BONY TUMORS

Lytic Lesions in Bone

1.  Malignant

  1. Primary
  2. Osteogenic sarcoma
  3. Chondrosarcoma
  4. Ewings sarcoma
  5. Multiple Myeloma
  6. Secondary
  7. Lung
  8. Breast
  9. Thyroid
  10. Kidney

2.  Benign

  1. Pseudocyts - region of relatively low stress within a bone resulting in trabecular bone formation that is not as pronounced as in higher stress areas.
  2. Simple bone cyst
  3. Osteoid osteoma
  4. Fibrous dysplasia
  5. Paget disease
  6. Neoplasms
  7. Giant cell tumor of bone
  8. Enchondroma
  9. Vascular
  10. Hemangioma
  11. Aneurysmal bone cyst
  12. Infective
  13. Brodie’s abscess
  14. Endocrine/Metabolic
  15. Brown tumor in hyperparathyroid bone disease

Benign

Simple Bone cyst

·  common, benign, fluid-containing lesion, usually occurring in the metaphysis of long bones.

·  May be due to venous obstruction and blockage of interstitial fluid drainage, in an area of rapidly growing and remodeling cancellous bone

·  Most cysts occur in the first and second decades of life, with most occurring in children aged 4-10 years.

·  found in tubular bones in 90-95% of patients. Within the long bones, most simple bone cysts are situated in the proximal metaphysis

·  Xray - fallen fragment sign

·  goal of treatment of simple bone cysts is to prevent pathologic fracture, promote cyst healing, and to avoid cyst recurrence or refracture.

·  can be treated with curettage and bone grafting, cryotherapy, intramedullary nailing, injection of methylprednisolone under image-intensifier guidance, injection of bone marrow, or a combination of the above methods.

·  mechanism of action of methylprednisolone injection is unclear. A possible theory is a reparative response to the minor injury caused by the injection process. Advantages of methylprednisolone injection include shorter operating times, less bleeding, and minimum hospital stay and rehabilitation. However, the healing rate with methylprednisolone injection has been reported as unpredictable and usually is incomplete even after multiple injections. The failure rate in weight-bearing bones has been reported to be high.

Exostosis

§  benign osteocartilaginous overgrowth

§  majority of exostoses are located on the great toe (77%), likely secondary to trauma of wearing shoes or from repeated pressure

§  xrays- typically shows a sessile or pedunculated expansion of trabecular bone with radiolucent cartilage

Subungual exostoses

Osteochondromas

§  osteocartilaginous tumors

§  congenital, originating from the physis

§  commonly involve the proximal metaphyses rather than the distal bone as with exostoses

§  Histologically, however, exostosis have a fibrocartilage cap compared to osteochondroma's hyaline cartilage cap

§  Multiple Hereditary Exostoses

o  AD

o  average age of diagnosis is 3 yrs;

o  arise from metaphyses, point away from epiphysis, and appear to extend down diaphysis during growth

o  chondrosarcoma may develop in 1-2% of patients > 21 yrs of ag

§  clinical problems include:

1.  fracture

2.  pressure of exostosis on surrounding soft tissues;

3.  neurovascular compromise;

4.  reduced bone growth

o  especially ulna - distal ulna contributes more to total bone length than does distal radius and therefore is more prone to shortening from a distal exostosis

o  options include

§  stapling of radial hemiepiphysis may improve wrist alignment as well as improving supination and pronation;

§  ulnar lengthening:

Enchondroma

§  benign cartilaginous neoplasms in bone

§  results from failure of normal endochondral ossification below growth plate and represents a dysplasia of the central growth plate;

§  if dysplastic process occurs in lateral growth plate, resulting tumor is an osteochondroma;

§  favor the tubular bones of the hand

§  50% are in the proximal phalanx, followed in frequency by the metacarpal and middle phalanx and, lastly, by the distal phalanges and carpus.Congenital cartilaginous rests are implicated in their origin, and the lesions are totally benign

§  tend to occupy the diaphyseal region in the short tubular bones and metaphyseal region in the longer bones

§  Enchondromas are metabolically active and may continue to grow and evolve throughout the patient's lifetime. Progressive calcification over a period of years is not unusual. Calcification in enchondromas is progressive.

