Skin QandA explanations

Question 1

Robbins 4: The figure shows a _____ with _____ borders and variability of pigmentation. Any change in pigmented lesion suggests possibility of _____. Some ____ are familial, arising from conditions such as what?

Answer 1

melanoma; irregular; melanoma; melanomas, dysplastic nevus syndrome

Question 2

Robbins 7: Actinic keratoses are

Answer 2

premalignant lesions associated with sun exposure. Older individuals are more likely to have actinic keratoses because of greater cumulative sun exposure, NOT NECESSARILY aging alone

Question 3

Robbins 8: what is producing the intense pruritis in this patient?

Answer 3

Small scabies mites burrow through stratum corneum to produce linear lesions, and mites along with their eggs and feces produce intense pruritus

Question 4

Robbins 9: What is the key word here?

Answer 4

Pink cytoplasmic inclusions, called MOLLUSCUM bodies; immunocompromised individuals may have multiple, larger lesions. Infectious agent is a poxvirus

Question 5

Robbins 12: 6P’s question

Answer 5

Distinctive bandlike infiltrate of lymphocytes at dermal-epidermal junction; lesions of lichen planus typically self-limited; oral lesions may persist longer and no risk of MALIGNANCY!!

Question 6

Robbins 13: Athlete’s foot is

Answer 6

a common disorder resulting from superficial dermatophyte infection by various fungal species, including Trichophyton, Epidermophyton, Microsporium; infections involving the foot produce condition known as tinea pedis (METs play like they have Athletes foot)

Question 7

Robbins 15: If the man eats the cookies

Answer 7

he will have “hives,” or urticaria, from an allergy to antigen in the nuts; a type I hypersens reaction occurs when IgE Abs are bound to IgE receptor on mast cells, leading to degranulation when antigen is encountered

Question 8

Robbins 16: The clinical ppearance, distribution, and occurrence in two siblings here suggests

Answer 8

lesions represent dysplastic nevus syndrome. These nevi are precursors of malignant melanoma, and most important gene in familial cases is CYCLIN-DEPENDENT KINASE INHIBITOR 2 (CDNK2), which encodes for several tumor suppressors including p16/INK4A

Question 9

Robbins 25: Tinea versicolor is a

Answer 9

common condition caused by a superficial fungal infection of Malassezia furfur; lesions can be lighter or darker than the surrounding skin

Question 10

Robbins 26: Time course of this case

Answer 10

suggests a drug reaction producing an acute erythematous dermatitis

Question 11

Robbins 27: ____ is a form of panniculitis that can be associated with

Answer 11

Erythema nodosum;
infections, drug ingestion, inflammatory bowel disease, and malignancies; inflammation primarily involves DERMAL ADIPOSE TISSUE

Question 12

Robbins 28: What is the most common form of epithelial cyst. This is a

Answer 12

Epidermal inclusion cyst;
cystic structure formed from downward growth of epi or expansion of a hair follicle and is lined by squamous epi that desquamates keratinaceous debris in the center of the expnading cyst. Ruputre produces local inflamm rxn.

Question 13

Robbins 29: This patient has

Answer 13

urticaria pigmentosa, a localized form of mastocytosis; cutaneous lesions often show the characteristic Darier sign on rubbing, some perhaps systemic mastiocytosis, and maybe point mutations in C-KIT oncogene present

Question 14

Robbins 30: ____ also known as

Answer 14

an acrochordon or skin tag; these common lesions are composed of a central core of fibrovascular CT covered by normal-appearing squamous epi. They may become irritated, but are otherwise incidental findings

Question 15

Robbins 31: The figure shows

Answer 15

a form of nevocellular nevus known as a congenital nevus

Question 16

Rubin’s 1: Sudden appearance of numerous _____ has been associated with

Answer 16

seborrheic keratoses; internal malignancies (sign of Leser-Trelat), especially gastric adenocarcinoma

Question 17

Rubin’s 2: Germline mutation in the what gene has been found in some patients who have

Answer 17

CDKN2A tumor suppressor gene (aka p16); dysplastic nevus/melanoma

Question 18

Rubin’s 3: Actinic keratoses

Answer 18

develop in sun-damaged skin as circumscribed keratotic patches or plaques, commonly on backs of hands or face; stratum corneum replaced by dense parakeratotic scale, underlycing basal keratinocytes have significant atypia, and these AK’s could develop into ultimate invasive squamous cell

Question 19

Rubin’s 4: Kaposi sarcoma is a

Answer 19

malignant tumor derived from endothelial cells; important cutaneous sign in the AIDS pandemic; HHV-8 thought to play a role in Kaposi sarcoma pathogenesis; histologic appearance of sarcoma is highly variable, either resembling simple capillary hemagioma or could be highly cellular and vascular spaces less prominent

Question 20

Rubin’s 6: Ichthyosis vulgaris is an

Answer 20

autosomal dominant disorder of keratinization characterized by mild hyperkeratosis and reduced or absent keratohyaline granules in the episdermis. Scaly skin results from increased stratum corneum cohesiveness. Use topical treatments.

Question 21

Rubin’s 7: Lentigo maligna melanoma is

Answer 21

a large, pigmented macule that occurs on sun-damaged skin; it develops almost exclusively in fair-skinned usually elderly whites; talking about UV light exposure; acral lentiginous melanoma is the most common form of melanoma in dark-skinned people is generally is limited to palms, soles, and subungual regions, while mucosal lentiginous melanoma is mucous membranes!!

Question 22

Rubin’s 12: Verruca vulgaris

Answer 22

is an elevated papule with verrucous surface; warts might be single or multiple and are most frequent on the dorsal surfaces of the hands or face

Question 23

Rubin’s 13: EN is a

Answer 23

cutaneous disorder that manifests as self-limited, nonsuppurative, tender nodules over extensor surfaces of lower extremities; triggered by exposure to agents, like drugs and microorganisms; early neutrophilic inflammation suggests that EN may be a response to activation of complement with resulting neutrophilic chemotaxis

Question 24

Rubin’s 19: Mycosis fungoides

Answer 24

is a variant of cutanoues T-cell lymphoma; look for lymphocytes in the epidermis; in late stages, the dermal infiltrate becomes dense to the point of forming tumor nodules

Question 25

Rubin’s Cutanoues necrotizing vasculitis

Answer 25

presents as palpable purpura and also called allergic cutaneous vasculitis, leukocytoclastic vasculitis, and hypersens angiitis; you see immune complexes deposited in vascular walls and C5a complement compnent attracts neutrophils, which degranulate and release lysosomal enzymes, resulting in endothelial damage and fibrin deposition; can be associated with specific infectious agent or chronic disease like Hep B and ulcerative colitis, respectively