June 2007 Tumor Unknown Conference

Case 1

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

ago

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

ABC

Histology Cavernous spaces filled with blood, lacking

endothelial lining Fibroblastic cells, multinucleated giant cells

and thin strands of bone

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

Case 2

T.K. - 18 year old male with asymptomatic left ankle swelling for

several months

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

ABC

Histology Cavernous spaces filled with blood, lacking

endothelial lining Fibroblastic cells, multinucleated giant cells

and thin strands of bone

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

Case 3

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

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

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

Histology Thin fibrous membrane lining cyst Few macrophages, giant cells, leukocytes

and slivers of bone and osteoid

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

Unicameral Bone Cyst

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

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

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

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

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

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

Liposarcoma

Treatment 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

Liposarcoma

Case 5

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

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

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

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

Case 6

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

ago

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

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

Chondroblastoma

Gross 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

Chondroblastoma

DDX 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

Chondroblastoma

Case 7

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

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

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

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

Case 8

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

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

Case 9

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

bronchitis

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

Case 10

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

weeks

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

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

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%