Category Archives: Bone

Langerhans Cell Histiocytosis

Langerhans Cell Histiocytosis

Eosinophilic Granuloma

Clinical presentation:

- boys in flat or long bones in meta or diaphysis

Types of Langerhans Cell Histiocytosis:

- solitary or multiple bone lesion and other organs (skin, bone, liver, spleen)

Gross appearance:

- sharply circumscribed

Histology:

- Langerhans cells (polygonal cells with eosinophilic cytoplasm, oval nuclei with longitudinal grooves resembling coffee beans), eosinophils, giant cells, neutrophils, foam cells, lymphocytes, fibrosis, necrosis, mitoses

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Solitary Bone Cyst

Solitary Bone Cyst

Also known as Unicameral bone cyst.

Clinical presentation:

- boys in upper humerus or femur

Gross appearance:

- straw, blood tinged fluid

Histology:

- fibroblasts, blood vessels, hemosiderin

Treatment:

- curretage and replacement with bone chips

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Aneurysmal Bone Cyst

Aneurysmal Bone Cyst

Clinical presentation

- kids, metaphysis and epiphysis

Gross appearance

- lytic lesion with periosteal reaction

- cysts filled with blood, septae (contain fibroblasts, giant cells, blood vessels)

Differential diagnosis

- telangiectatic osteosarcoma, giant cell tumour of bone, giant cell reparative granuloma (if in jaw)

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Chondromyxoid Fibroma

Chondromyxoid Fibroma

Clinical presentation

- young adult at metaphysis, long bones and small bones of the feet

Gross appearance

- small, cartilaginous

Histology

- low power → lobulated appearance due to hypocellular chondroid lacunae, myxoid (stellate shape with atypia) foci and adjacent cellular foci and giant cells at periphery, much atypia

Prognosis

- benign, but may have local recurrence

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Osteochondroma

Osteochondroma

Clinical presentation

- exostoses, young males at metaphyses

Gross appearance

- sessile or pedunculated

Histology

- fibrous cap (continuous with perichondrium),

- cartilage (endochondral ossification at interface),

- bone

Can get secondary chondrosarcoma

Differential diagnosis

- secondary chondrosarcoma, parosteal osteosarcoma (spindle cells between trabeculae)

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Chordoma

Chordoma

Location:

- sacral, coccygeal

- sphenooccipital

- cervical (chondroid chordoma)

Gross appearance

- myxoid-blue and hemorrhagic

Histology

- myxoid matrix with cords of small round cells with vacuolated cytoplasm, fibrous strands separating into tumour cells into lobules or cords

- physalipherous (bubbly) cells

Chordoma variants:

Chondroid chordoma → chondroid differentiation, better prognosis (cervical)

Dedifferentiated chordoma → differentiation into high grade spindle lesion

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Multiple Myeloma

Multiple Myeloma

Plasmacytoma

Clinical presentation

- older patients, bone pain and fracture

▪ widespread skeletal lytic lesions

▪ hepatosplenomegaly

▪ hypercalcemia

▪ primary amyloidosis (AL type) and renal insufficiency due to toxicity of light chains Bence Jones proteins

Gross appearance

- lytic lesions in diaphysis of the skull and long bones

Histology

- plasma cell infiltrate withprominent nucleoli, perinuclear hof (Golgi)

- Russell bodies (cytoplasmic rods), Dutcher bodies (intranuclear rods)

Special studies:

serum: monoclonal IgG in serum (monoclonal spike in serum electrophoresis)

blood: peripheral smear→rouleaux formation

Immunohistochemistry

- CD138+, light chain restriction

Differential diagnosis

-chronic osteomyelitis (will see other inflammatory cells and vascularity)

“osteosclerotic myeloma” –> poeMs:

poeMs

polyneuropathy, organomegaly, endocrinopathy, monoclonal IgM gammopathy and skin lesions

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Giant Cell Reparative Granuloma

Giant Cell Reparative Granuloma

Clinical presentation

- Giant cell lesion primarily of jaw

Microscopy

- giant cells and small oval and spindly mononuclear cells, capillaries, hemorrhage, hemosiderin, reactive bone with osteoblastic rimming

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Brown Tumor of Hyperparathyroidism

Brown Tumor of Hyperparathyroidism

Clinical presentation

- forms in the setting of secondary hyperparathyroidism

1. parathyroid tumor causing hyperparathyroidism

2. chronic renal faiulre resulting in high levels of PO4 and low levels of Ca++

Location

- phalanges, spine, clavicle, skull

Gross appearance

- large lytic, brown (due to hemorrhage)

Microscopy

- giant cells with hemorrhage, hemosiderin, microfractures, ingrowth of vascularized fibrous tissue with fibroblastic stromal cells

Differential diagnosis

- giant cell tumor (more uniformly distributed giant cells, no interstitial hemorrhage, no fibroblastic stromal cells), giant cell reparative granuloma

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Malignant Giant Cell Tumors

Malignant Giant Cell Tumors

Clinical presentation

- benign giant cell tumor juxtaposed

Microscopy

- looks like MFH, osteosarcoma or chondrosarcoma

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