MedicoNotebook

1 Important Bone Tumors

Author: Dr Ayush Goel

Important Bone Tumors:

1. Osteosarcoma:

Age: 10-20 yrs (except when its secondary e.g. in Paget's disease in old age)
Metaphyseal
Sunray periosteal reaction

note: sunburst calcification on abdominal X-ray is seen in Pancreatic serous cystadenoma

Codman triangle

note: codman tumor is chondroblastoma

Radioresistant

2. Ewing's sarcoma

Age: 10-20 yrs
laminated periosteal reaction: onion skin
location: diaphyseal
Radiosensitive

3. Giant cell tumor (GCT) = osteoclastoma

Epiphyseal

other epiphyseal lesions - Chondroblastoma, Geode

Soap bubble appearance
Metaepiphyseal: Seen after fusion of epiphysis (age 20-50 yrs)

4. Vertebral hemangioma

X-ray and Sagittal CT: Corduroy cloth appearance
Axial CT: Polka dot appearance

5. Adamantinoma

Mandible (Ameloblastoma): 3rd-5th decade
Tibial diaphysis: 10-20 yrs, typically anterior cortex
Pituitary (Both pituitary stalk and enamel arise from oral epithelium)

6. Above 60 years, multiple lytic lesions

Multiple myeloma

Normal alkaline phosphatase, cold on bone scan
punched out lytic lesions

Metastases

Increased alkaline phosphatase, hot on bone scan i.e. high uptake

7. Metastases

Sclerotic/osteoblastic

Commonly from: Prostate and Breast (can have mixed)
Other: Stomach, Carcinoid

Lytic and expansile

Commonly from Kidney and Thyroid

8. Hyperparathyroidism

subperiosteal bone resorption

radial aspect of proximal and middle phalanges of the 2nd and 3rd fingers
lamina dura: floating teeth

Salt and pepper skull = pepper pot skull
Brown tumor
erosion of lateral end of clavical
rugger jersey spine (secondary hyperparathyroidism due to renal osteodystrophy)

note: picture frame vertebra is seen in Paget's disease of bone (also Cotton wool skull in Paget's)
note: sandwich vertebra is seen in osteopetrosis

9. Eosinophilic granuloma

children
beveled edges
vertebral plana
floating teeth (also seen with hyperparathyroidism)

0 Pulmonary aspergillosis

Pulmonary aspergillosis can present in 3 major forms:

Aspergilloma

fungal ball in an old tuberculous cavity
shows Monad sign (usually also called air crescent sign)

Allergic bronchopulmonary aspergillosis (ABPA)

central bronchiectasis
gloved finger appearance
fleeting opacities

Invasive aspergillosis

in immunocompromised
shows CT halo sign

Note: Reverse CT halo/Atol sign is seen in Cryptogenic organizing pneumonia/bronchiolitis obliterans organising pneumonia (COP/BOOP)

air crescent sign - it defines improvement/recovery in the underlying lesion with increased granulocyte activity (should not be confused with Monad sign which is also called air crescent sign as the air outlining the fungal ball is also in the shape of crescent)

Author: Dr Ayush Goel

421. For lung investigation - CT scan is best, except in Pancoast tumour/Superior sulcus tumour where MRI is investigation of choice to look for brachial plexus involvement.

422. Silhouette's sign or more correctly loss of silhouette sign:

Middle lobe pathology: obscures right heart border
Lower lobe pathology: obscures diaphragm
Lingular pathology: left heart border
Posterior segment of left upper lobe: aortic knuckle
Also see this MCQ: here

423. Lordotic chest X-ray view is used for:

Middle lobe examination (best view)
Lung apex pathology
Interlobar fissural effusion

424. Mammography:

screening in >40 yr females - once yearly
to detect DCIS - MRI is best (done in 2nd week of menstruation)
in young female, mammography is not useful as there is a lot of glandular tissue that makes the breast very dense
Most common sign of malignancy seen on mammogram: microcalcification
Popcorn calcification in breast: Fibroadenoma {Note: Popcorn calcification in lungs - pulmonary hamartoma, it also has fat in the lesion}

425. Radiation doses:

Extremity X-ray = DEXA < Chest X-ray < Mammography < CT head < CT chest < CT Abdomen and pelvis < Coronary CT angiography < PET/CT
Barium studies have doses close to CT head, except Barium enema which has dose just less than CT chest.

426. HRCT Lung - uses bone algorithm for image reconstruction, useful for: