Approach to Bone Tumors😊

Approach to Bone Tumors

• No man’s land in flexor tendon → Zone 2

• Infertility workup → WHO grade 2 is most common

• BE FAN VEIN

• Patellar clunk syndrome

HLA associations

HLAs	Diseases
DQ1	• Pemphigus Vulgaris
DQ7	• BP variant
DQ2 / DQ8	• Celiac disease • Seal with DQ ()
DR2	• Good Pasteur’s (GBS) • Narcolepsy (DQB1:06:02) • Multiple sclerosis (B16, DR2) • 2nd - Good doctor () - have MS () - always sleeps ()
DR3	• Chronic active hepatitis • Dermatitis herpetiformis • SLE • Sjogren’s • T 1 DM
DR4	• Rheumatoid arthritis • Pemphigus vulgaris (DQ1, DR4)
DR5	• Hashimoto’s thyroiditis (DR3, DR5)
B27	• Ankylosing spondylitis • Reactive arthritis • Psoriatic arthritis
B35	• De Quervain's thyroiditis
B47	• CAH
B51	• Behcet’s disease
B57	• Abacavir hypersensitivity (B*57:01)

Periosteal Reaction

• Periosteal Insult: 
• Triggers new bone formation.

• Prevention: 
• The periosteum tries to contain and prevent the spread of the pathology.

• Types of Reaction:
• Slow Growing/Indolent Lesion: 
• Characterized by thick/solid periosteal reaction.
• Rapidly Growing/Aggressive Lesion: 
• Exhibits thin/lamellated periosteal reaction
• e.g., onion peel appearance

X-Ray Features of Periosteal Reaction

Features	Tumors (m/c)
Onion Peel	Ewing's Sarcoma
Sunburst/Sunray	Osteosarcoma
Codman's Triangle	Osteosarcoma
Solid/Thick	Osteomyelitis

Sites of Bone Tumors

Classification Based on Location in Bone

Classification Based on Age Group

Pulsatile Bone Tumors

• Most Pulsatile: 
• Osteosarcoma.

• Others: 
• Aneurysmal bone cyst,
• giant cell tumor,
• metastasis from kidney and thyroid.

Metastasis/Secondaries

• Most Common Malignant Bone Tumor: 
• Metastasis.
• Most Common Sources of Cancer (Ca): 
• Ca Breast > Ca Prostate > Ca Lung (Neuroblastoma in children).

• Most Common Location: 
• Spine
• Lumbar > Thoracic vertebrae.

Characteristics of Secondaries

• Breast
• Lytic >> Blastic

In vertebral metastasis involving the pedicle

• Winking owl sign is seen: One pedicle destroyed by metastasis.
• Mnemonic: Owl ne kand pedich (Pedicle)

Secondaries from Primary Bone Tumor

• Most Common Location: 
• Lungs.

• Bone to Bone Metastasis:
• Ewing's sarcoma.
• Osteosarcoma.
• Mnemonic: Osil kude povum, parannum povum

Miscellaneous Bone Tumors

• Most Common Primary Malignant Bone Tumor: 
• Multiple Myeloma > Osteosarcoma.

• Most Common Primary Non-Hematological Malignant Bone Tumor: 
• Osteosarcoma > Chondrosarcoma.

• Most Common Benign Bone Tumor: 
• Osteochondroma/Exostosis.

• Most Common True Benign Bone Tumor: 
• Osteoid Osteoma.

Fibrous Dysplasia

Pathology

• Developmental Anomaly: 
• Abnormal development of bone.

• Bone Tissue Replacement: 
• Normal bone tissue is replaced by fibrous tissue.

• Most Common Location: 
• Femur.

X-Ray Features

• Gross/Radiology:
• Shepherd's crook deformity (bending of femur).
• Ground glass appearance (hazy femur).

• Microscopic: Chinese letter appearance of trabeculae, with active spaces.

• Key Point: No osteoblastic rimming.

