Osteochondroma is one of the most common benign bone tumors. It originates from the growth plate and continues growing during development, stopping at maturity. It is made up of a bony base with a pedunculated stalk containing fatty marrow and a cartilaginous cap. Solitary osteochondromas usually arise from large bones like the knee, femur, and humerus. Multiple hereditary osteochondromas present with multiple lesions and are inherited. Malignant conversion of a solitary osteochondroma can occur in adults but is extremely rare.

1. Volume 4
Benign Chondroid Tumors
Enchondroma---------------------------Case 120 & 548-567
Multiple enchondromatosis-----------Case 568-583
Maffucci’s syndrome------------------Case 584-586
Periosteal chondroma------------------Case 121 & 587-607
Osteochondroma-----------------------Case 122 & 608-624
Multiple hereditary exostosis---------Case 625-631
Chondroblastoma-----------------------Case 123 & 632-646
Chondromyxoid fibroma--------------Case 124 & 647-651

2. Chondroid
forming Tumors

3. Enchondroma

4. Enchondroma
The enchondroma is one of the most common benign tumors seen
in the skeletal system. It is centrally located and in 50% of the cases
will be found in small tubular bones of hands and feet where it
arises as a hamartomatous process and frequently remains un-
diagnosed throughout the life of the patient until which time as
they develop a pathologic fracture thru the lesion. The lesions
have a typical geographic pattern with sharp margination and
frequently demonstrate matrix calcification, especially as the
patient ages. In the hand or foot, the lesions frequently cause
marked thinning of the surrounding cortex and dilatation of the
bone, whereas with enchondromas found in larger bones, there
is minimal evidence of cortical invasion and little if any evidence
of cortical thinning or dilatation. It is rare for an enchondroma to
convert into a chondosarcoma in the hand or foot, but in larger
bones such as the femur or pelvis a primary enchondroma can

5. convert very gradually into a low grade chondrosarcoma. The
incidence of conversion is less than 5% of cases and almost always
in adults.
In most cases, the enchondroma will be discovered as an
incidental finding, because it is asymptomatic and non-disabling.
There is no particular need to biopsy or bone graft the lesion unless
the patient develops an interest in a specific sport or occupational
activity that would put him at risk for fracture. If an acute
fracture occurs, it is best to wait until the fracture heals and then
consider the patient for a bone grafting procedure at a later date.

6. CLASSIC
Case #120
38 year female
enchondroma
distal femur

7. Bone scan

8. Coronal T-1 MRI
tumor

9. Coronal T-2 MRI
tumor

10. tumor
Axial T-2 MRI

11. Tumor seen thru cortical window

12. Tumor curettement

13. tumor
Photomic

14. Closer up

15. High power

16. Curettement completed and ready for cement

17. cement
Cementation completed

18. Post op x-ray
tumor cavity filled
with radiolucent
cement

19. Case #548
periosteal
chondroma
57 year female
enchondroma entire
femur
Smaller periosteal
chondroma proximal
and posterior femur

20. Biopsy photomic

21. Post op x-ray
following removal of
periosteal portion

22. 8 year followup with
placement of a long
stem THA for stress
pain symptoms

23. Case #549
48 year female
enchondroma femur

24. Bone scan

25. Case #550
59 year female
enchondroma
distal femur

26. Case #550.1
Enchondroma distal femur in a 60 year male

27. Bone scan

28. Cor T-1 Cor T-2
Cor Gad

29. Sag T-1 Sag T-2

30. Axial Gad
Axial T-2

31. Case #551
62 year male
enchondroma
proximal humerus

32. Coronal T-1 MRI

33. CT scan

34. Curettement specimen

35. Low power photomic

36. Case #552
degenerative
arthritis
70 year male with enchondroma proximal humerus

37. Coronal T-1 MRI

38. Sagittal T-2 MRI

39. Case #553
58 year female
enchondroma
proximal humerus

40. Case #554
42 year female
enchondroma tumor
proximal humerus

41. Case #554.1 Enchondroma and ganglion cyst
47 year male with shoulder pain for 6 months

42. ganglion
enchondroma cyst
Coronal T-2 MRI

43. Sagittal T-2 enchondroma Sagittal T-2 ganglion

44. ganglion
Two different T-2 axial cuts showing the enchondroma
and the right cut shows the ganglion

