Musculoskeletal, CT & Skin patho Flashcards
In all 4 cases of Osteogenesis imperfecta, the cause is ……
defect in the synthesis of type I collagen (abnormal pro-1(1) or pro-2(1) chains)
* It is inherited as an autosomal dominant trait
What is defect caused by Osteogenesis imperfecta in each of the following organs:
- Bone
- Eye
- Teeth
- Ears
- Heart
- Skin
- Woven bone instead of trabecular, abnormal arrangement of collagen fibers leading to lax ligaments, fractures
- Sclera with blue hue
- Small & discolored (dentinogenesis imperfecta)
- Deafness due to fractured ossicles
- Mitral valve prolapse
- Abnormally thin dermis
Define osteopetrosis
Hereditary disorder, characterized by increased thickness of cortical bone and narrow medullary bone
- Bone is brittle
- Membranous bone are not affected
- AKA Albers-Schonberg disease
Osteopetrosis is associated with …..
Blindness, deafness, anemia, cranial nerve palsies, hydrocephalus
Osteopetrosis is inherited via ……
autosomal dominant and recessive pattern
The main cause of osteopetrosis is …….
the inability of the osteoclasts to resorb bone
* ALP is elevated
Achondroplasia is the best known form of ……
It is characterized by …………
dwarfism
- short limbs (due to defect in epiphyseal bone formation), frontal bossing, saddle nose & large body
- Autosomal dominant inheritance
Define osteochondromatosis
Hereditary exostoses
* Example is Gardner syndrome
What are the causes for osteoporosis?
Estrogen deficiency, low density of bone, lack of exercise, nutritional factor, endocrinopathies
What are the clinical features of osteoporosis?
- Xray Shows ……
- Serum values are …….
Bone pain & spontaneous fractures, radiolucency of bone
* normal Ca, Phosphorus. ALP serum level is variable
Most susceptible bones to fracture due to osteoporosis are …….
vertebrae & femoral neck
* There is thinning of cortical bone in all bones, but the bone histology is normal
Osteomalacia and rickets are both caused by …
Vit D deficiency (from chronic renal insufficiency, intestinal malabsorption, or dietary deficiency) leading to disorder of osteoid mineralization.
Rickets occur in children prior to …….
closure of epiphysis, causing deformation & bowing of legs, fractures and pain
Rachitic rosary is ….
prominent knobs of bone at the costochondral joints of rickets patient
* Deficiency of Ca results in lack of mineralization and an overgrowth of costochondral joint cartilage.
Serum findings in a patient with osteomalacia are …..
Low Ca and phosphorus, ALP is elevated (which distinguishes this syndrome from osteoporosis)
* There is diffuse radiolucency of bone on Xray
What are the clinical features of Paget disease?
bone pain, deformity and fractures, affecting many bones (polyostotic), increased warmth of the skin overlying the affected bone
- X ray shows enlarged radiolucent bones
- ALP is very high
- Skull enlargement is a classic sign. Impingement of the nerves may cause deafness or facial pain
In Paget disease, the disease progresses from ….. to ……
The resorbed bone is replaced by …….
Osteolytic to osteoblastic
* Vascular CT (which mineralizes later), with “mosaic” (or jigsaw) rather than trabecular pattern, with persistent osteoid seam (new non mineralized bone) at the margins
What are the two types of osteomylitis?
- Pyogenic: caused by “Staph”, Strep, gonococci, H. influenzae
* Pseudomonas is common in IV users & diabetics
* Salmonella is common in sickel cell patients - Tuberculous: in 1% of TB cases. Caseating granulomas of bone
What are the specific findings of pyogenic osteomylitis?
Necrotic sequestrum, surrounded by new bone (involucrum).
* Brodie abscess is localized abscess withing the bone
Osteoma is …….
Hyperostosis frontalis interna is …….
benign tumor of bone.
* osteoma extending in the orbit or the sinuses
Osteoid osteoma is ……
benign tumor of the diaphysis of long bones
Osteoblastoma is …..
Similar to osteoid osteoma, often in the vertebrae
* Could be malignant
Osteosarcoma is …..
What are the clinical features?
What is the prognosis?
malignant bone tumor, associated with Paget disease. Often in the metaphysis ends of bones
- Localized pain and swelling, weight loss, anemia
- Prognosis is poor with possible lung metastasis
Codman Triangle is …….
Elevated periosteal bone due to underlying tumor
* It is a classic xray sign for osteosarcoma
What is the microscopic finding of osteosarcoma?
anaplastic cells with osteoid that is variably mineralized. May contain collagen or cartillage, or could be sclerotic
Osteochondroma is ……
exostosis from misdirected growth of growth plate
Enchodndroma is …..
solitary benign growth of cartilage, inside the bone
Chondrosarcoma is …….