• Mnemonic:



• Chinese (Chinese letter pattern) shepherd (Shepherd crook deformity) → glass (ground glass appearance) cut his femur → caused bending (bending of femur) → So he made a prosthetic made of fibre (Fibrous dysplasia)
• So he cant rim (No rimming)

Biopsy

• Best Investigation: 
• "Chinese letter pattern appearance"

Treatment

• Bisphosphonates.

McCune-Albright Syndrome

Non-ossifying Fibroma (NOF)

• Microscopic:
• Spindle cells, foam cells and giant cells
• Pink trabeculae with osteoblastic rimming (cells lining the periphery).
• "Non-ossifying" has "No" in its name, so it will have osteoblastic rimming.

Presentation

• 2 - 20 yrs

• Metaphyseal eccentric lesion

• Spontaneously regress

• If large - curettage

Bone Cysts

Simple Bone Cyst (SBC) vs. Aneurysmal Bone Cyst (ABC)

Aneurysmal Bone Cyst (ABC)

• USP 6 rearrangement

• Features: Lots of hemorrhage (aneurysmal).

• Radiology: Cyst looks black due to bleeding.

• Microscopic: Contains blood and giant cells.

Simple Bone Cyst

• Growth Plate Positive: 
• Often seen in children,
• associated with the growth plate.

• Metaphyseal Lesion: Located in the metaphysis.

• Fallen Leaf Sign: 
• A chip of cortex breaks and freely falls down (pathognomonic).

• Trap Door Sign: 
• A chip of bone hinges at the cortex.

• Mnemonic: Simply (Simple bone cyst) fell (Falling leaf) at door (trap door)

Osteochondroma/Exostosis

• Genetic Mutation: 
• EXT1 mutations  
• EXT2 mutations  (from "EXtosis").

• Gross/Pathology:
• Has a cartilaginous cap and
• bony protrusion 
• containing all bone components.

• Radiology: Mushroom-type growth from bone.

General Features

• Most Common Benign Bone Tumor.

• Most Common Site: Distal femur.

• Pathology: Developmental malformation of the growth plate.

• Appearance: Can be
• sessile (flat) or
• pedunculated (stalk-like).

Clinical Features

• Asymptomatic: Usually, grows with the skeleton.

• Pain (Most Common Cause): 
• Bursitis, nerve compression, or fracture.

• Structure: 
• Bony pedicle with
• cartilaginous cap,
• growing away from the growth plate.

• Malignant Transformation: 
• Can transform into chondrosarcoma.

• Signs Indicating Malignant Transformation into Chondrosarcoma
1. > 2 cm cap (on MRI).
2. Heavy calcification of cap (on X-ray).
3. Persistence of growth after skeletal maturity.

Treatment

• Extra periosteal excision
• at skeletal maturity or
• if signs of malignant transformation

Chondrosarcoma (Malignant)

• Radiology:
• Involves axial skeleton (e.g., pelvis).
• Shows permeation.

• lobulated, calcified lesion

• cortical destruction

• Pathology: Very big, bizarre cells.

• Mnemonic: Chondrosarcoma → PP → Pelvis, permeation bb (big, bizarre cells.)

Enchondroma

• Mnemonic: Enne → Idich → kayyum kaalum (hand and foot) vach → Specs (Speckled) ne → stop only (Olliers → only multiple enchondroma) wen Maappu (Maffucci) → Dont permit idi (No permeation)

• Mutation: IDH mutation.

• Radiology: Involves small bones (e.g., fingers).
• Speckled calcification.
• No permeation.

• Pathology: Tiny, benign blue cartilage.

General Features

• Most Common Bone Tumor: 



• In small bones of hands and feet.
• Note:
• M/c tumor of hand: SCC

• Location: Metaphyseal.

• Treatment: Extended curettage + bone graft.

Associated Syndromes

Maffucci's Syndrome:

• Mnemonic: MaffuCHEEE → H & E → Hemangioma, Enchondroma
• Multiple enchondromas.
• Cavernous hemangiomas.
• Lymphangiomas.

• 100% cases are premalignant.

Ollier's Syndrome:

• Mnemonic: Olliee → Only Eeee → Only enchondroma

• Multiple enchondromas.

• 30% cases are premalignant.