45. Case #555
55 year male
enchondroma
tibia

46. Bone scan

47. Coronal T-1 MRI

48. Coronal T-2 MRI
tumor

49. Biopsy photomic

50. Case #556
55 year male with
enchondroma tibia

51. Lateral view

52. Axial T-1 MRI

53. tumor
Axial T-2 MRI

54. Biopsy photomic

55. Case #557
40 year female with enchondroma fibula

56. Bone scan

57. Sagittal T-1 MRI

58. Axial T-1 MRI

59. Case #558
22 year male with enchondroma proximal phalanx

60. Biopsy photomic

61. Case #559
Periosteal chondroma
enchondroma
33 year female with periosteal chondroma and
enchondroma in same ray

62. Oblique view

63. Case #560
Pathologic fracture enchondroma proximal phalanx thumb
29 year male

64. Case #561
23 yr male with path fracture thru enchondroma thumb

65. Case #562
31 year female with enchondroma great toe

66. Amputation
specimen

67. Photomic

68. Case #564
11 yr boy with enchondroma lst metatarsal

69. Case #565
26 year male with enchondroma 5th metatarsal

70. Case #566
17 year male with enchondroma os calcis

71. Os calcis view

72. Case #567
28 year female
enchondroma scapula

73. Multiple
Enchondromatosi
s
Ollier’s Disease

74. Multiple Enchondromatosis (Ollier’s)
Multiple enchondromatosis or Ollier’s disease, is a rare non-
familial cartilagenous dysplasia that is typically seen on one half
of the body and appears similar to fibrous dysplasia. Extensive
disease of the metaphyseal areas of long bone can result in bowing
and shortening. In the case of the femur a major bowing is seen
distally compared to the proximal bowing seen in fibrous dysplasia.
The cortical thinning and epiphyseal involvement seen Ollier’s
disease is rarely seen in solitary enchondromas. The chance for
malignant conversion to a low grade chondrosarcoma in adult life
is only about 25%.

75. CLASSIC
Case #568
3 year male with multiple enchondromatosis

76. Extremities

77. Macro section

78. Photomic

79. Case #569
6 year male
Ollier’s disease

80. Same patient

81. Case #570
4.5 year male
Ollier’s tibia

82. Case #571
71 year female with Ollier’s left lower extremity

83. Lateral view of knee

84. Photomic

85. Failure following
resurfacing TKA
because of loosening

86. Post op x-ray with constrained
TKA

87. X-ray of cemented
stem distal femoral
resection prosthesis

88. Case #572
15 year female
Ollier’s disease

89. AP close up knee

90. Forearm disease

91. Case #573
18 year male
Ollier’s pelvis
and ribs

92. Case #574
2 year male
Ollier’s lower
extremity

93. Case #575
28 year male
Ollier’s upper
extremity

94. Multiple sites in radial half of hand

95. AP x-ray

96. Case #576
19 year male
Ollier’s femur

97. Case #577
22 year male with Ollier’s of the hand

98. tumor
Macro section of amputation specimen

99. tumor
Close up view of macro section

100. Case #578
40 year female with Ollier’s of the hand

101. Case #579
10 year male
Ollier’s hand

102. Case #580
30 year female
Ollier’s hand

103. Case #581
3 year male
Ollier’s hand

104. Case #582
19 year male
Ollier’s feet

105. Case #583
5 year female with Ollier’s of hand ready for surgery

106. X-ray of both hands

107. Photo of deformed feet after hand surgery

108. Close up of deformed foot

109. Multiple Enchondromatosis
Plus
Soft tissue
Hemangiomatosis
Maffucci’ Disease

110. Maffucci’s Syndrome
Patients with multiple enchondromatosis or Ollier’s disease will on
occasion develop soft tissue hemangiomatosis in the same areas
as the enchondromatosis is seen. This combination of both a bony
cartilaginous and a soft tissue angiomatosis is known as Maffucci’s
syndrome. The clinical appearance of the multiple enchondromatosis
is the same as Ollier’s disease but with a higher potential for a
malignant conversion to a low grade chondrosarcoma in adult life.