Usually found in …….
malignant tumor of chondroblasts, slower growing than osteosarcoma. There is atypical chondrocytes and chondroblasts
- spine, pelvis, upper limbs
- There is pain and swelling
Giant cell tumor is …….
malignant tumor containing multinucleated giant cells and atypical stromal cells
- Rare
- There is expanding area of radiolucency without a sclerotic rim on Xray, usually in the epiphyseal region of long bones
Ewing sarcoma is ……..
Most common locations are …….
What are the clinical features?
malignant neoplasm of undifferentiated mesenchymal cells within the bone marrow
- Rare
- Commonly in the Metaphyses, pelvis
- Tumor erodes through the cortex and invade the surrounding tissue. There is concentric layers of new bone (onion skin)
What are the clinical features of suppurative arthritis?
What are the causative agents?
Tender, red & swollen joint. Usually monoarticular. Synovial fluid is cloudy and filled with neutrophils
* Caused by strep., staph. & gonococcus
What are the clinical features of tuberculous arthritis?
Usually, insidious onset & joint destruction. Often in the spine & hip
* Synovial lining is covered with tubercles and granulation tissue (Pannus), which may cause destruction of the joint space
Osteoarthritis is caused by …….
The predisposing factors are ….
wear and tear of joints, with erosion of articular cartilage leading to eburnation of bone.
- Obesity, joint injury, synovial disease
- Note: less joint space on Xray
What are the clinical features of osteoarthritis?
joint stiffness, decreased range of motion, effusion, crepitus, and bony swelling
Joint mice are …..
flakes of cartilage in the joint space from erosion
* Common finding in osteoarthritis
Osteophytes are ……..
bony projection that are formed along the joint margins
- Also called bony spurs
- Common finding in osteoarthritis
Heberden nodes are ……….
bone swelling found at the distal interphalangeal (DIP) joints of fingers
* Common finding in osteoarthritis
In rheumatoid arthritis, …….. is formed against Fc fragment of IgG, resulting in immune complex
rheumatoid factor
What are the common clinical features of rheumatoid arthritis?
- Morning stiffness, with low grade fever
- Joint swelling, redness & warmth. Ankylosis may develop
- Increased neutrophil & decreased mucin in the synovial fluid
- High ESR & hypergammaglobulinemia
- Erosion & osteoporosis in Xray
- Systemically, there is Sjögren’s syndrome, subcutaneous nodules, glaucoma, vasculitis (due to antigen-antibody complex), hepatosplenomegaly
Rheumatoid arthritis usually affect ……
the small joints in hand and feet, in a symmetrical manner
* There is synovitis with pannus formation (vasculrized mass packed with lymphocytes, macrophage & plasma cells)
Rheumatoid nodules are ……
connective tissue with central necrosis found in the skin, heart valves, lung, pleura, spleen.
* Skin nodules are on the extensor surfaces
Gout is ……
deposition of monosodium urate in joints
* There is hyperuricemia
What are the types of gout?
- Primary: 90% of cases, due to underexcretion of urate in urine
- Secondary: due to over production of uric acid (disorder in purine metabolism)
What are the clinical features of gout?
Acute arthritis (swelling, redness & pain). Within 10 years, chronic disability ensues
- Big toe is the most affected
- Tophi (urate deposit surrounded by inflammatory cells) are pathognomonic. May form in the helix of ear, bursae, ligaments & kidney
Bursae are ……..
small, synovial fluid filled sacs, lined by synovial membrane. Act as a cushion for all the major joints
Seborrheic keratoses are ……, may appear following ……. or ……..
benign tumor, due to sun exposure,
follow inflammatory dermatitis, hormonal therapy, or underlying malignancy (like colon cancer)
* The lesions are gray, greasy, with hyperkeratosis. There could be pseudo horn cysts (filled with keratin)
* Also called basal cell papilloma, or brown warts
* They have “stuck on” appearance
Keratoacanthoma is ……
What is the key feature on the lesion??
benign squamous lesion in sun exposed areas
- Rapidly growing pink papule with a keratin filled center, resembles SCC
- The key feature is the normal (nondysplastic) epidermis on both sides of the central keratin
Fibroepithelial polyps (skin tags) are ……
benign squamous epithelial lesions covering a fibrovascular core.
* Common finding. High numbers may indicate diabetes
Basal cell carcinoma is …..
Locally aggressive lesion, but don’t metastasize. The most common skin cancer
- Occur in sun exposed areas, in faces of fair skin people
- Palisading cells at the edge of tumor cells nest is a microscopic feature
- It is a gray papule with heaped up borders and central depression
- Treated with complete excision
Actinic keratoses are …..
rough, crusty, red papule up to 1 cm in diameter.
- Premalignant (may develop into SCC)
- Associated with sun exposure. Common in fair skinned people
Squamous cell carcinoma is ……
What are the causative factors?
malignant, often in sun exposed areas.
