Benign Cystic Lesions

Question 1

Mnemonic for ddx of benign cystic bone lesions

Answer 1

FEGNOMASHIC
Fibrous dysplasia
Enchondroma, Eosinophilic granuloma (EG)
Giant cell tumor (GCT)
Nonossifying fibroma (NOF)
Osteoblastoma
Mets, Myeloma
Aneurysmal Bone Cyst (ABC)
Solitary Bone Cyst (aka simple or unicameral bone cyst)
Hyperparathyroidism (Brown Tumor)
Infection
Chondroblastoma
Chondromyxoid Fibroma

Question 2

Fibrous Dysplasia

Answer 2

No periosteal reaction; if in tibia, mention adamantinoma

Question 3

Enchondroma

Answer 3

Must have calcification, except in phalanges; no periostitis

Question 4

Eosinophilic Granuloma

Answer 4

Must be under 30 yo

Question 5

Giant Cell Tumor

Answer 5

1) Epiphyses must be closed
2) Must be epiphyseal and abut the articular surface
3) Eccentric
4) Well-defined but nonsclerotic border

Question 6

Nonossifying Fibroma

Answer 6

Must be under 30; no periostitis

Question 7

Osteoblastoma

Answer 7

Mentioned whenever ABC is mentioned, even if over 30

Question 8

Mets and Myeloma

Answer 8

Must be over 40

Question 9

Aneurysmal Bone Cyst

Answer 9

Must be under 30; expansile

Question 10

Solitary Bone Cyst

Answer 10

Must be centrally located; under 30 yo

Question 11

Hyperparathyroidism (Brown tumor)

Answer 11

Must have other evidence of hyperparathyroidism

Question 12

Infection

Answer 12

If adjacent to joint, must involve the joint (weak)

Question 13

Chondroblastoma

Answer 13

Must be under 30; epiphyseal

Question 14

Chondromyxoid Fibroma

Answer 14

Mention when considering NOF

Question 15

Less than 30 yo (5)

Answer 15

EG
ABC
NOF
Chondroblastoma
Solitary Bone Cyst 
(CANES)

Question 16

No Periostitis or Pain (4)

Answer 16

FENS
Fibrous dysplasia
Enchondroma
NOF
Solitary Bone cyst

Question 17

Epiphyseal (5)

Answer 17

Chondroblastoma
Infection
GCT
Geode
(EG and ABC are optional)

Question 18

Multiple benign cystic lesions (6)

Answer 18

FEEMHI
Fibrous Dysplasia
EG
Enchondroma
Mets and Myeloma
Hyperparathyroidism
Infection