MSK/ Derm pathology Flashcards
- repetitive flexion (forehand shot) causing pain near epicondyle
- repetitive extension (backhand shot) causing pain near lateral epicondyle
- medial epicondylitis
- lateral epicondylitis
boxer’s fracture, commonly caused by direct impact with closed fist (punching a wall)
seen in 4th and 5th metacarpals
metacarpal neck fracture
entrapment of median nerve in carpal tunnel (between transverse carpal ligament and carpal bones) –> nerve compression–> paresthesia, pain, and numbness in distribution of median nerve
patient comes in with thenar eminence atrophies but sensation spared, because palmar cutaneous branch enters hand external to carpal tunnel
positive tinel sign sign and phalen maneuver
associated with pregnancies (due to edema), RA, hypothyroidism, diabetes, acromegaly, dialysis-related mayloidosis; may be associated with repeitive use
carpal tunnel syndrome
compression of ulnar nerve twist. classically seen in cyclist due to pressure from handlebar
Guyon canal syndrome (both the ulnar nerve and ulnar artery runs through the Guyon canal)
inflammation of the gluteal tendon and bursa lateral to greater trochanter of femue.
treatment with NSAID, heats, and stretching
trochanteric bursitis
common injury in contact sport due to lateral force applied to planted foot. consost of damage to the ACL, MCL, and medial meniscus (attached to the MCL)
however, lateral meniscus involvement is most common than medial meniscus involvement in conjunction with ACL and MCL injury. presents with acute knee pain and signs of joint injury/instability
this is the unhappy triad
inflammation of the prepatellar bursa in front of the knee cap due to repeated trauma or pressure from excessive kneeling (housemaid’s knee)
prepatellar bursitis
popliteal fluid collection in gastrocnemius-semimembranosus bursa commonly communicating with synovial space and related to chronic joint disease (osteoarthritis and rheumatoid arthritis)
baker cyst
non-inflammatory thickening of abductor pollicis longus and extensor pollicis brevis tendons characterized by pain or tenderness at radial styloid.
positive Finkelstein test (pain at radial styloid with active or passive stretch of thumb tendons). risk in new mothers, golfers, racquet sport players
De Quervain tenosynovitis
fluid-filled swelling overlying joint or tendon sheath, most commonly at dorsal side of wrist. Arises from herination of dense connective tissue
ganglion cyst
overuse injury of lateral knee that occurs primarily in runners. pain develops secondary to friction of iliotibial band against lateral femoral epicondyle
iliotibial band syndrome
increase pressure within fascial compartment of limb (defined by pressure different of 30mmHg or less between the tissue compartment pressure and distolic blood pressure)–> venous outflow obstruction and arteriolar collapse–> anoxia and necrosis.
causes include significant long bone fractures, reperfusion injury, animal venoms
present with severe pain and tense, swollen compartments with limb flexion. motor deficits are late sign of irreversible muscle and nerve damage
limb compartment syndrome
also called shin splints. common cause of shin pain and diffuse tenderness in runners and military recruits. caused by bone resorption that outpaces bone formation in tibial cortex
medial tibial stress syndrome
inflammation of plantar aponeurosis characterized by hell pain (worse with first steps in the morning or after period inactivity) and tenderness.
plantar fasciitis
abnormal acetabulum development in newborns. result in hip instability/dislocation. commonly tested with ortolani and barlow maneuvers (reveal “clunk”)
confirmed via ultrasound (x-ray not used until 4-6 months because cartilage is not ossified)
treatment: splint/harness
developmental dysplasia of the hip
idiopathic avascular necrosis of femoral head. commonly presents between 5-7 years with insidious onst of hip pain that may cause child to limp. more common in males
initial xray is normal
Legg-Calve-Perthes disease
overuse injury casued by reptitive strain and chronic avulsion of secondary ossification center of proximal tibial tubercule. occurs in adolescents after growth spur.
common in running and jumping athletes. presents with progressive anterior knee pain
overuse injury that commonly presents in young, female athetes as anterior knee pain.
exaberbated by prologed sitting or weight-bearing on flexed knee.
Tx: NSAIDs, thigh muscle strengthening
patellofemoral syndrome
also called nursemaid’s elbow
common elbow injury in children <5 yo. caused by sudden pull on arm–> immature annular ligament slips over head of radius.
injured arm held in extended/slightly flexed and pronated position
radial head subluxation
classically present in an obese (12yo) child with hip/knee pain and altered gait. increased axial force on femoral head–> epiphysis displaces relative to femoral neck (like a scoop od ice cream slipping off a cone)
dx with xray and tx with surgery
slipped capital femoral epiphysis
incomplete fracture extending partway through width of bone following bending stress; bone fails on tension side; compression side intact (compar to torus fracture). bone is bent like a green twig
greenstick fracture
axial force applied to immature bone–> cortex buckles on compression (concave) side and fractures.