- Sun exposure, skin ulcers, long term exposure to hydrocarbons, burns & radiation
- Grossly, it comes in many forms, with leukoplakia on the mucosal surface (made white by keratin)
What is the difference between sun exposed and non sun exposed SCC lesions?
Rarely metastasizes (in sun exposed areas),. While on non exposed metastasizes
What are the microscopic finding of a SCC lesion?
Atypical cells in the epidermis (SCC in situ) or invading the dermis.
* These cells may form squamous pearls (onion skin surrounding a central keratinization)
Xanthomas are ……
A collection of lipid laden histiocytes with eosinophilic cytoplasm in the dermis, in the form of yellow nodules.
* Associated with hyperlipidemia
Strawberry hemangioma is also called ……
capillary hemangioma
- Composed of thick walled capillaries, usually in the first weeks of life
- Resolve spontaneously
Nevocellular nevus is ……
benign tumor of nevus cells & melanocytes
- Could be junctional, compound or intradermal
- Related to sun exposure.
Melanomas tend to spread …….
horizontally before vertically.
* Prognosis depend on the depth of vertical invasion
*
Lentigo maligna melanoma arises from ……
lentigo maligna
* This has the best prognosis
Nodular melanoma is …….
melanoma with extensive dermal (vertical) invasion. Has the worst prognosis
* Black-brown lesions, found on the skin or mucosa
Staging of melanoma depends on …….. . Treatment is …….
depth of vertical invasion
* Treatment is complete excision. Chemotherapy and immunotherapy also used
Bullous pemphigoid is …..
The cause is probably …..
Large, tense, pruritic bullae in the mouth (rare) or lower body
- The bullae contains eosinophils
- Circulating antibody (IgG) against the dermoepidermal junction
- Self limited
- Rare, but more common than pemphigus vulgaris
Pemphigus vulgaris is …….
It is caused by …….
small flaccid vesicles, usually on the mucous membranes
- Caused by circulating antibodies (IgG) against the junctions between the keratinocytes, causing acantholysis (The bullae contain floating keratinocytes)
- Treatment is steroids
Nikolsky sign is used to ……
confirm pemphigus vulgaris. By rubbing the skin with the finger
Impetigo is caused by …..
group A beta hemolytic streps, or staph
- Eroded pustules covered by honey colored crusts. Highly contagious
- May lead to glomerulonephritis (poststreptococcal glomerulonephritis)
Molluscum contagiosum is ……
viral infection, caused by DNA poxvirus (infect only humans)
- Multiple small, firm, umbilicated papules. Also called water warts
- There are virus clusters in the keratinocytes
Verrucae are caused by …..
human papillomavirus (HPV)
- There is epidermal hyperplasia, with keratosis and parakeratosis
- Also called plantar wart
Fungal infections are usually confined to the ……. . It is commonly caused by ……, ……., …….
cornified layer of epidermis
Trichophyton rubrum, Microsporum, Malassezia
Define:
- Tinea capitis
- Tinea corporis
- Tinea vesicolor
- Cradle cap, affects the scalp, usually in children. Caused by Trichophyton & Microsporum
- Infects the trunk and extremities in children. Also know as ringworm, but it is not a worm
- Causes hyper or hypo pigmented macules
Define:
- Tinea pedis
- Tinea cruris
- Tinea unguium
- Causes athlete’s foot
- Causes Jock itch (underwear)
- Causes thickening and discoloration of the nail bed. Also called onychomycosis. Hard to treat
Scalded skin syndrome is ……
caused by S. aureus exfoliative toxin, usually in children (under 6)
- Several easy to rupture bullae
- Nikolsky sign may be positive. The disease is confirmed with S. aureus in blood or biopsy
Urticaria is …….
transient, raised, pruritic pink wheals characterized by dermal edema
What are the forms of eczema?
- Atopic dermatitis: unknown etiology, family history
- Contact dermatitis: From irritant exposure
- Lichen simplex chronicus: chronic itching causes thickening of the skin, which causes more itching
Erythema multiforme is …..
hypersensitivity to drugs (penicillin, sulfonamides), infections (herpes, mycoplasma), collagen vascular disease, or malignancies
- It is uncommon. There is symmetrical involvement of the limbs
- Usually self limited
Acne vulgaris causes …… . It is related to ……..
An allergy to ……. is clearly involved
comedones, papules & cysts
- Hormonal change, drugs, diet, irritants & genetic factors
- Propionibacterium acnes
Rosacea is …..
lesion affecting the central face.
* There is erythema, telangiectasias, acneiform lesions (papules, cysts, pustules) and rhinophyma (telangiectasia and hyperplasia of the mucous membrane in the nose)
Squamous papilloma infection of the oral mucosa is caused by ………
HPV genotype 6 & 11
