-au-lait spots &precocious puberty)

- must have Ca++ expt in phalanges
- no periostitis
- tubular bones
- chondroid calcifications
- endosteal scalloping
- pain is malignant
- Ollier’s enchondromatosis, Mafucci’s enchondromatosis with multiple ST hemangiomas)

- age<30
- lytic lesion can look aggressive
- skull lesion beveled-edge appearance
- sequestrum
- floating tooth
- vertebra plana
- lung dz, pituitary, RES

- epiphyses closed
- epiphyseal & abuts articular surf in long bones
- eccentric
- well-def NONsclerotic border except flat bones
- long tubular bone> spine/sacrum, 50% @knee

- age<30
- no periostitis
- cortically based
- metaphysis
- also mention chondromyxoid fibroma

- age<30, painful
- expansile, eccentric
- fluid-fluid levels on MR
- post elem spine, metaph long bones, pelvis
- also mention osteoblastoma

- age<30
- central, no periostitis
- prox humerus, prox femur, calcaneus
- fallen fragment sign

- age>40
- plasmacytoma in ilium & sacrum,
- cold on bone scan; do skel survey
- vert bodies destroyed before pedicles
- axial skeleton, long bones, punched-out lytic lesions, generalized osteopenia

- ill-defined intramedullary metaphyseal mass
- extends through cortex
- osteoid or chondroid matrix
- aggressive periost rxn (Codman or sunburst)
- telangiectatic form - purely lytic, mimics ABC
- parosteal form - low-grade, seen in post distal femur w/ more mature ossification centrally

bony ankylosis
proliferative new bone formation
predom axial (spinal)
syndesmophytes

- AS (bamboo spine, Andersen lesion and pseudoarthrosis),
- IBD (like AS)
- psoriasis (distal jts, sausage digit, pencil-in-cup, acroosteolysis, proliferative erosions, STS, periostitis, ankylosis, arthritis mutilans deformities, heel spur w fuzzy margins
- Reiter’s syndrome (like psoriasis but feet>hands, IP joint great toe),
- DJD, gout
- infection
- HPT

bilat + symmetric SIJ + marginal symmetric syndesmophytes – usually AS or IBD
unilateral or asymmetric SI jt – NOT AS and IBD, consider psoriasis and Reiter’s

- DJD (superolateral migration in hips, medial compartment of knee most affected),
- RA (axial migration in hips),
- CPPD
- AS (resembles RA)
- PVNS, synovial osteochondromatosis,
- infection (S. aureus most comm, Salmonella in sicklers; + effusion, + joint destruction, crosses vert discs, periosteal rxn, bone destruction, Brodie’s abscess is well-defined lytic lesion with thick sclerotic border, sequestrum)
- amyloidosis (nodular synovitis with erosions resembling RA)
- ochronosis (DSN with vacuum, disc calcifications, generalized osteoporosis, secondary OA)

Distal – OA, psoriasis, Reiter’s
Proximal – RA, CPPD
Ulnar styloid - RA

- Primary OA (middle-aged F in hands only, 1st CMC, gull-wing erosive pattern)
- RA
- multicentric reticulohistiocytosis (mult erosions mostly phalanges NO osteoporosis)

CHRIST:
- Crystal arthropathies
- Hemophilia
- RA
- Infection
- Synovial (synovial osteochondromatosis, PVNS)
- Trauma

- erosions w/ sclerotic borders or overhanging edges
- soft tissue nod (can calcify w/ renal failure)
- in hands –random dist, NO osteoporosis
- podagra (1st MTP jt)
- often have chondrocalcinosis
- preserved joint space
- olecr/prepatellar bursitis

HITDOC:
- Hurler’s
- Infection
- Trauma
- Dyschondrosteosis
- Osteochondromatosis
- Chromosomal anom (Turner’s)

CHONG
- Craniometaphyseal dysplasia
- Hemoglobinopathies
("hair on end" skull
extramed. hematopoiesis)
- Osteopetrosis
- Neimann-Pick
- Gaucher's

DJD
CPPD
Gout
multi. reticulohistiocytosis
PVNS
synovial osteochondromatosis

- hemophilia (hemarthrosis, 2˚ OA, wide intercond notch, big trochlear notch, subchondral cysts; pseudotumor – ST mass w/ adj bone destruction, hematoma, Ca++ common)
- JRA (diff ankylosis of post articular joints, periosteal new bone, STS, short metacarp)
- paralysis

