This document summarizes 10 tumor cases presented at a conference. Case 1 involves a 21-year-old male with an aneurysmal bone cyst in his distal ulna. Case 2 is an 18-year-old male also with an aneurysmal bone cyst, this time in his left ankle. Case 3 is a 12-year-old male with a unicameral bone cyst in his left hip.

1. June 2007
Tumor Unknown Conference

2. Case 1
C.G. - 21 year old male with a history
of curretage and bone grafting of a
distal ulnar lesion eighteen months ago

3. Aneurysmal Bone Cyst (ABC)
 Osteolytic, hyperplastic, hyperemic-hemorrhagic
lesion of unknown origin
 Epidemiology
 80% before 20 years of age, rare after 30 years old
 Most common sites: long bones LE > UE
 30% secondary lesions due to pre-existing tumor
 Radiographs
 Eccentric, expansile, lytic lesion of metaphysis
 Cortical attenuation or destruction
 Rim of reactive bone
 Fluid-Fluid levels on MRI are characteristic

4. ABC
 Histology
 Cavernous spaces filled with blood, lacking
endothelial lining
 Fibroblastic cells, multinucleated giant cells
and thin strands of bone

5. ABC
 Treatment
 Excision, curettage, and bone grafting
 Resection in case of an expendable bone.
 Other modalities include adjuvant cryo,
chemical cautery, injection of steroids
 Radiation not recommended
 Prognosis
 Local recurrence rate approx 10%, increased if
open physis

7. Case 2
T.K. - 18 year old male with
asymptomatic left ankle swelling for
several months

8. Aneurysmal Bone Cyst (ABC)
 Osteolytic, hyperplastic, hyperemic-hemorrhagic
lesion of unknown origin
 Epidemiology
 80% before 20 years of age, rare after 30 years old
 Most common sites: long bones LE > UE
 30% secondary lesions due to pre-existing tumor
 Radiographs
 Eccentric, expansile, lytic lesion of metaphysis
 Cortical attenuation or destruction
 Rim of reactive bone
 Fluid-Fluid levels on MRI are characteristic

9. ABC
 Histology
 Cavernous spaces filled with blood, lacking
endothelial lining
 Fibroblastic cells, multinucleated giant cells
and thin strands of bone

10. ABC
 Treatment
 Excision, curettage, and bone grafting
 Resection in case of an expendable bone
 Other modalities include adjuvant cryo,
chemical cautery, injection of steroids
 Radiation not recommended
 Prognosis
 Local recurrence rate approx 10%, increased if
open physis

12. Case 3
S.P. - 12 year old male with left hip
pain after a minor fall

13. Unicameral Bone Cyst
 Benign fluid filled cystic lesion of bone
of unknown cause
 Epidemiology
 5-15 years of age
 Male > Female
 Proximal humerus most common, followed
by proximal femur

14. Unicameral Bone Cyst
 Symptoms
 Asymptomatic unless fracture occurs
 Radiographs
 Central lytic lesion of metaphysis
 Attenuation and slight expansion of cortex
 Fluid filled on CT/MRI

15. Unicameral Bone Cyst
 Histology
 Thin fibrous membrane lining cyst
 Few macrophages, giant cells, leukocytes
and slivers of bone and osteoid

16. Unicameral Bone Cyst
 Treatment
 Cysts become inactive at skeletal maturity and
typically resolve without surgical intervention
 Multiple treatments including curettage and
bone grafting, steroid injections have been tried
with variable efficacy
 Fractures tend to lead to resolution of cyst
 Displaced fractures are the only absolute
surgical indication

17. Case 4
A.M. - 87 year old female with an
asymptomatic posterior thigh soft tissue
mass present for many years, the patient
reports that it has increased in size over the
past three months

18. Lipoma
 Benign tumor of mature fat
 Classification
 Superficial: (more common)
 contained within subcutis
 prevalence for back, neck, proximal limbs
 Deep: (less common)
 within muscle or intermuscular spaces
 Age
 Most frequent between 40-60 years old
 Presentation
 Slow growing asymptomatic mass

19. Lipoma
 Imaging
 Resembles normal fat on all CT and MRI images
 Histology
 Mature fat cells (lipocytes)
 Rarely small areas of hemmorrage, necrosis, calcification
 Absence of lipoblasts and pleomorphic, hyperchromatic
nuclei differentiate lipoma from liposarcoma
 Treatment
 Marginal Excision
 Local recurrence is rare

20. Liposarcoma
 Primary malignant tumor arising from fat
 15% of all soft tissue tumors
 Usually presents at 40-60 years of age
 Two main types
 Myxoid: usually low grade Stage I lesion
 Cytogenic marker: reciprocal translocation on chromosome 12
 Pleomorphic: usually high grade Stage II lesion

21. Liposarcoma
 Can be very large at presentation due to anatomic
location and deep-seated, slow-growing nature
 Also typically not painful or tender
 MRI
 Similar to other soft tissue sarcomas,
with multilobular configuration
 T1) Low intensity
 T2) Bright signal

22. Liposarcoma
 Myxoid Histology
 Sheets of lipocytes or lipoblasts interspersed in myxo-matous
amorphous matrix with low cell to matrix ratio
 Fine branching capillaries with arborization pattern,
resemble a road map
 Pleomorphic Histology
 More cellular
 Lacks plexiform capillary network
 May have large, bizarre lipoblasts with abundant
eosinophilic cytoplasm

