Lecture 8: Skin + Musculoskeletal Disorders

Question 1

3 parts of normal skin

Answer 1

1. Epidermis
2. Dermis
3. Adnexae

Question 2

Macule

Answer 2

Flat

Question 3

Papule

Answer 3

Elevated <5 mm

Question 4

Nodule

Answer 4

Elevated >5 mm

Question 5

Vesicle

Answer 5

Fluid filled <5 mm

Question 6

Bulla

Answer 6

Fluid filled >5 mm

Question 7

Acanthosis

Answer 7

Diffuse epidermal hyperplasia

Question 8

Hyperkeratosis

Answer 8

Stratum corneum hyperplasia

Question 9

Lentiginous

Answer 9

Epidermal basal layer linear melanocyte proliferation

Question 10

Spongiosis

Answer 10

Epidermis IC edema

Question 11

Eczematous dermatitis

Answer 11

• Red papulovesicular oozing, white crusted lesions, scaly plaques
• Subtypes: contact, atopic, drug-related, photosens., primary irritant
• Spongiosis -> scaly acanthotic
• Usually cubital

Question 12

Pathogenesis of eczema

Answer 12

Sensitized T cells (init. Langerhans cells APC) release cytokines on re-exposure

Question 13

Psoriasis

Answer 13

Multifactorial immune disease of T cell sensitization -> keratinocyte hyperproliferation
- Usually antecubital

Question 14

Infectious dermatoses

Answer 14

• Bacterial, fungal, viral; non-specific epidermal alterations
• Gram stain for bacteria, PAS/silver stain for fungi

Question 15

Verrucae (warts)

Answer 15

Caused by Human Papilloma Virus; pre-neoplastic in anogenital region

Question 16

Pemphigus vulgaris

Answer 16

Autoimmune type II HSR (Ab); most common blistering disorder

Question 17

Seborrheic keratosis

Answer 17

• Round, flat, coin-like plaques
• Exophytic basal cell proliferation w/ horn cysts

Question 18

Actinic keratosis

Answer 18

• Caused by chronic sun exposure, can evolve to SCC
• Dysplastic changes (small tan-brown, rough)

Question 19

Squamous Cell Carcinoma

Answer 19

SCC invasion thru basement in sun-exposed sites

Question 20

Basal Cell Carcinoma

Answer 20

Slow growing, rarely mets.
- Pearly palisading papules in sun exposed areas

Question 21

Melanocytic nevi

Answer 21

• Benign melanocyte-derived neoplasm
• Progressive growth from dermoepidermal junction to dermis
• Small, pigmented papules
• Dysplastic nevus = melanoma precursor

Question 22

Melanoma

Answer 22

• CDKN2A germline mutation
• BRAF/NRAS proto-oncogene somatic mutations
• PTEN LOF
• Vertical + horizontal (radial) growth phases; vertical determines biologic behavior, mets.

Question 23

Osteoporosis

Answer 23

Loss of bone mass due to genes, nutrition, aging, activity

Question 24

Arthritis types

Answer 24

• Osteoarthritis
• Rheumatoid arthritis
• Gout/pseudogout
• Infectious arthritis

Question 25

Joint tumors

Answer 25

• Ganglion + synovial cysts
• Tenosynovial giant cell tumor (diffuse, local)

Question 26

Osteoarthritis

Answer 26

• Articular cartilage degeneration, fibrillation, eburnation
• Cysts, osteophytes

Question 27

Rheumatoid arthritis

Answer 27

Type IV hypersensitivity; CD4+ T cell mediated inflammation of synovial tissue vs rheumatoid factor

Question 28

Adipose tissue tumors

Answer 28

• Lipoma (benign, most common soft-tissue tumor)
• Liposarcoma (malignant)

Question 29

Fibrous tumors/tumor-like lesions

Answer 29

• Reactive proliferations
• Fibromatoses (benign, recurring, no mets.)
• Fibrosarcoma (malignant, mets.)

Question 30

Fibrohistiocytic tumors

Answer 30

• Dermatofibroma
• Pleiomorphic fibroblastic/undifferentiated sarcomas

Question 31

Rhabdomyosarcoma

Answer 31

Sk. muscle tumor; most common in kids/adolescents

Question 32

Leiomyoma

Answer 32

Benign sm. muscle tumor

Question 33

Leiomyosarcoma

Answer 33

Malignant sm. muscle tumor

Question 34

Synovial sarcoma

Answer 34

• Derived from joint cavity mesenchymal cells
• Unique t(x;18) chromosome translocation
• Epithelial + stromal components