§  Rapid growth of the lesion may also be suggestive of malignancy. Loss of calcification in a focal region suggests malignant degeneration with destruction of the underlying enchondroma by sarcomatous tissue.

§  < 2% of asymptomatic solitary enchondromas will transform to chondrosarcoma;

§  Often presents with pathological fracture

§  Xray - enchondromas appear as radiolucent, symmetric, fusiform, expansile diametaphyseal lesions that do not involve the epiphyses (at least not until growth plate fuses)

§  Treatment usually consists of curettage of the tumor through a window in the cortex, with or without cancellous bone grafting, others have used bone cement

§  Multiple enchondromas

1.  Ollier Disease

§  Nonhereditary

§  most patients have bilateral involvement, with predominance on one side;

§  Chondrosarcoma in 20-30%

2.  Maffucci Syndrome

§  rare, nonhereditary

§  manifests early in life, usually around the age of 4 or 5 years, with 25% of cases being congenital.

§  Associated with multiple hemangiomas

§  The disease appears to develop from mesodermal dysplasia early in life.

§  Chondrosarcoma risk is near 100%

3.  Metachondromatosis consists of multiple enchondromas and osteochondromas, and it is the only 1 of the 3 disorders that is hereditary

§  Management

1.  asymptomatic solitary enchondromas may be followed non operatively with serial radiographs; prognosis for benign enchondroma is excellent.

2.  if solitary or multiple enchondromas become symptomatic or begin to enlarge, they may require biopsy to r/o malignancy;

3.  - note the terrible triad: pain, increase radioisotope uptake on bone scan, & destructive changes on x-ray;

Aneurysmal bone cysts

§  eccentrically placed in the metaphysis or diaphysis

§  expansile osteolytic lesion with a thin wall, containing blood-filled cystic cavities.

§  Trauma is considered an initiating factor in the pathogenesis of some cysts in well-documented cases involving acute fracture. Local hemodynamic alterations related to venous obstruction or arteriovenous fistulae that occur after an injury are important in the pathogenesis of an aneurysmal bone cyst.

§  lucent, and resemble a subperiosteal blowout

§  curettage and bone grafting has a 20-40% recurrence rate: recurrence can be managed with more aggressive curettage or excision;

§  marginal excision or wide excision with bone grafting is preferable;

Osteoma

§  Benign tumor of membranous bone consisting of dense, compact bone

§  typically arises from skull bone

§  common tumor of the paranasal sinuses

§  Most frequently seen in the frontal and ethmoid sinuses

§  CT scan imaging shows a round homogeneous growth

§  May be external or involve the frontal sinus/intracranial – may cause proptosis

§  Multiple paranasal osteomas are found in Gardner’s syndrome

o  Variant of FAP, desmoids tumors, epidermal inclusion cysts

Osteoid Osteoma

§  classified as cortical, cancellous, or subperiosteal.

§  benign osteoblastic tumor

§  unknown aetiology

§  nidus of an osteoid osteoma consists of richly vascularized osteoblastic osteoid tissue rarely larger than 1 cm.

§  Typically the pain is worse at night, and is completely relieved by aspirin

o  Pain shown to be mediated by prostaglandins

§  Xray - area of relative sclerosis with an inner lucency

§  Treatment:

o  percutaneously ablation by using radiofrequency (RF) – treatment of choice
other modalities - thanol, laser, or thermocoagulation therapy under CT guidance

o  complete excision of the lesion and packing of the cavity with cancellous bone.

partly calcified lesion in the medulla of the distal phalanx, with no periosteal new bone formation suggestive of osteoid osteoma.

Giant cell tumor of Bone

·  occurs in adults aged 20 to 40

·  relatively uncommon tumor.

·  characterized by the presence of multinucleated giant cells

·  In most patients, giant cell tumors have an indolent course, but tumors recur locally in as many as 50% of cases.