111. CLASSIC
Case #584
33 year male
Maffucci’s disease

112. X-ray tibias

113. phleboliths
X-ray forearm

114. Hand x-ray

115. Hand amputation specimen

116. Macrosection thru large enchondroma

117. Photomic of enchondroma

118. Case #585
36 year female with
Muffucci’s syndrome

119. Lateral view showing
phleboliths

120. Opposite femur

121. Lateral view with
phleboliths

122. hemangioma
enchondroma
Gross specimen

123. Case #586
25 year female with Muffucci’s syndrome hands

124. Periosteal
Chondroma

125. Periosteal Chondroma
The periosteal chondroma has the same basic pathology as the
enchondroma except that it occurs on the surface of a tubular
bone. It can occur as a hamartomatous process in growing patients
but as with enchondroma it is usually asymptomatic and growth
stops at bone maturity. The lesions are found in large bones, such
as the humerus and femur, and in the small bones of the hand and
foot. Radiographically one sees slight erosion into the adjacent
cortex but the lesion will not penetrate into the medullary canal.
There will be a sclerotic response at the base that extends around
the periphery of the lesion taking on the appearance of a blister
on the surface of the bone with matrix calcification seen mainly
at the periphery but found also in the central area. The lesions
usually stop growing before they reach the upper limit of 3-4 cm
in diameter. If growth continues beyond this, one must strongly
consider the possibility of a peripheral surface type chondrosarcoma

126. that would continue to grow after bone maturity.
Periosteal sarcoma is a similar chondroid lesion found typically
on large bones. It demonstrates a more aggressive pattern,
permeation into surrounding cortical structures and a more
aggressive histology with some osteoid formation. Osteo-
chondroma also has a similar appearance but would demonstrate
a more mature bony base on which a cap of cartilage is typically
seen. In the case of the periosteal chondroma, the cartilage
extends down into the depths of the tumor.
Treatment consists of a simple resection without disturbing
the subadjacent cortex so that bone grafting or internal fixation
devices are not necessary. The recurrence rate is very low after
maturity.