Chondroblastoma (Codman Tumor)

• Giant (Giant cells) person called codman () → Stippling (stippled calcification) due to tumor → liked wating chicken () cartilage and drinking coffee (coffee bean)

• Distinction: Not Codman triangle.

• Microscopic Features:
• Giant cells.
• Cells with a line in between → coffee bean nucleus.
• Chicken wire calcification.

Clinical Features

• Also Known As: Codman's tumor.

• Lesion Type: Epiphyseal lesion.

• Most Common In: Children.

• Age Group: 10-25 years (before skeletal maturity).

X-Ray Findings

• Punctate/stippled calcification.

Treatment

• Excision curettage with autologous bone graft.

NOTE: Chicken Wire Appearance, Fried egg, Diens and Mycoplasma

Pattern	Appearance Type	Condition/Location
Fried Egg	Hairy cell leukemia	Bone marrow biopsy
Fried Egg	Seminoma	Testis
Fried Egg	Dysgerminoma	Ovary
Fried Egg	Mycoplasma colonies	Microbiology
Fried Egg colonies on SDA with Olive Oil	Malassezia furfur	Fungus
Chicken Wire	Chicken wire blood vessels.	Oligodendroglioma
Chicken Wire	Chicken wire calcification	Chondroblastoma (bone tumor)
Chicken Wire	Chicken wire blood vessels	Mucinous/Colloid carcinoma of the breast → FNAC
Chicken Wire	Chicken wire fibrosis	Alcoholic liver disease (liver pathology)

• Mnemonic:
• We cannot eat fied egg because it has
1. Fur ()
2. Hair ()
3. Germs (dysgerminoma)
4. Semen (seminoma)
5. Blood (Mycoplasma) in it

• Mnemonic:
• Chicken Breast piece (Breast Ca) um cartilage (Chondroblastoma) um Kallum (Colloid carcinoma, Alcoholic LD)

Mnemonic:

• for Mycoplasma
• Atypical Walking (walking pneumonia) people (PPLO agar) with CAT (Cold agglutination test) → Eat (Eaton agent) fried egg (fried egg colonies) and Dine (Diens stain) → No walls (cell wall deficient) and take steroids (steroid in cell membrane)

• for Diens
• Diens phenomenon → Proteus
• Diens stain → Mycoplasma

Osteoid Osteoma

General Features

• Most Common True Benign Tumor.

• Most Common Site: Femur.

• Age Group: Children and adolescents.

• Location: Diaphysis.

• Lesion Type: Eccentric/cortical lesion.

Clinical Features

• Central Nidus: 
• Produces prostaglandins,
• causing pain.

• Night Pain: 
• Responds well to salicylates (e.g., Aspirin).

• Swelling: 
• In thigh or leg.

X-Ray Findings

• Central lucent nidus (<2 cm).

• Dense surrounding sclerosis.

Treatment

• Mnemonic: Karanjondirikkunna kuttikk Rado=io vach kodukkum

• Pain Relief: NSAIDs.

• Surgical Options:
• Radiofrequency ablation.
• Excision curettage.
• MR guided focused ultrasound destruction.
  (MRgFUS)

Giant Cell Tumor (GCT)/Osteoclastoma

General Features

• Aggressiveness: Locally aggressive.

• Location: Epiphysio-metaphyseal.

• Gender Predominance: Females > Males.

• Age Group: 20-40 years (after skeletal maturity).

• Genetics
• Histone 3 mutation -G34W

Sites

• Most Common: 
• Distal end of femur.

• Others: 
• Proximal end of tibia,
• distal end of radius
  (classical location),
• most common tumor in distal end of radius

Clinical Feature

• Egg Shell Crackling.

Biopsy

• Gross: Lots of haemorrhage (black on X-ray).

• Radiology: Soap bubble appearance.

• Microscopic: Lots of giant cells AND mononuclear cells.
• Multinucleated osteoclast-like giant cells,
• surrounded by stromal mononuclear cells in matrix
• Key Point: Mononuclear cells are the malignant part.

Prognosis

• Local Recurrence: 
• 20% cases.

• Risk of Malignant Transformation: 
• <5% into
• fibrosarcoma or
• malignant fibrous histiocytoma.