Tension (convex) side remains solid (intact)
torus (buckle) fracture
failure of longitudinal bone growth (endochondral ossification)–> short limbs, membransous ossification is not affected–> large head relative to limbs
constitutive activation of fibroblast growth factor (FGFR3) actually inhibits chroncyte proliferation. >85% of mutations occur sporadically; autosomal dominant with full penetrance (homozygosity is lethal)
associated with increase paternal age
most common cause of short limbed dwarfism
achondroplasia
trabecular (spongy) and cortical bone lose mass and interconnections despite normal bone mineralization and lab values (serum Ca and PO4)
most commonly due to increase bone resorption related to decreased estrogen and old age,
secondary to drugs (steroids, alcohol, anticonvulsantsm anticoagulant, thyroid replacement therapy)
other condition (hyperparathyroidism, hyperthyroidism, muliple myeloma, malabsorption syndrome)
DEXA at lumbar spine, total hip, femoral neck, with T score of < 2.5 or by fragility fractures. (fall from standing height, minimal trauma) at hip or vertebra.
one time screening recommended in women > 65 yo
Tx: bisphosphonate, teriparatide, SERMs, rarly calcitonin, denosumab (monoclonal antibody against RANKL
failure of normal bone resorption due to defective osteoclast–> thickened, dense bones that are prone to fracture, mutation (carbonic anhydrase 2) impair ability of osteoclast to generate acidic environment neccessary bone resorption. overgrowth of cortical bone fills marrow space–> pancytopenia, extramedullary hematopoeisis
can result in cranial nerve impingment and palsies due to narrowed foramina
xray- show diffuse symmeteric sclerosis (bone-in-bone) “stone bone”. bone marrow transplant is potentially curative as osteoclast ferived from monocytes
osteopetrosis
defective mineralization of osteoid (osteomalacia) or cartiliaginous growth plates (rickets)
most commonly due to vitamin D deficiency
xray: osteopenia and looser zones (psuedofractures) in osteomalacia. epiphyseal widening and metaphyseal cupping/fraying in rickets
childrens with rickets have pathologic bow legs, bead-like costochondral junctions (rachitic rosary), craniotabes (soft skull)
decrease vit D–> decrease Ca–> increase PTH secretion –> decrease serum PO4
hyperactivity of osteoblast–> increase alkaline phosphotases
osteomalacia/rickets
aka Paget disease of bone . common, localized disorder of bone remodeling caused by osteoclastic activity followed by increase osteoblastic activity that form poorly formed bones
serum Ca, phosphorus, and PTH levels are normal.
increase ALP
mosaic pattern of woven and lamellar bone (osteocytes within lacunae in choatic juxtapositions); long bones chalk-stick fractures. increase blood flow from increase arteriovenous shunt may cause high-output heart failure
increase risk of osteosarcoma
hat size can increased (skull thickening), hearing loss is common due to auditory foramen narrowing
stages of Paget disease:
Lytic-osteoclasts
mixed-osteoclast + osteoblast
sclerotic-osteoclast
quiescent-minimal osteoclast/osteoblast activity
tx with bisphosphonates
Osteitis deformans
avascular necrosis of bone
femoral head is the most common site of infarction (watershed zone ) due to insufficiency medial circumflex femoral artery)
corticosteroids, alcoholism, sickle cell, trauma, SLE, Legg-Clave-Perhes disease, Gaucher disease, slipped capital femoral epiphysis
components
Disorder, serum Ca, PO4, ALP, PTH, comments
Osteoporosis-same in all, decrease bone mass
osteopetrosis-decrease serum Ca or same, rest are the same, dense, brittle bone, Ca decrease in severe case, malignant disease
paget disease of bone- increase ALP, same in rest, abnormal “mosaic” bone architecture”
osteitis fibrosa cystica ( and primary hyperparathyroidism)-PO4 decrease, increase in rest, brown tumors due to fibrous replacement of bone, subperiosteal thinning
secondary hyperparathyroidism-decrease Ca, increase in rest, compensation for CKD (decrease PO4 excretion and production of activated vit D)
Osteomalacia/rickets- decrease in Ca and PO4, increased in rest, soft bones, vitamin D deficiency also causes secondary hyperparathyroidism
Hypervitaminosis D- increase Ca, PO4, decrease PTH, same ALP, caused by oversupplementation or granulomatous disease (sarcoidosis)
primary bone tumors (benign)
components in this order
Osteochondroma-most common in male <25yo, located: metaphysis of long bones characterized: lateral bony projection of growth plate (continous with marrow space) covered by cartilaginous cap. rarely transform to chondrosarcoma
Osteoma- middle age, located: surface of facial bones, characterized: associated with Gardner syndrome
Osteoid osteoma-adults <25, male > female located: cortex of long bones, characterized: presents as bone pain (worse at night) that relieved by NSAIDs, bony mass (<2cm) with radiolucent osteoid core
Osteoblastoma- male> female, located: Vertebrae, characterized: similar histolgy to osteoid osteoma. larger size (>2cm), pain unresponsive to NSAIDs
Chondroma-located in medulla of small bones of hand and feet, characterized by benign cartilage
giant cell tumor- 20-40 yo, located epiphysis of long bones (often in knee region), characterized: locally aggressive benign tumor. Neoplastic mononuclear cells that express RANKL and reactive multinucleated giant (osteoclast-like) cell “osteoclastoma. “soap bubble” apperance on xray
malignant tumors
osteosarcoma (osteogenic sarcoma) <20yo males, less common in elderly, located: metaphysis of long bones (often in knee region), characteristic: pleomorphic osteoid-producing cells (malignant osteoblasts), presnts as painful enlarging mass or pathologic fractures, Coman triangle (from elevated periosteum) or sunburnt pattern on xray.