127. CLASSIC
Case #121
17 year female
periosteal chondroma
distal femur

128. Bone scan

129. CT scan

130. Axial proton density MRI

131. Sagittal proton density MRI

132. Sagittal T-2 MRI

133. Photomic

134. Case #587
42 year male with
combined periosteal
chondroma and
enchondroma next to
each other in femur

135. enchondroma
Bone scan
periosteal chondroma

136. enchondroma
periosteal chondroma
Sagittal CT scan

137. Axial CT scan at level of enchondroma

138. periosteal
chondroma
enchondroma
CT scan

139. Coronal T-1 MRI
enchondroma

140. Axial T-1 MRI

141. Case #588
22 year male
periosteal chondroma
femur

142. Case #589
16 year male
periosteal chondroma
distal femur

143. AP view

144. Case #590
12 year female
periosteal chondroma
proximal femur

145. Frog leg lateral

146. Case #592
11 year female
periosteal chondroma
proximal tibia

147. Another view

148. CTscan

149. Axial proton density MRI

150. Photomic

151. Case #593
19 year female with periosteal chondroma tibia

152. Case #594
26 year male
periosteal chondroma
proximal humerus
tumor

153. CT scan

154. small enchondroma
Coronal T-1 MRI
tumor

155. Photomic

156. Case #595
46 year female with periosteal chondroma humerus

157. CT scan

158. Another CT cut

159. Coronal T-1 MRI

160. Coronal T-2 MRI

161. Photomic

162. Case #595.1 Periosteal chondroma
17 year old female with
slight pain right shoulder
for 1 year

163. Sag T-1 T-2 Gad

164. Axial T-1 T-2
Gad

165. Case #596
14 year male
periosteal chondroma
proximal humerus

166. AP view

167. Case #598
62 year male with periosteal chondroma thumb

168. Axial T-1 MRI

169. Coronal proton density MRI

170. T-2 MRI

171. Photomic

172. Case #599
8 year female with periosteal chondroma 4th metacarpal

173. Case #600
25 year female with periosteal chondroma 3rd metatarsal

174. Case #601
26 year male with periosteal chondroma ring finger

175. Case #602
54 year male with periosteal chondroma 5th metatarsal

176. Case #603
18 year male
periosteal chondroma
3rd toe

177. Case #604
33 year male with soft tissue chondroma finger

178. Lateral x-ray

179. Oblique view

180. Surgical excision

181. Photomic

182. Case #605
19 year male
periosteal chondroma
C-2

183. Bone scan

184. CT scan

185. Case #606
38 year male with periosteal chondroma ischium

186. Case #607
6l year female with periosteal chondroma clavicle

187. Osteochondroma

188. Osteochondroma
The solitaty osteochondroma or exostosis is one of the most
common benign bone tumors seen in the skeleton. As in the
enchondroma, this condition is developmental, or hamartomatous
in nature arising from the outer edge of the growth plate and
growing down the metaphyseal side where it tends to point away
from the adjacent joint. Because it originates from the growth plate,
it continues to grow during the growing years of the patient and
then stops at maturity. It is made up of a bony base with a pedunc-
ulated stock with fatty marrow extending up inside the stock that
has a cartilagenous cap giving it the appearance of a cauliflower.
Histologically, the cap has features of a normal growth plate if a
biopsy is performed during the growing years. Most of these lesions
arise from large bones, especially about the knee joint, proximal
femur, and proximal humerus. In the proximal humerus, the
osteochondroma is usually sessile-based without a typical pedunc-

189. ulated stock and is frequently misdiagnosed for that reason.
Multiple hereditary exostosis presents with multiple lesions through-
out the skeletal system and is considered to be an autosomal
dominant disorder, being one-tenth as common as the solitary
osteochondroma which is not inherited.
The conversion of a solitary osteochondoma to a chondro-
sarcoma can only occur in the adult. It is an extremely rare event
compared to the 1% chance of a malignant conversion in multiple
hereditary exostosis. It is the cartilaginous cap that converts into a
low grade secondary type of peripheral chondrosarcoma with an
excellent prognosis for survival compared to a central chondro-
sarcoma. These malignant conversions usually arise from large
osteochondromas seen in more proximal locations, such as around
the hip or pelvis. Because osteochondromata are usually without
symptoms, surgical treatment is frequently unnecessary unless the
lesions create mechanical problems such as around the knee joint

190. where larger lesions can interfere with normal ambulation.
Sometimes, a large proximal lesion with a cartilage cap exceeding
2 cm should be prophylactically resected in order to avoid a
possible chondrosarcoma. When removing an osteochondroma, it
is necessary only to remove the complete cartilaginous cap,
leaving most of the bony base intact to avoid a facture.