23.  Treatment
Liposarcoma
 Preoperative adjuvant radiation therapy
 Wide surgical excision
 Treatment
 Wide local excision
 Radiotherapy may be used to control local recurrence
and lessen the risk of metastasis
 Prognosis
 Five year survival: well differentiated 85-100%,
myxoid 75-95%, round cell and pleomorphic
20-50%, dedifferentiated 30%
 Local recurrence 10% with adequate margins

24. Case 5
T.S. - 44 year old male with six month
history of an anterior shoulder mass

25. Pleomorphic Sarcoma
 Malignant soft tissue tumor of
mesechymal origin
 Epidemiology
 7000 new cases of soft tissue sarcomas
diagnosed yearly
 Lesions classified according to direction of
differentiation
 Can be caused by radiation exposure

26. Pleomorphic Sarcoma
 Symptoms
 Enlarging mass, most are large, deep and
firm at diagnosis
 Can be painless or painful
 Radiographs
 MRI is the best imaging modality

27. Pleomorphic Sarcoma
 Histology
 Dedifferentiated mesenchymal cells
 Grade of tumors determined on histology
 Treatment
 Radiation therapy
 Wide surgical excision, limb salvage if possible
 Prognosis depends on
 Tumor Grade
 Size (> 5 cm)
 Location superficial or deep to fascia

28. Case 6
D.E. - 15 year old male with left knee pain after
falling from a skateboard three weeks ago

29. Chondroblastoma
 Benign tumor composed of chondroblasts
 Epidemiology
 Male: female is 3:1
 10-20 years of age
 Localization
 Epiphysis, apophysis, or short bone
 Extension to metaphysis and even through
physeal plate.
 Proximal humerus>distal femur>proximal
tibia>proximal femur

30. Chondroblastoma
 Clinical Presentation
 Pain, usually referred to a joint
 Moderate to long duration
 Imaging
 XR: Osteolytic with smooth boarders, eccentric
 CT/MRI: Well defined boarders, fuzzy mottled
intratumoral radio densities

31.  Gross
Chondroblastoma
 Rubbery soft with sharp limits toward the
surrounding bone
 Pink to gray to tan in color
 Whitish foci or chalky granules (calcifications)
 Histo
 Highly cellular: Chondroblasts and Giant cells
 Pathognomonic: calcium in fine granules
deposited on a reticular network producing a
“chicken-wire” pattern

32.  DDX
Chondroblastoma
 Giant Cell Tumor, Clear Cell Chondrosarcoma,
Chondroma, Chronic Brodie’s abscess
 Treatment
 Stage 1, 2, and some stage 3: intralesional
excision after frozen confirmation
 Stage 3: wide intra or extraarticular segmental
resection
 Prognosis
 Local recurrence < 10% after curettage in stage
3 tumors, rare after wide resection

34. Case 7
T.L. - 49 year old male with left elbow
pain and swelling after a fall

35. Osteomyelitis
 Bone Infection
 Acute hematogenous, subacute focal disease,
and chronic types
 Epidemiology
 Most common in infants and children
 Declining incidence due to better dx/tx
 Staph aureus most common in all age groups

36. Osteomyelitis
 Symptoms
 Pain, decreased ROM, swelling, erythema,
fever, malaise, irritability
 Radiographs
 Delayed changes on imaging (2-4 weeks)
 Lytic lesion with mottled appearance usually
in metaphysis
 Periosteal elevation/reaction

37. Osteomyelitis
 Histology
 Mixed cell population
 Sequestrum: dead cortical bone
 Involucrum: new cortical bone
 Treatment
 Biopsy/culture
 Acute
 IV antibiotics ± surgical debridement
 Chronic
 IV antibiotics with surgical debridement

38. Case 8
K.M. - 13 year old female with a painful
soft tissue mass of the left anterior knee

39. Epithelioid Granulomatous Inflammation
 Chronic inflammation
 A compact collection of cells of the mononuclear
phagocyte system
 Types
 Low Turnover: Foreign body
 High Turnover: Epithelioid, hypersensitivity
 Treatment
 Marginal excision

40. Case 9
N.S. - 19 year old male with a chest wall mass
discovered on an x-ray for suspected bronchitis

41. Calcifying Fibrous Tumor of Pleura
 Very rare benign fibrous tumor of pleura
 Composed of hyalinised collagen with psam-momatous
calcification and inflammatory infiltrate
 Rare cases reported in the literature are in patients
less than 30 years old
 Imaging shows circumscribed lesion with
increased density centrally which represents
areas of calcification
 Treatment is typically excisional biopsy to rule
out sarcoma

42. Case 10
A.Z. - 70 year old female with left distal
thigh pain and swelling for several weeks

43. B-Cell Lymphoma
 Neoplasm of B-Lymphocytes
 Most common Non-Hodgkin lymphoma
 Fourth through seventh decades
 Primary lymph node disease
 Extranodal sites
 More than 50% of patients will have
extranodal involvement at diagnosis
 Primary bone lymphomas are rare
 (5% of extranodal disease)
 Most common site is the thigh

44. Large B Cell
Lymphoma of Soft Tissue
 Symptoms
 Often mild and prolonged before diagnosis
 Radiographs
 Lytic lesion with “moth eaten” appearance
 Histology
 Dense sheets of round cells
 CD-20 positive

45. Large B Cell
Lymphoma of Soft Tissue
 Treatment
 Combined chemotherapy and radiation to
bony sites
 Chemo: Cytoxan, adriamycin, vincristine,
and prednisone
 If remission is obtained by 6 cycles of chemo,
cure rates approximate 60-70%