predisposing factors: paget disease of bone, bone infarcts, radiation, familial retinoblastoma, Li-Fraumeni syndrome
Chondrosarcoma: located: medulla of pelvis, proximal femur and humerus, characterized: tumor of malignant chondrocytes
Ewing sarcoma-most common in caucasians. generally in boy < 15 years, located: diaphysis of long bones (femur), pelvic and flat bones, characterized: anaplastic small blue bells of neuroectodermal origin, t(11;22)-fusion of EWS-FLI1, onion-skin periosteal reaction in bone, aggressive with early metastatases
Osteoarthritis-mechanical -wear and tear destroys articular cartilage (degenerative joint disorder)–> inflammation with inadequate repair. Chondrocytes mediate degradation and inadequate repair, presentation: pain in weight-bearing joints after use (end of the day), improved with rest. asymmetrical joint involvement. knee cartilage loss begins medially (bowlegged) no systemic symtpoms, Joint finding: osteophytes (bone spurs) joint space narrowing subcondral sclerosis and cyst. synovial fluid noninflammatory (WBC < 2000) development of Heberden nodes-high, involves DIP, Bouchard nodes (below, involves PIP) and 1st CMC, not MCP, treatment: activity modification, acetaminophen, NSAIDs, intra-artcular glucocorticoids
predisposing: age, female, obesity, joint trauma
Rheumatoid arthritis- autoimmune inflammation induces formation of pannus (proliferative granulation tissue) which erodes articular cartilage and bone, presentation: erosion, juxta-articular osteopenia, soft tissue swelling, subchondra; cyst, joint space narrowing. deformities: cervial subluxation, ulnar finger deviation, swan neck, boutonniere-deformed position of the fingers or toes, in which the joint nearest the knuckle (the proximal interphalangeal joint, or PIP) is permanently bent toward the palm while the farthest joint (the distal interphalangeal joint, or DIP) is bent back away (PIP flexion with DIP hyperextension)., involves PIP, MCP, wrist, not DIP or CMC. synovial fluid inflammatory, Treatment: NSAIDs, steroids, methotrexate, sulfasalazine, hydroxyxhloroquine, leftunomide), biologic agent (TNF-alpha inhibitor)
predisposing: HLA-DR4, positive RF, symetrical joint involvement
extraarticular manifestation: rheumatoid nodules (fibrinoid necrosis with palisading histiocytes) in subcutaneous tissue and lung (positive pneumoconiosis–> Caplan syndrome) interstitial lung disease, pleuritis, pericarditis, anemia of chronic disease, neutropenia + spenomegaly (Felty syndrome) AA amyloidosis, Sjogren syndrome, scleritis, carpal tunnel syndrome
inflammation of monoarthritis caused by precipitation of monosodium urate crystal in joints
- underexcretion of uric acid-largely idiopathic, potentiated by renal failurem exacerbated by thiazide and diuretics
2. overproduction of uric acid: lesch-Nyhan syndrome, PRPP excess, increase cell turnover (tumor lysis syndrome, von Gierke disease
crystals are needle shaped and negative birefringent under polarized light (yellow under parallel light, blue under perpendicular light) serum uric acid can be normal in acute gout.
sx: asymmetric joint distribution, joint swollenm red, painful. (MTP of big toe aka podagra), tophus formation (in external ear, olcranon bursa, achilles tendon), attack tends to occur after large meals with food rich in purines (red meat and seafood), dehydration, alcohol consumption (alcohol competes for same excretion site as uric acid.