• Metastasis: 
• 3% to lungs.

NOTE (PYQ 2018)

• Fibrosarcoma →
• Tumour induced rickets
• Phosphaturia, Osteomalacia
• Hypoglycemia

Treatment

• Denosumab

• Surgical: 
• Extended/extensive curettage + adjuvant treatment.
• Techniques: 
• Phenol,
• liquid nitrogen,
• argon beam,
• high-speed burr,
• H2O2.

Giant Cell Tumor Variants (Tumors rich in giant cells)

• Non-ossifying fibroma (m/c).

• Aneurysmal bone cyst (closest resemblance).

• Chondromyxoid fibroma.

• Chondroblastoma.

• Fibrous dysplasia.

• Simple bone cyst.

• Brown's tumor.

• Osteosarcoma (telangiectatic type).

Chordoma

• Origin: Notochord remnants.

• Site: Usually midline 
1. clivus
2. sacro ileac joint

• Microscopic: Physaliferous cells (very foamy, bubbly cells with white holes).

• Genetic Mutation: Brachyury gene mutation.+

• IHC Marker: Brachyury.

• Mnemonic: Chordoma → Chord (Notochord) pottich → Brake uuri (Barchury gene) → Fysalnte (Physalliform) → bcz he was brown () and bubbly () → his sacro coocygeus () cleave (Clivus) ayipoi

Hemangioma

General Features

• Age Group: Occurs in elderly population.

• Nature: Benign, asymptomatic vascular bone tumor.

X-Ray Hemangioma:

• Site Preference: Spine > Skull > Pelvis.

• Mnemonic: Hemangioma → hemorrhage → Jail il () kidannavane Police (Polka dots) Spine () um skullum () adich bleed cheyipich → kodathiyil (Cordruoy) kond poi

• Mnemonic: Hema malini → wore polka dot and codroy pants → going to jail ()

• Vertical Striations: 
• "Jail bar/Jail house appearance."
• Corduroy Appearance.

CT Scan Hemangioma:

• "Polka dot sign" (Axial view).

Osteosarcoma

• Pathology Hallmark:
• Presence of osteoid 
• (thin, pink, lacy, glassy, unmineralized bone).

• Note: Codman tumor → Chondroblastoma

• Genetics
• p53/RB/INK4/CDK4/MDM2

• Chromothrypsis
• Breaking and joining of chromosomes
• Seen in osteosarcoma

General Features

• Presentation: Bimodal distribution.
• 2nd decade:
• Primary osteosarcoma.
• Older population:
• Secondary osteosarcoma
• due to
• Paget's disease,
• radiation exposure
• Teriparatide
• Primary osteosarcoma > secondary osteosarcoma.

• Location: 
• Metaphyseal
• (Most common: distal femur).

• Radiosensitivity: 
• Most radio-resistant tumor.

• Induced Tumors: 
• Most common radiation-induced bone tumor.

X-Ray Findings

• Sun Ray/Sunburst Appearance.
• D/t periosteal reaction

• Codman's Triangle: 
• Elevated periosteum.

Gross Specimen

• Shows
• striations (sunray/sunburst appearance)
• elevated periosteum (Codman's triangle).

Treatment

• Multi-Stage Approach:
1. Neoadjuvant Chemotherapy: 
1. Prior to surgery.
2. Surgery/Limb Ablation: 
1. Surgical removal of the tumor or limb.
3. Adjuvant Chemotherapy: 
1. Post-surgery.

• Chemotherapeutic Agents (TIO Protocol):
• Actinomycin.
• Cyclophosphamide.
• Bleomycin.
• High-dose Methotrexate.
• Doxorubicin.
• Vincristine.

• Mnemonic: He wants to do acting, cycling, blowing, winning christ, buy rubies and sleep in metha

Myositis ossificans

Ewing's Sarcoma

 

General Features

• Age: Adolescent age group.

• Clinical: Pain, swelling, fever (can mimic osteomyelitis).

• Most Common Tumor: 
• In the 1st decade of life
• peaks in the 2nd decade
• 5-20 years

• Gender: Males > Females.