·  Metastasis to the lungs may occur (5-10%)

·  Although called giant cell tumor, the basic proliferating cell is the background mononuclear stromal cell in which the characteristic osteoclastlike giant cells are uniformly distributed. The origin of the mononuclear cells is not fully known, but they are believed to be derived from primitive mesenchymal stem cells or cells of a histiocytic macrophage origin.

·  Osteoclastlike giant cells have an identical nuclear morphology, which is presumably formed by the fusion of mononuclear stromal cells.

·  Most giant cell tumors (60%) occur in the long bones, and almost all of the tumors are located at the articular end of the bone – commonly distal radius

·  Xray - expansile, osteolytic, radiolucent lesions without sclerotic margins and usually without a periosteal reaction.

Staging:

·  stage I:

o  benign latent giant cell tumors;

o  no local agressive activity;

·  stage II:

o  benign active GCT;

o  imaging studies demonstrate alteration of the cortical bone structure;

·  stage III:

o  locally aggressive tumors;

o  imaging studies demonstrate a lytic lesion surrounding medullary and cortical bone;

o  there may be indication of tumor penetration through the cortex into the soft tissues;

Management

·  due to proximity to articlar cartilage, excision of GCT of bone is difficult;

·  because intralesional excision of GCT tends to leave tumor cells behind, past attempts of excision had been asociatted w/ high recurrance rate (40%);

·  GCT involving the distal radius may be more agressive that GCT in other locations;

·  prior pathologic fracture should be allowed to heal before surgery is attempted;

·  Stage 1 and II –

o  intra-lesional excision is treatment of choice

o  excision is facilitated by making a large cortical window

o  high speed burr is used to complete the excision, with care taken to remove 5 mm of normal bone surrounding the lesion

o  defect is packed with bone graft or cement

o  adjunctive

§  phenol (5%), polymethacrylate, and liquid nitrogen

§  work by increasing the zone of necrosis at periphery of excision

§  cement - heat generated from the polymerization reaction may kill tumor cells 0.5 mm in cortical bone and 2 mm in cancellous bone

·  Recurrent and Stage 3

o  en bloc excision with wide margin along with appropriate reconstruction;

o  en bloc excision often involves removal of one side the joint, necessitating a major limb reconstructive procedure (often with allografts);

o  Radiotherapy – traditionally avoided because of the possibility of malignant degeneration of the tumor;

·  Metastatic disease

o  tumor is considered benign if pulmonary lesions are histologically benign;

o  pulmonary lesions may be cured with surgical resection;

Xray showing erosion

Malignant tumors

Ewing’s sarcoma

§  accounts for approximately 6 to 10% of primary malignant tumors of bone

§  rare in the hand.

§  affects males twice as often as females and of a younger age group than any other bone tumor.

§  may arise from primitive reticulum cells of marrow

§  almost always presents as a stage IIb lesion;

§  xray - cortical involvement may produce periosteal reaction, "onion skin" pattern

§  potentially the most lethal of all the bone tumors

§  generally has a poor prognosis

Osteosarcoma

§  rare tumor in the hand,

§  may arise de novo or may be secondary to a benign process.

§  Osteosarcomas in general tend to occur more frequently in irradiated bone, Paget’s disease, fibrous dysplasia of bone, giant cell tumor, solitary enchondroma, multiple enchondromatosis, and multiple osteochondromas

§  Most present at stage IIb, 10% have pulmonary mets

§  metastatic spread is the single most important prognostic factor.

§  osteosarcoma tends to have early hematogenous metastasis

§  A combination of destructive and proliferative new bone is usually present, showing a streaked texture and a characteristic sunburst pattern and a Codman triangle formed by elevation of the periosteal reaction

§  Histologically osteosarcoma has a typical spindle-shaped cell pattern.

Chondrosarcoma

§  Most have no pre-existing lesion, may occasionally be associated with osteochondromas and, to a lesser degree, with multiple enchondromatosis

§  Characteristically occur in older patients (60-80 years) in the epiphyseal area of the proximal phalanx or metacarpal.

§  clinical course is slow and metastasis is late.

§  Prognosis is good if metastasis has not occurred.