treatment with NSAIDs (indomethacin) , steroids, colchicine. chronic: preventive: xanthine oxidase inhibitor (allopurinol, febuxostat)
Gout
aka pseudogout. deposition of calcium pyrophosphate crystals within the joint space. occurs in patients > 50 yo; both sex affected equally
associated with hemochromatosis, hyperthhyroidism, joint trauma
pain and swelling with acute inflammation (pseudogout) and chronic degeneration (psuedo-osteoarthritis). knee most commonly affect joint
chondrocalcinosis (cartilage calcification) on xray
crystals are rhomboid and weakly positive birfringent under polarized light (blue when parallel to light)
acute treatment: NSAIDs, colchicine, steroids
prophylaxis: colchicine
calcium pyrophosphate deposition
systemic juvenile idiopathic arthritis
systemic arthritis seen in < 12 yo presents with daily feverm salmon-pink macular rashm arthritis (commonly 2+ joints) frequently presents with leukocytosism thrombocytosis, anemia : icnrease ESR, CRP,treatment: NSAIDs, steroids, methotreaxtae, TNF inhibitor
autoimmune disorder characterized by destruction of exocrine glands (especially lacrimal and salivary) by lymphocytic infiltrates
40-60yo
Findings:
. Inflammatory joint pain
. Keratoconjunctivitis sicca (tear production
and subsequent corneal damage)
. Xerostomia ( saliva production B )
. Presence of antinuclear antibodies,
rheumatoid factor (can be in the absence of
rheumatoid arthritis),
antiribonucleoprotein
antibodies: SS-A (anti-Ro) and/or SS-B (anti-
La)
. Bilateral parotid enlargement
Anti-SSA and anti-SSB may also be seen in
SLE. ⊕ Anti-SSA in pregnant women with
SLE –> increase risk of congenital heart block in the
newborn.
A common 1’ disorder or a 2’ syndrome
associated with other autoimmune disorders
(eg, rheumatoid arthritis, SLE, systemic sclerosis).
Complications: dental caries; mucosa-associated
lymphoid tissue (MALT) lymphoma (may
present as parotid enlargement).
Focal lymphocytic sialadenitis on labial salivary
gland biopsy can confirm diagnosis.
Septic arthritis
picture: A. lymphocytic infiltrates. B) xerostomia (decrease saliva production) –> mucosal atrophy, fissuring of the tongue
S aureus, Streptococcus, and Neisseria gonorrhoeae are common causes. Affected joint is swollen,
red, and painful. Synovial fluid purulent (WBC > 50,000/mm3).
Gonococcal arthritis—STI that presents as either purulent arthritis (eg, knee) or triad of
polyarthralgia, tenosynovitis (eg, hand), dermatitis (eg, pustules).
septic arthritis
Arthritis without rheumatoid factor (no anti-IgG antibody). Strong association with HLA-B27
(MHC class I serotype). Subtypes (PAIR ) share variable occurrence of inflammatory back
pain (associated with morning stiffness, improves with exercise), peripheral arthritis, enthesitis
(inflamed insertion sites of tendons, eg, Achilles), dactylitis (“sausage fingers”), uveitis.
- Psoriatic arthritis
2. Ankylosing spondylitis
3. Inflammatory bowel disease
4. Reactive arthritis
Psoriatic arthritis
Associated with skin psoriasis and nail lesions.
Asymmetric and patchy involvement A .
Dactylitis and “pencil-in-cup” deformity of
DIP on x-ray (C).
Ankylosing spondylitis
Symmetric involvement of spine and sacroiliac
joints –> ankylosis (joint fusion), uveitis, aortic
regurgitation.
Bamboo spine (vertebral fusion) (C) . Can cause restrictive lung disease due to limited chest wall expansion (costovertebral and costosternal ankylosis).
More common in males.
Inflammatory bowel disease
Crohn disease and ulcerative colitis are often
associated with spondyloarthritis.
Reactive arthritis Formerly known as Reiter syndrome.
Classic triad:
.Conjunctivitis
.Urethritis
. Arthritis
Shigella, Yersinia, Chlamydia, Campylobacter,
Salmonella (ShY ChiCS).
Systemic lupus erythematosus
Systemic, remitting, and relapsing autoimmune disease. Organ damage primarily due to a type III
hypersensitivity reaction and, to a lesser degree, a type II hypersensitivity reaction. Associated with
deficiency of early complement proteins (eg, C1q, C4, C2) –> decrease clearance of of immune complexes.
Classic presentation: rash, joint pain, and fever in a female of reproductive age (especially of
African-American or Hispanic descent).
Libman-Sacks Endocarditis—nonbacterial, verrucous thrombi usually on mitral or aortic valve and can be present on either surface of the valve (but usually on undersurface). LSE in SLE.
Lupus nephritis (glomerular deposition of DNA-anti-DNA immune complexes) can be nephritic or nephrotic (causing hematuria or
proteinuria). Most common and severe type is diffuse proliferative.
Common causes of death in SLE: Renal disease
(most common)
Rash (malar A or discoid B )
Arthritis (nonerosive)
Serositis (eg, pleuritis, pericarditis)
Hematologic disorders (eg, cytopenias)
Oral/nasopharyngeal ulcers (usually painless)
Renal disease
Photosensitivity
Antinuclear antibodies
Immunologic disorder (anti-dsDNA, anti-Sm,
antiphospholipid)
Neurologic disorders (eg, seizures, psychosis)
pregnancy with positive anti-SSA can have newborn with neonatal lupus (congenital heart block, periorbital/diffusion, rash, transaminitis, cytopenias at birth
1’ or ‘ autoimmune disorder (most commonly in SLE). Diagnose based on clinical criteria including
history of thrombosis (arterial or venous) or spontaneous abortion along with
laboratory findings of lupus anticoagulant,
anticardiolipin, anti-β2 glycoprotein antibodies.