• Location: 
• Diaphysis of femur (mid-thigh swelling).

• Grade: 
• High-grade sarcoma.

• Most Radiosensitive tumor

• Most chemosensitive tumor

Poor Prognostic Factors

• Metastasis.

• Male gender.

• Age > 12 years.

• Fever, anemia.

• Increased ESR

• Leukocytosis.

• Chemoresistance.

• Relapse.

• Size of the lesion.

Clinical Features

• Presents like an infection.

• Mid thigh/leg swelling.

• Signs of inflammation (clinical and lab).

• Incidental history of trauma.

Biopsy

• Best Investigation
• Small, round blue cells with pseudo-rosettes.
• Cells are PAS positive (due to glycogen) & diastase digestible.

• CD99 / MIC2 positive on IHC.
• Specific marker.

• Homer Wright rosettes or pseudomedullary rosettes
• Center → filled
• Mnemonic: Psudo friends → hide something inside their heart

 

• Flexner Winterstener Rosette
• Center → Pale or white
• Mnemonic: True friends wants what is good for you → heart (centre) is pure white
• Found in small round blue cell tumor

• Homer-Wright → pseudo rosettes.

• Mnemonic: MEN () R () Wright () and Men are Pseudo, Men are Blast
• Medulloblastoma
• Ewings/Ependymoma
• Neuroblastoma
• Retinoblastoma
• (Both rosettes → seen in Retinoblastoma).

Genetics

• Gene Fusion: 
• EWS - FLI1 fusion 
• (EWS and FLI, as wings help you fly).

• Karyotyping (Most Common Translocation): 
• Translocation t(11;22).

• Other Translocations: 
• t(21;22), t(7;22).

• Trisomy 8, Trisomy 21.

X-Ray Findings

• Onion Peel/Lamellated Appearance: 
• Layers of new bone.
• (periosteal reaction with layers).

Treatment

• Multi-Modal: 
• Chemotherapy +
• limb salvage/resection ±
• adjuvant radiation.

• Radiosensitive: 
• not preferred
• d/t ↑↑ chance of recurrence and secondary malignancies.

• Cystic BRAIN TUMORS
• Craniopharyngioma
• JPA

Marker	Positive In	Mnemonic / Note
Cytokeratin (CK)	Carcinoma	C for C
Vimentin	Sarcoma	ㅤ
CD45 / LCA Leucocyte Common Antigen	Lymphoma	L for L
HMB45 S 100	Melanoma	M for M
CD1A	Langerhans Cell Histiocytosis (LCH)	ㅤ
CD99	Granulosa Cell Tumor (ovary)	99-year-old granny
(MIC2)	Ewing Sarcoma (bone)	Mitu → childhood tumor
Glial Fibrillary Acidic Protein (GFAP)	Tumor markers in glioma (Astrocytoma, Glioblastoma multiforme)	ㅤ
Lamin	Progeria: Disorder of premature ageing (Hutchinson Gilford)	ㅤ

• Mnemonic:
• Sarcoma
• Vimal Sar
• Also remember Rape (Rhabdomyosarcoma) Syn (Synovial) Mnemonic
• Car
• Sit (Cytokeratin) inside Car
• Remember car → bike → took another route
• Helmet (HCC → Fibrolamellar)
• Rc book (RCC)
• Phone (Follicular CA)
• Granulosa cell tumor mnemonic
• 99 year old granny ex ne vilikkan poi.
• (99 (CD 99) year old granny → hyper estrogenism () → Called Ex (Call exner) → offered coffee (coffee bean) → she shouldve inhibited (inhibin) her)
• Ewings sarcoma Mnemonic:
• Mittu (MIC2) (11 year old) → Onion () kazhichapo wings () vannu → to Wings to Fly (EWS-FLI1) in Right (Homer wright) direction to get Pasta (Pas +ve).
• Mittu thirichu vannapo 22 vayassai (t(11:22))

Condition	Feature
NF1	Chromosome 17
NF2	Chromosome 22
DermatoFIBROSARCOMA protrubans	t (17;22)
Nodular Fascitis	t (22;17)