bone tumors

bone tumors: general features

primary tumors: rare tumors that are outnumbered by metastases & hematopoietic tumors

most bone neoplasm develops during the first several decades of life & have a propensity for the long bones of the extremities

tumors may be asymptomatic or present with pain or slow-growing mass

risks of tumors increased by chronic injury & inflammation

osteoma

bosselated, round sessile tumors that project from the subperiosteal or endosteal surface of cortex

• composed of woven & lamellar bone

• slow growing

clinical presentation

• solitary & detected in middle age

related/associated disease

• Gardner syndrome

Gardner syndrome

a condition characterized by multiple osteomas

osteoid osteoma

benign, small (< 2.0 cm) lesions that usually involves the tibia & femur (long bones)

• nidus of osteoid & connective tissue (woven bone) surrounded by a dense sclerotic bone shell

  • nidus RADIOLUCENT on X-ray

clinical presentation

• occur in male teenagers & young adults

• pain @ night (cause by prostaglandin E₂) that is relieved by aspirin

osteoblastoma

larger lesions than osteoid osteomas (> 2 cm) that involve the posterior spine

clinical presentation

• back pain

• dull pain UNRESPONSIVE to salicylates

• does NOT induce a marked bony reaction

osteochondroma

benign outgrowth (exostosis) of bone with a cartilage cap

• develop only in bones of endochondral origin & arise from the metaphysis near the growth plate of long tubular bones → especially near the knee

• grossly seen as mushroom-shaped outgrowths

• only bone portion seen on X-ray

risk factors

• MEN affected more than women

• late adolescence & early adulthood

• may be associated with an increased risk of malignancy (5 - 20% of hereditary type)

chondroma

benign tumor of hyaline cartilage

• results from the failure of ossification

• RADIOLUCENT on X-ray

• NO PAIN

examples

• enchondroma

• Ollier disease

• Maffucci syndrome

enchondroma

benign tumor of hyaline cartilage that arise with in the medullary cavity

• usually < 3.0 cm in size

• NO PAIN

Ollier disease

enchondromatosis - benign, multiple growths of cartilage (enchondromas)

Maffucci syndrome

multiple enchondromas associated with soft tissue hemangiomas (benign lesions of blood vessels)

• increased risk of malignancy, including ovarian carcinomas & gliomas

fibrous dysplasia

localized area of disordered maturation of woven bone with fibrous tissue (fibroblasts)

• may be polyostotic or monostotic

• curvilinear bony spicules shaped like Chinese figure surrounded by fibroblasts seen on biopsy

• manifestations results from a somatic gain-of-function mutation during development in GNAS1 (gene that is also mutated in pituitary adenomas)

fibrous dysplasia - monostotic

localized area of disordered maturation of woven bone with fibrous tissue that involves the femur, tibia, ribs, humerus, etc.

• frequently asymptomatic

• occurs equally in boys & girls

fibrous dysplasia - polyostotic

localized area of disordered maturation of woven bone with fibrous tissue that involves the femur, skull, tibia, ribs, humerus, ribs, fibula, radius, ulna, mandible, & vertebrae

• may progress to crippling deformities & fractures

• manifests @ a slightly earlier age

• occurs equally in boys & girls

McCune-Albright syndrome

a condition characterized by polyostotic fibrous dysplasia in females

• precocious puberty & café au lait spots on the skin

osteosarcoma

most common primary bone cancer arises in the metaphyseal cancellous bone & lifts the periosteum → Codman triangle on X-ray & sunburst also seen X-ray

• mainly affects young males around knee area (distal femur or proximal tibia) presenting with pain & progressive swelling

• seen in older males with predisposing factors: Paget disease, bone infarcts, & prior radiation (secondary type)

• associated with

  • RB gene - retinoblastomas (white reflex in eyes)

  • TP53 - Li-Fraumeni syndrome

  • INK4a, MDM2, CDK4

clinical presentations

• large bulky tumors that often contains areas of hemorrhage & cystic degeneration

• tumor cells: very in size & shape (pleomorphic) & frequently have large hyperchromatic nuclei

  • osteoblastic type can produce bone

treatments

• chemotherapy followed by surgery

• with treatment: 5-year disease-free survival rate 60 - 70%

• < 20% 5-year survival rate with overt metastasis or recurrent disease

chondrosarcoma

second most common malignant matrix-producing tumor of bone that commonly arise in the central (intramedullary) portions of the axial skeleton, including the pelvis, shoulder & ribs

• 15% may arise from enchondroma or osteochondroma (secondary type)

clinical presentations

• occurs in males age 40 years or older

• large, bulky tumors made up of nodules of gray-while, somewhat translucent glistening tissue

• tumor cells: vary in degree of cellularity, cytologic atypia, & mitotic activity

treatment

• wide surgical excision

• 5-year survival rate: grade 1 tumors (80 - 90%) vs grade 3 tumors (43%)

  • grade > stage

Ewing sarcoma

the second most common group of bone sarcomas in children that usually arise in the diaphysis or long tubular bones, especially the femur & the flat bones of the pelvis

• primitive neuroectodermal tumor (PNET) associated with t(11;22)

• rapidly growing & arises in the medullary cavity extending to the cortex, periosteum, & soft tissue

clinical presentation

• typically occurs between ages 10 - 15

• produces “onion skin layering“ on x-ray

• composed of sheets of uniform small, round cells with scant cytoplasm

• presents as painful enlarging masses & the affected site is frequently tender, warm, & swollen

• may have systematic findings, including fever, elevated sedimentation rate, anemia, & leukocytosis which mimic infection (osteomyelitis)

treatment

• neoadjuvant chemotherapy followed by surgical excision with or without irradiation

• 5-year survival rate 75% with aggressive therapy

• scenario → give antibiotics & no improvement

giant cell tumor

uncommon benign but locally aggressive tumor that frequently arises around the knee (distal femur & proximal tibia)

clinical presentations

• usually arises in individuals in their 20s - 40s

• soap bubble appearance on X-ray

• large, red-brown tumors that frequently undergo cystic degeneration

• mostly composed of uniform oval mononuclear cells and numerous osteoclast-type giant cells with 100 or more nuclei

• neoplastic cells consist of proliferating mononuclear cells, not giant cells

treatment

• curettage, but 40% to 60% of cases recur locally

metastatic disease

most common form of skeletal malignancy, with 75% of cases in adults originating from cancers of the prostate, breast, kidney, and lung

• in children, they can originate from neuroblastoma, Wilms tumor, osteosarcoma, Ewing sarcoma, & rhabdomyosarcoma

• metastases often involve the axial skeleton, proximal femur, & humerus

• purely lytic, purely blastic (e.g. prostate), or a mix of lytic & blastic

fracture

loss of bone integrity due to mechanical injury and/or diminished bone strength

simple fracture

fracture in which the overlying skin is intact

compound fracture

fracture in which the bone communicates with the skin surface

comminuted fracture

fracture in which the bone is fragmented

displaced fracture

fracture in which the ends of the bone at the fracture side are not aligned

fracture healing

1. soft tissue callus

2. bony calllus

3. callus

soft tissue callus

hematoma (immediate), fibroblasts & capillaries

osteoclastic & osteoblastic activity (first week)

bony callus

deposits of subperiosteal trabeculae of woven bone (2 weeks)

• enchondral ossification (end of 2^nd or 3^rd week)

callus

excess of fibrous tissue, cartilage, & woven bone (3 - 6 weeks)