Treat with systemic anticoagulation.
lupus anticoagulant
can cause prolonged PTT that is not corrected
by the addition of normal platelet-free plasma
antiphospholipid syndrome
SYMPTOMS: Pain and stiffness in proximal muscles (eg, shoulders, hips), often with fever, malaise, weight loss.
Does not cause muscular weakness. More common in women > 50 years old; associated with
giant cell (temporal) arteritis.
FINDINGS : increased ESR, increase CRP, normal CK.
TREATMENT: Rapid response to low-dose corticosteroids
Polymyalgia rheumatic
Most common in women 20–50 years old. Chronic, widespread musculoskeletal pain associated
with “tender points,” stiffness, paresthesias, poor sleep, fatigue, cognitive disturbance (“fibro
fog”). Treatment: regular exercise, antidepressants (TCAs, SNRIs), neuropathic pain agents (eg,
gabapentin).
fibromyalgia
increased CK, ⊕ ANA (nonspecific), ⊕ anti-Jo-1 (histidyl-tRNA synthetase) (specific), ⊕ anti-SRP (specific), ⊕ anti-Mi-2 (specific) antibodies.
Both disorders associated with interstitial lung disease.
Treatment: steroids followed by long-term immunosuppressant therapy (eg, methotrexate).
Polymyositis: Progressive symmetric proximal muscle weakness, characterized by endomysial inflammation with CD8+ T cells. Most often involves shoulders.
dermatomyositis: Clinically similar to polymyositis, but also involves malar rash (similar to that in SLE but involves nasolabial folds), Gottron papules A , heliotrope (violaceous periorbital) rash B , “shawl and face” rash C , darkening and thickening of fingertips and sides resulting in irregular, “dirty”-appearing
marks.
increase risk of occult malignancy. Perimysial inflammation and atrophy with CD4+ T cells.
Myastenia gravis- most common NMJ disorder due to autoantibodies to postsynatpic ACh receptor, clinical: ptosis, diplopia, weakness (respiratory muscle involvement–> dyspnea. bulbar muscles–> dysphagia, difficulty chewing), worse with muscle use. treatment: AChE inhbitor: reverse sx
associated with thymoma, thymic hyperplasia
Lambert-Eaton myastenic syndrome-uncommon, autoantibodies to presynaptic Ca channel to lower ACh release, clinical: proximal muscle weakness, autonomic symptoms (dry mouth, impotence) improves with muscle use
AChE inhibitor have miminal effects
associated with small cell lung cancer
decreased blood flow to skin due to arteriolar (small vessel) vasospasm in response to cold or stress: color change from white (ischemia) to blue (hypoxia) to red (reperfusion). Most often in the
fingers (A) and toes. Called Raynaud disease when 1’ (idiopathic), Raynaud syndrome when 2’
to a disease process such as mixed connective tissue disease, SLE, or CREST syndrome (limited
form of systemic sclerosis). Digital ulceration (critical ischemia) seen in 2’ Raynaud syndrome.
Treat with Ca2+ channel blockers.
Raynaud phenomenon
Triad of 1. autoimmunity, 2. noninflammatory vasculopathy, and 3. collagen deposition with fibrosis.
Commonly sclerosis of skin, manifesting as puffy, taut skin (A)without wrinkles, fingertip pitting
(B). Can involve other systems, eg, renal (scleroderma renal crisis; treat with ACE inhibitors),
pulmonary (interstitial fibrosis, pulmonary HTN), GI (esophageal dysmotility and reflux),
cardiovascular. 75% female. 2 major types:
. Diffuse scleroderma —widespread skin involvement, rapid progression, early visceral
involvement. Associated with anti-Scl-70 antibody (anti-DNA topoisomerase I antibody).
. Limited scleroderma —limited skin involvement confined to fingers and face. Also with CREST syndrome: Calcinosis cutis (C) , anti-Centromere antibody, Raynaud phenomenon,
Esophageal dysmotility, Sclerodactyly, and Telangiectasia. More benign clinical course.
scleroderma
Skin has 3 layers: epidermis, dermis, subcutaneous fat (hypodermis, subcutis). Epidermis layers from surface to base A :
Stratum Corneum (keratin)
Stratum Lucidum (most prominent in palms and soles)
Stratum Granulosum
Stratum Spinosum (desmosomes)
Stratum Basale (stem cell site)
Tight junction (zonula occludens)—prevents paracellular movement of solutes; composed of claudins and occludins.
Adherens junction (belt desmosome, zonula adherens)—below tight junction, forms “belt” connecting actin cytoskeletons of adjacent cells with CADherins (Ca2+-dependent adhesion proteins ). Loss of E-cadherin promotes metastasis.