ASEPTIC
-Anemia (SC), Amyloid
-Steroids
-Ethanol
-Pancreatitis, Pregnancy
-Trauma
-Idiopathic (L-C-P)
-Caisson dz, CVD

steroids
RA
DM
HPT
gout

familial
chondroectodermal dysplasia
trisomy 13
Meckel-Gruber

VACTERL
Holt-Oram syndrome
Thrombocytopenia-absent radius syndrome

PINCH FO

Psoriasis
Injury (thermal)
Neuropathy (DM, leprosy)
CVD (Raynaud's, scleroderma)
Hyperparathyroidism
Familial (Hajdu-Cheney)
Other - PVC tox

- Trauma
- HPO (pain, long bones; lung/ pleural CA, mets, chron PNA)
- Venous stasis (legs)
- Thyroid acropachy (post thyroidectomy, metacarpals & phalanges, esp ulnar aspect of 5th metacarpal)
- Pachydermoperiostosis (like HPO but rarely painful)

LIMP
– Lymphoma
- Infection
- Mets, myeloma
- Paget’s

Neoplasm
Mets, Myelofibrosis
Mastocytosis, Lymphoma
Congenital
Craniotubular dysplasia
Osteopetrosis
Pyknodysostosis
Sickle cell
Metabolic
Paget's
Renal osteodystrophy
Fluorosis
Hypervitaminosis A&D

SCALP NIT
-Scurvy (dense metaph lines)
-Caffey's (tib, ulna, mandib)
-A hypervitaminosis
-Lymphoma/leukemia
-Physiologic, prostaglandins
-Neuroblastoma
-Infection
-Trauma

bladder exstrophy
infection
mets
trauma
pregnancy

osteoporosis and ST wasting in the hands, usually no erosions

SLE - ulnar deviation of phalanges, nonerosive, resembles Jaccoud’s arthropathy

Scleroderma - ST Ca++, acroosteolysis, severe resorption of 1st CMC with radial subluxation of 1st metacarpal

Dermatomyositis - widespread ST Ca++, radial subluxation of IP joint of thumb

primary HPT
gout
hemochromatosis
(DJD 2nd-4th MCP jts with squaring of metacarpal heads with drooping osteophytes, generalized osteoporosis)

- pain
- cartilage Ca++ (knee, triangular fibrocartilage of wrist, pubic symphysis)
- joint destruction from secondary DJD (shoulder, elbow, radiocarpal jt, patellofemoral jt)
- subchondral cysts, can mimic gout

SCD
HPT
Paget’s
FD
TS
infection
mets, myeloma
EG, epidermoid
hemangioma

- Enchondroma
- Glomus tumor (pain, terminal phalanx)
- Epidermoid inclusion cyst
- Mets
- Infection
- Sarcoid
- Erosive arthropathy

- Growth recovery lines
- Lead
- Healing rickets
- Scurvy

- shortened long bones w/ narrowing of interpedicular distance in caudal direction
- posterior vert body scalloping

- thickened cortical new bone like “dripping candle wax”
- follows sclerotome

- flattened vertebral bodies with anterior beak
- flared iliac wings and broad femoral necks
- pointed proximal 5th metacarpal base w/notch look to ulnar aspect
- posterior vertebral body scalloping

- osteochondromas
- metaphyseal
- lesion grows away from joint, undertubulation, knees, proximal femur, axial more prone to degeneration

- pain, age<30
- lucent nidus surr by reactive sclerosis in cortex of long bone
- can be on concave side of painful scoliosis
- “double density” sign on bone scan

- multiple 2-3mm thick linear bands of sclerotic bone aligned parallel to long axis of bone
- asymptomatic

- asymptomatic
- mult small sclerotic densities @ ends of long bones & pelvis
- hereditary

- skull thickening
- enlarged sinuses & sella
- hypertrophied terminal tufts w/ spade appearance
- posterior vertebral body scalloping
- elongated & wide vert bodies
- heel pad thickening

- pain
- self-limited
- low T1 signal
- hot on bone scan

- asymptomatic
- proximal femur, fibula, calcaneus
- may have central calcified nidus

- Mets
- Chordoma (sacral, clivus, vert body - expansile lytic lz w/ST component)
- Plasmacytoma
- Chondrosarcoma
- GCT

- dural ectasia (NF, Marfan’s, Ehlers-Danlos)
- syrinx
- spinal canal tumor
- Congenital (achondroplasia, mucopolysacchar, OI)
- Acromegaly