191. CLASSIC
Case #122
25 year male
osteochondroma
tibia

192. Lateral view

193. cartilage cap
fatty marrow
Sagittal T-1 MRI

194. cartilage cap
fatty marrow
Macro section

195. Case #608
17 year male with osteochondroma humerus

196. marrow
Axial T-1 MRI
cap

197. marrow
Sagittal T-1
MRI

198. cap
Coronal T-2 MRI

199. cap
Macro section

200. Case #609
30 year male
sessile based
osteochondroma
humerus
Coronal T-1 MRI

201. Coronal proton density MRI
cap

202. cap
Axial T-1 MRI

203. cap
fatty marrow
Axial T-2 MRI

204. Case #610
14 year male with sessile based osteochondroma humerus

205. Bone scan

206. Coronal T-1 MRI

207. Cut surgical
specimen
cap

208. cartilage cap
Photomic

209. Case #611
10 year male
sessile based
osteochondroma
proximal humerus

210. Lateral view

211. Case #612
25 year male
osteochondoma
scapula

212. Scapular view

213. cartilage cap
Resected specimen

214. Case #613
32 year male with osteochondroma proximal femur

215. Frog leg lateral

216. CT scan

217. Case #614
12 year female
osteochondroma
proximal femur

218. Case #615
15 year male
osteochondroma
distal femur

219. cap
Cut specimen in path lab

220. cartilage cap
Photomic

221. Case #616
23 year male with osteochondroma distal femur

222. cap
Cut specimen in path lab

223. cartilage cap
Photomic

224. Case #617
26 year male with osteochondroma proximal fibula

225. Lateral view

226. Case #618
18 year male with sessile based osteochondroma tibia

227. Case #619
11 year male
sessile based
osteochondroma
distal tibia

228. Case #620
38 year male
osteochondroma
L-5

229. Lateral view

230. Bone scan

231. CT scan

232. cap
Coronal T-2 MRI

233. Case #621
6 year male with osteochondroma C-6 spinous process

234. CT scan

235. Case #621
26 year male
osteochondroma
ilium

236. cap
Cut specimen in path lab

237. Case #621.1
22 year female with painless lump right iliac crest for years

238. Axial T-1 Gad

239. Cor T-2 Sag T-2

240. Case #623
31 year female with osteochondroma ant 3rd rib

241. Case #624
16 year male subungual exostosis

242. AP x-ray

243. Multiple Hereditary
Exostosis

244. CLASSIC Case #625
15 year male with multiple hereditary exostoses

245. Tibia and fibula

246. Lateral view

247. Case #625.1 Multiple hereditary exostoses
50 yr old female with short stature and R hip pain for years

248. AP and lateral of right hip

249. AP and lat tibia

250. Proximal humeral x-rays

251. AP and lateral of femur

252. Lateral ankle
Oblique foot

253. Case #626
13 year female
multiple exostoses
forearm

254. Distal femur

255. Case #627
20 year male
multiple exostoses
knee

256. Lateral view

257. Case #628
15 year male with multiple exostoses hips

258. Case #629
26 year female with multiple exostoses thorax & arms

259. Case #630
31 year male
multiple exostoses
scapula & humerus

260. Scapular view

261. CT scan

262. Case #631
26 year male
multiple exostoses
leg

263. Chondroblastoma

264. Chondroblastoma
The chondroblastoma is a benign, cartilage-forming tumor seen
in the metaepiphyseal area of bone in children and young adults.
The histologic appearance is typical of a giant cell tumor in young
adults. The chondroblastoma is one fifth as common as the giant
cell tumor and the majority of cases will occur during the second
decade of life. It is rare to find the giant cell tumor in patients
under the age of 13 years. The most common location for the
chondroblastoma is in the epiphysis of the distal femur, proximal
tibia, and proximal humerus. These lesions are usually located
near a joint and are quite painful because of a secondary inflamm-
atory synovitis of the adjacent joint that can masquerade as a
pyarthrosis. It is not unusual to find an aneurysmal bone cyst
associated with the chondroblastoma, similar to the situation seen
with giant cell tumors. Histologically, one sees round polyhedral-
shaped stromal cells located in clear cytoplasmic halos that gives

265. the appearance of chicken wire under the microscope. Giant cells
are frequently associated with the chondroid tissue that gives the
appearance of a giant cell tumor. It is very rare for a chondro-
blastoma to convert to a malignant tumor, however, as in the case
of giant cell tumor, they can metastasize to the lung and still
carry an excellent prognosis for survival.
Treatment consists of a simple curettement of the lesion
followed by packing the defect with either bone graft or bone
cement. There is a relatively low (10%) recurrence rate.