Desmosome (spot desmosome, macula adherens)—structural support via intermediate filament interactions . Autoantibodies to desmoglein pemphigus vulgaris.
Gap junction—channel proteins called connexons permit electrical and chemical communication between cells.
Integrins—membrane proteins that maintain integrity of basolateral membrane by binding to collagen, laminin, and fibronectin in basement membrane.
Hemidesmosome—connects keratin in basal cells to underlying basement membrane. Autoantibodies bullous pemphigoid. (Hemidesmosomes are down “bullow”).
macules- flat lestion with well-circumscribed change in skin color <1cm (freckles, labial macule)
patch-macules >1 cm (large birthmark (congenital nevus)
papules- elevatd solid skin lesion < 1 cm (mole (nevus), acne)
plaque - papules > 1 cm (psoriasis)
vesicle - small fluid -caintaining blister < 1 cm (chickenpox (varicella), shingles (zoster)
bulla- large fluid-contain blister > 1 cm (Bullous pemphigoid)
pustule-vesicle containing pus (pustular psoriasis)
wheal- transient smooth papules or plaque (hives (urticaria)
scale- flaking off of stratum corneum (Eczema, psoriasis, SCC)
crust- dry exudate (impetigo)
hyperkeratosis- increase thickness of stratum corneum (psoriasis, callus)
parakeratosis- retention of nuclei in stratum corneum (Psoriasis)
hypergranulosis- increased thickness of stratum granulosum (Lichen planus)
spongiosis-epidermal accumulation of edematous fluid in intercellular spacs (Eczematous dermatitis)
achantholysis-separation of epidermal cells (pemphigus vulgaris)
acanthosis- epidermal hyperplasia (increase spinosum) (acanthosis nigricans)
Normal melanocyte number with decreased melanin production due to decrease tyrosinase activity or defective tyrosine transport. increase risk of skin cancer.
albinism
Hyperpigmentation associated with pregnancy (“mask of pregnancy” B ) or OCP use
melasma
Irregular patches of complete depigmentation (C ). Caused by autoimmune destruction of melanocytes.
Vitiligo
Erythematous, well-demarcated plaques with greasy yellow scales in areas rich in sebaceous glands, such as scalp, face, and periocular region. Common in both infants and adults, associated with Parkinson disease. Sebaceous glands are not inflamed, but play a role in disease development. Possibly associated with Malassezia spp.
Treat with topical antifungals and corticosteroids.
seborrheic dermatitis
Multifactorial etiology—increased sebum/androgen production, abnormal keratinocyte desquamation, Cutibacterium (formerly Propionibacterium) acnes colonization of the pilosebaceous unit (comedones), and inflammation (papules/pustules (A), nodules, cysts).
Treatment includes retinoids, benzoyl peroxide, and antibiotics.
Acne
Pruritic eruption, commonly on skin flexures. Associated with other atopic diseases (asthma, allergic rhinitis, food allergies); increase serum IgE. Mutations in filaggrin gene predispose (via skin barrier dysfunction). Often appears on face in infancy and then in antecubital fossa in children and adults.
atopic dermatitis (eczema)
Type IV hypersensitivity reaction that follows exposure to allergen. Lesions occur at site of contact (eg, nickel, poison ivy, neomycin).
Allergic contact dermatitis
Common mole. Benign, but melanoma can arise in congenital or atypical moles. Intradermal nevi are papular. Junctional nevi are flat macules.
melanocytic nevus
Foreign body inflammatory facial skin disorder characterized by firm, hyperpigmented papules and pustules that are painful and pruritic. Located on cheeks, jawline, and neck. Commonly occurs as a result of shaving (“razor bumps”), primarily affects African-American males.
Pseudofolliculitis barbae
Papules and plaques with silvery scaling H, especially on knees and elbows. Acanthosis with parakeratotic scaling (nuclei still in stratum corneum), Munro microabscesses. increase stratum spinosum, decrease stratum granulosum. Auspitz sign ( I )—pinpoint bleeding spots from exposure of dermal papillae when scales are scraped off. Associated with nail pitting and psoriatic arthritis
Psoriasis
Inflammatory facial skin disorder characterized by erythematous papules and pustules, but no comedones. May be associated with facial flushing in response to external stimuli (eg, alcohol, heat). Phymatous rosacea can cause rhinophyma (bulbous deformation of nose).
Rosacea
Flat, greasy, pigmented squamous epithelial proliferation with keratin-filled cysts (horn cysts). Looks “stuck on.” Lesions occur on head, trunk, and extremities. Common benign neoplasm of older persons. Leser-Trélat sign (L) —sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy (eg, GI, lymphoid).
Seborrheic keratosis
Warts; caused by low-risk HPV strains. Soft, tan-colored, cauliflower-like papules (M). Epidermal hyperplasia, hyperkeratosis, koilocytosis. Condyloma acuminatum on anus or genitals (N).