- RA
- Paget’s
- AS
- Trauma
- IBD
- Osteomalacia

RA
HPT
osteomyelitis
weightlifting
trauma
scleroderma

Diffuse
----Dwarfism
----OI
----Morquio’s
----epiphyseal dysplasia
----Cushing’s

Solitary or multifocal
EG
infection
trauma
mets, myeloma
lymphoma, leukemia
SCD
osteonecrosis

6 Ds

Dense subchondral bone (sclerosis)
Degeneration (attempted repair)
Destruction (margins may appear surgical)
Deformity
Debris (loose bodies)
Dislocation (nontraumatic)

-Pyknodysostosis
-Osteogenesis Imperfecta
-Rickets in healing
-Kinky Hair Syndrome
-Cleidocranial Dysostosis
-Hypothyroidism
-Otopalatodigital syndrome
-Pachydermoperiostosis
-Primary Acro-osteolysis (Hajdu-Cheney)
-Syndrome of Down
-Idiopathic (can be normal, esp.<6 mo.)

Psoriatic Arthritis
Osteoarthritis
Erosive osteoarthritis
Multicentr reticulohistiocytosis

Juvenile Rheumatoid Arthritis
Infectious arthritis
Reiter’s syndrome
Psoriatic Arthritis

DS6

Diabetes (insensitivity to pain)
Syphilis (Tabes Dorsalis)
Steroids
Spinal cord injury
Spina bifida
Syringomyelia
Scleroderma

BOOST

Brodie’s Abscess
Osteoblastoma
Osteoid osteoma
Stress fracture
Tuberculosis

Paget’s disease
Fibrous Dysplasia
Rickets
OI, Osteomalacia
Achondroplasia
Cleidocranial dysplasia
Hyperparathyroidism, Hurler’s

"OH My"

Osteopetrosis
Hyperparathyroidism
Myelofibrosis

Myeloma / Metastases
EG / Ewing’s
Lymphoma / Leukemia
Trauma (fx)/TB (infection)

NO MAAM

Neurofibromatosis (NF)
Osteogenesis Imperfecta (OI)
Marfan’s syndrome
Achondroplasia (dwarf)
Acromegaly
Mucopolysaccharidosis

"5B's Lick Pollen"

Bronchogenic (carcinoid)
Bladder
Breast
Brain (medulloblastoma, GBM)
Bowel (mucinous, carcinoid)
Lymphoma
Prostate Ca

-Fibrous dysplasia
-Engelmann’s (kids, cort thickening midshaft long bones inv periost & endost surf)
-Von Buchem’s disease (adults)
-Paget’s disease, -Pyknodysostosis
-Meningioma
-Osteopetrosis

Myxedema,
Acromegaly
Dilantin
Callus
Obesity
Peripheral edema

RA
Trauma
Down’s'
Morquio’'s

Idiopathic
PseudoHPT
PseudopseudoHPT
Turner's
Basal cell nevus syndr (mandibular cysts, dural Ca++)

- Infection
- Trauma
- PVNS (erosions, preserved jt space)
- Synovial osteochondromatosis
- AVN

Villous or lobulated masses
T1 - INT to HI
T2 - INT to HI
Effusion
Capsulosynovial thickening

Well defined rounded masses
T1 - LO
T2 - LO
Effusion
Capsulosynovial thickening

Villous or lobulated masses
T1 - HI
T2 - LO
Effusion
Capsulosynovial thickening

Common
- Osteoid osteoma
- Bone infarct
- Osteochonditis dissecans
- AVN
Uncommon
- Brodie's abscess
- EG
- Melanoma mets

Neurofibroma
Sarcoidosis
Acute hematoma

Lipoma
Hematoma
Well-diff liposarcoma
Myxoid liposarc or myxosarc

Cyst
Ganglion
Lymphocele
Hygroma
Seroma

Neurilemmoma or neurofibroma
Hemangioma
Abscess
Solid malignancy (sarc or carci)
Hemorrhagic mass

* tibial plateau fracture
* ACL avulsion fracture
* patellar dislocation w/ osteochondral injury

Psoriatic Arthritis
Osteoarthritis
Erosive osteoarthritis
Multicentric reticulohistiocytosis

Juvenile Rheumatoid Arthritis
Infectious arthritis
Reiter’s syndrome
Psoriatic Arthritis