266. CLASSIC Case #123
12 year female with chondroblastoma proximal tibia

267. Coronal post gad MRI

268. Sagittal T-2 MRI

269. Photomic

270. Case #632
26 year male with chondroblastoma prox tibia

271. Lateral view

272. Sagittal T-1 MRI

273. Sagittal T-2 MRI

274. Photomic

275. Case #632.1 Chondroblastoma pseudotumor (geode)
52 yr female with pain in knee for 1 yr

276. Cor T-1 T-2

277. Axial T-2
Sag T-1

278. Case #633
21 year female with chondroblastoma prox tibia

279. Case #634
16 year male with chondroblastoma distal femur

280. Lateral view

281. Coronal proton density MRI

282. Sagittal proton density MRI

283. Axial proton density MRI

284. Curettement of tumor
from window in
intercondylar notch
tumor

285. Photomic

286. Higher power

287. Case #635
18 year male
chondroblastoma
distal femur

288. CT scan

289. Photomic

290. Case #636
20 year male with chondroblastoma & ABC prox femur

291. tumor
Axial T-2 MRI

292. Coronal T-2 MRI
tumor
edema

293. Photomic

294. Post op x-ray with
cement & DHS

295. Case #637
12 year female with chondroblastoma prox femoral epiphysis

296. CT scan

297. Another CT cut

298. cartilage
giant cells
Photomic

299. Case #638
13 year female with chondroblastoma prox fem epiphysis

300. Case #639
15 year male with chondroblastoma prox humerus

301. CT scan

302. Axial T-1 MRI

303. Coronal T-2 MRI

304. tumor
Macro section

305. Photomic

306. Photomic with giant cells

307. Case #640
15 year male with chondroblastoma proximal humerus

308. Coronal T-1 MRI

309. tumor
Coronal T-2 MRI

310. Photomic with giant cells

311. Another photomic

312. Case #641
24 year female
chondroblastoma
pelvis

313. CT scan

314. Another CT cut

315. Photomic

316. Case #642 CT scan
21 year male with chondroblastoma ilium

317. Another CT cut

318. tumor
T-2 MRI

319. Case #643
43 year female with chondroblastoma distal humerus

320. CT scan

321. Case #644
11 year male with chondroblastoma lateral malleolus

322. Sagittal T-1 MRI

323. Axial T-2 MRI

324. Photomic

325. Case #645
12 year female
chondroblastoma
distal fibula

326. Case #646
18 year male with chondroblastoma talus

327. Lateral view

328. Chondromyxoid
Fibroma

329. Chondromyxoid Fibroma
Chondromyxoid fibroma is a very rare solitary benign tumor seen
in bone. It occurs typically in the second or third decade of life and
affects men more than women. By far the more common location
for this lesion is in the proximal tibial metaphysis, followed
second by the distal femur and the first ray of the foot. This lesion
is slow growing and is associated with mild symptoms of pain.
Radiographically, there is a lytic lesion of bone with a soap-
bubbly appearance secondary to the thin sclerotic peripheral
margin giving it a pseudoloculated appearance similar to that of
a solitary bone cyst. The adjacent cortex is frequently thinned out
and slightly dilated, similar to the pattern that is seen in fibrous
dysplasia. Histologically, there will be evidence of benign fibrous
tissue with large areas of myxomatous degeneration with reactive
macrophage activity seen at the periphery of the lesion that could
suggest the diagnosis of a chondrosarcoma.

330. Treatment for this lesion consists of a simple curettement and bone
grafting. The fairly high recurrence rate of 25% can be reduced by
a more aggressive, marginal resection of the tumor. Occasionally,
this lesion can convert into a chondrosarcoma.

331. CLASSIC
Case #124
11 year male
chondromyxoid fibroma
proximal tibia

332. Tomogram cut

333. Surgical exposure of tumor

334. Low power photomic

335. giant cells
myxoid
Higher power

336. Surgical curettement completed ready for bone graft

337. Placement of fibular strut and cancellous graft

338. Post op x-ray

339. Case # 124.1 AP and lat x-ray
50 year male with chondromyxoid fibroma proximal
tibia with 6 months of a tender tumor mass anterior tibia

340. Coronal T-1 MRI

341. Coronal PD FS MRI

342. Axial PD FS MRI

343. Axial Gad MRI

344. Case #647
12 year female with chondromyxoid fibroma tibia

345. Case #648
13 year female with chondromyxoid fibroma tibia

346. Case #649
25 year female
chondromyxoid
fibroma 1st metatarsal

347. Oblique view

348. Photomic

349. Photomic

350. Case #650
7 year female
chondromyxoid
fibroma ulna

351. Photomic

352. Case #651
25 year female with chondromyxoid fibroma rib

353. Photomic

354. Case #651.1
60 year female with chondromyxoid fibroma distal sacrum

355. Sag T-1 Sag T-2

356. Axial T-1
Axial T-2

357. Coronal T-1