Verrucae
Hives. Pruritic wheals that form after mast cell degranulation O. Characterized by superficial dermal edema and lymphatic channel dilation.
urticaria
Rare blood vessel malignancy typically occurring in the head, neck, and breast areas. Usually in elderly, on sun-exposed areas.
Associated with radiation therapy and chronic postmastectomy lymphedema. Hepatic angiosarcoma associated with vinyl chloride and arsenic exposures. Very aggressive and difficult to resect due to delay in diagnosis.
angiosarcoma
Benign capillary skin papules found in AIDS patients. Caused by Bartonella infections. Frequently mistaken for Kaposi sarcoma, but has neutrophilic infiltrate.
bacillary angiomatosis
Benign capillary hemangioma of the elderly . Does not regress. Frequency increase with age
cherry hemangioma
Cavernous lymphangioma of the neck . Associated with Turner syndrome.
Cavernous lymphangioma
Benign, painful, red-blue tumor, commonly under fingernails. Arises from modified smooth muscle cells of the thermoregulatory glomus body
glomus tumor
Endothelial malignancy most commonly of the skin, but also mouth, GI tract, and respiratory tract. Associated with HHV-8 and HIV. Rarely mistaken for bacillary angiomatosis, but has lymphocytic infiltrate.
Kaposi sarcoma
Polypoid lobulated capillary hemangioma (E) that can ulcerate and bleed. Associated with trauma and pregnancy.
Pyogenic granuloma
Very superficial skin infection. Usually from S aureus or S pyogenes. Highly contagious. Honeycolored crusting. Bullous impetigo has bullae and is usually caused by S aureus
impetigo
Infection involving upper dermis and superficial lymphatics, usually from S pyogenes. Presents with well-defined, raised demarcation between infected and normal skin.
Erysipelas
Acute, painful, spreading infection of deeper dermis and subcutaneous tissues. Usually from S pyogenes or S aureus. Often starts with a break in skin from trauma or another infection.
Abscess
Collection of pus from a walled-off infection within deeper layers of skin. Offending organism is almost always S aureus.
abscess
Deeper tissue injury, usually from anaerobic bacteria or S pyogenes. Pain may be out of proportion to exam findings. Results in crepitus from methane and CO2 production. “Flesh-eating bacteria.” Causes bullae and a purple color to the skin. Surgical emergency
Necrotizing fasciitis
Exotoxin destroys keratinocyte attachments in stratum granulosum only (vs toxic epidermal necrolysis, which destroys epidermal-dermal junction). Characterized by fever and generalized erythematous rash with sloughing of the upper layers of the epidermis that heals completely. ⊕ Nikolsky sign (separation of epidermis upon manual stroking of skin). Seen in newborns and children, adults with renal insufficiency.
Staphylococcal scaled skin syndrome
Herpes virus infections (HSV1 and HSV2) of skin can occur anywhere from mucosal surfaces to normal skin. These include herpes labialis, herpes genitalis, herpetic whitlow (H) (finger).
Herpes
Umbilicated papules single or, more often, multiple, rounded, dome-shaped, pink, waxy papules that are 2-5 mm (rarely up to 1.5 cm in the case of a giant molluscum) in diameter. contain a caseous plug.)(I) caused by a poxvirus. While frequently seen in children, it may be sexually transmitted in adults.
molluscum contagiosum
Causes varicella (chickenpox) and zoster (shingles). Varicella presents with multiple crops of lesions in various stages from vesicles to crusts. Zoster is a reactivation of the virus in dermatomal distribution (unless it is disseminated).
Varicella Zoster virus
Irregular, white, painless plaques on lateral tongue that cannot be scraped off (J) EBV mediated. Occurs in HIV-positive patients, organ transplant recipients.
Contrast with thrush (scrapable) and leukoplakia (precancerous).
Hairy leukoplakia
Potentially fatal autoimmune skin disorder with IgG antibody against desmoglein (component of desmosomes, which connect keratinocytes in the stratum spinosum). Flaccid intraepidermal bullae (A) caused by acantholysis (separation of keratinocytes, resembling a “row of tombstones”); oral mucosa is also involved. Type II hypersensitivity reaction. Immunofluorescence reveals antibodies around epidermal cells in a reticular (net-like) pattern (B). Nikolsky sign ⊕.
pemphigus vulgaris
Less severe than pemphigus vulgaris. Type II hypersensitivity reaction: involves IgG antibody against hemidesmosomes (epidermal basement membrane; antibodies are “bullow” the epidermis). Tense blisters (C) containing eosinophils affect skin but spare oral mucosa. Immunofluorescence reveals linear pattern at epidermal-dermal junction (D). Nikolsky sign ⊝.
Bullous pemphigus
Pruritic papules, vesicles, and bullae (often found on elbows) (E). Deposits of IgA at tips of dermal papillae. Associated with celiac disease. Treatment: dapsone, gluten-free diet.
Dermatitis herpetiformis
Associated with infections (eg, Mycoplasma pneumoniae, HSV), drugs (eg, sulfa drugs, β-lactams, phenytoin), cancers, autoimmune disease. Presents with multiple types of lesions—macules, papules, vesicles, target lesions (look like targets with multiple rings and dusky center showing epithelial disruption) (F).
Erythema multiforme
Characterized by fever, bullae formation and necrosis, sloughing of skin at dermal-epidermal junction, high mortality rate. Typically 2 mucous membranes are involved, and targetoid skin lesions may appear, as seen in erythema multiforme.
Usually associated with adverse drug reaction. A more severe form of Stevens-Johnson syndrome (SJS) with > 30% of the body surface area involved is toxic epidermal necrolysis (I J) (TEN). 10–30% involvement denotes SJS-TEN
Steven Johnson syndrome
Epidermal hyperplasia causing symmetric, hyperpigmented thickening of skin, especially in axilla or on neck. Associated with insulin resistance (eg, diabetes, obesity, Cushing syndrome), visceral malignancy (eg, gastric adenocarcinoma).
Acanthosis nigricans
Premalignant lesions caused by sun exposure. Small, rough, erythematous or brownish papules or plaques (C D). Risk of squamous cell carcinoma is proportional to degree of epithelial dysplasia.
Actinic keratosis
Painful, raised inflammatory lesions ofErythema Nodosum usually on anterior shin. Often idiopathic, but can be associated with sarcoidosis, coccidioidomycosis, histoplasmosis, TB, streptococcal infections (E) , leprosy (F) , inflammatory bowel disease.
Erythema Nodosum
Pruritic, Purple, Polygonal Planar Papules and Plaques are the 6 P’s of lichen Planus (G H). Mucosal involvement manifests as Wickham striae (reticular white lines) and hypergranulosis. Sawtooth infiltrate of lymphocytes at dermal-epidermal junction. Associated with hepatitis C.
Lichen planus
“Herald patch” I followed days later by other scaly erythematous plaques, often in a “Christmas tree” distribution on trunk (J). Multiple pink plaques with collarette scale. Self-resolving in 6–8 weeks.
collarette scale-Fine scaling and central wrinkling, with a cigarette paper aspect, is usually present. A characteristic feature is the collarette appearance of the scale, with edges peripherally attached and lifted up near the center of the lesion.
Pityriasis
Acute cutaneous inflammatory reaction due to excessive UV irradiation. Causes DNA mutations, inducing apoptosis of keratinocytes. UVB is dominant in sunBurn, UVA in tAnning and photoAging. Exposure to UVA and UVB
increase risk of skin cancer. Can also lead to impetigo.
sunburn
1. -superficial, through epidermis (common sunburn) (painful, erythematous, blanching)
2. (partial-thickness burn through epidermis and dermis). skin is blistered and usually heals without scarring (painful, erythematous, blanching)
3. full-thickness burn through epidermis, dermis, and hypodermis , skin scars with woud healing (painless, waxy or leathery appearance nonblanching
first degree burn
second degree burn
third degree burn
Most common skin cancer. Found in sun-exposed areas of body (eg, face). Locally invasive, but rarely metastasizes. Waxy, pink, pearly nodules, commonly with telangiectasias, rolled borders, central crusting or ulceration (A). BCCs also appear as nonhealing ulcers with infiltrating growth (B) or as a scaling plaque (superficial BCC) (C). Basal cell tumors have “palisading” nuclei (D.)
basal cell carcinoma
Second most common skin cancer. Associated with excessive exposure to sunlight, immunosuppression, chronically draining sinuses, and occasionally arsenic exposure.
Commonly appears on face (E) , lower lip (F) , ears, hands. Locally invasive, may spread to lymph nodes, and will rarely metastasize. Ulcerative red lesions with frequent scale.
Histopathology: keratin “pearls” (G).
Actinic keratosis, a scaly plaque, is a precursor to squamous cell carcinoma. Keratoacanthoma is a variant that grows rapidly (4–6 weeks) and may regress spontaneously over
squamous cell carcinoma
Common tumor with significant risk of metastasis. S-100 tumor marker. Associated with sunlight exposure and dysplastic nevi; fair-skinned persons are at increase risk.
Depth of tumor (Breslow thickness) correlates with risk of metastasis.
Look for the ABCDEs: Asymmetry, Border irregularity, Color variation, Diameter > 6 mm, and Evolution over time.
At least 4 different types of melanoma, including superficial
- spreading (I)
- nodular (J)
- lentigo maligna (K)
- acral lentiginous (highest prevalence in African-Americans and Asians) (L)
Often driven by activating mutation in BRAF kinase.
Primary treatment is excision with appropriately wide margins. Metastatic or unresectable melanoma in patients with BRAF V600E mutation may benefit from vemurafenib, a BRAF kinase inhibitor
melanoma
