U2-Robbins-C25: Skin Flashcards
For the past decade, a 29-year-old man has had waxing and waning of the lesions shown in the figure. The scalp,
lumbosacral region, and glans penis also are affected. For the past 2 years, he has had chronic arthritis in the hips and
knees. Which of the following physical findings would most likely be present in this patient?
□ (A) Guaiac-positive stool
□ (B) Friction rub
□ (C) Hyperreflexia
□ (D) Damage to the nails
□ (E) Hypertension
(D) This patient has psoriasis, a chronic skin condition with marked epithelial hyperplasia and parakeratotic scaling. Nail
changes, such as yellow-brown discoloration, pitting, dimpling, and separation of the nail plate from the nail bed
(onycholysis) , affect about one third of patients. Other manifestations of psoriasis include arthritis (resembling rheumatoid
arthritis) , myopathy, enteropathy, and spondylitic heart disease. Gastrointestinal mucosal involvement with hemorrhage is
not a feature of psoriasis. A friction rub from fibrinous pericarditis does not occur in psoriasis because mesothelial surfaces
are not involved. Joint laxity with hyperreflexia is a feature of Ehlers-Danlos syndrome. Renal disease and hypertension
are not typically the result of psoriasis.
An epidemiologic study is conducted to identify factors that increase the risk of skin cancer. The study documents
subjects reported to tumor registries with a diagnosis of malignant melanoma and the incidence of melanoma worldwide
over the past 25 years. Demographic information is collected. Analysis of the data is most likely to show the greatest
increase in incidence of malignant melanoma in which of the following locations?
□ (A) Edinburgh, Scotland
□ (B) Cairo, Egypt
□ (C) Brisbane, Australia
□ (D) Tahiti, French Polynesia
□ (E) Hong Kong, China
(C) The driving force behind a worldwide rise in melanoma has been increased sun exposure. The Australian population
is mainly derived from light-skinned Europeans who migrated to Australia. Indigenous, dark-skinned populations do not
have the same risk.
A 64-year-old man has noted changes in the texture and color of skin in his armpit and groin over the past 3 months. On
physical examination, there is thickened, darkly pigmented skin in the axillae and flexural areas of the neck and groin.
These areas are neither painful nor pruritic. A punch biopsy specimen of axillary skin shows undulating epidermal
acanthosis with hyperkeratosis and basal layer hyperpigmentation. Which of the following underlying diseases is most
likely to be present in this patient?
□ (A) Systemic lupus erythematosus
□ (B) Mastocytosis
□ (C) AIDS
□ (D) Colonic adenocarcinoma
□ (E) Langerhans cell histiocytosis
(D) The patient has findings typical of acanthosis nigricans, a cutaneous marker for benign and malignant neoplasms.
The skin lesions often precede signs and symptoms of associated cancers. They are believed to arise from the action of
epidermal growth-promoting factors produced by neoplasms. The rashes that develop in systemic lupus erythematosus
are the result of antigen-antibody complex deposition and often exhibit photosensitivity. Skin lesions of mastocytosis in
Robbins & Cotran Review of Pathology Pg. 524
adults often exhibit urticaria. Various skin lesions are associated with AIDS, including disseminated infections and
papulosquamous dermatoses, although not pigmented lesions. Involvement of the skin in Langerhans cell histiocytoses
typically occurs in children and produces reddish papules or nodules or erythematous scaling plaques because of the
histiocytic infiltrates in the dermis.
A 51-year-old man noticed a change in the skin lesion on the upper, outer area of his right arm, shown in the figure. The
lesion has enlarged during the past month. Physical examination yields no other remarkable findings. Which of the
following occupations is this man most likely to have had earlier in life?
□ (A) Chemist
□ (B) Lifeguard
□ (C) Miner
□ (D) Auto mechanic
□ (E) Radiation oncologist
(B) The figure shows a malignant melanoma with irregular borders and variability of pigmentation. Any change in a
pigmented lesion suggests the possibility of melanoma. Some melanomas are familial, arising from conditions such as
dysplastic nevus syndrome. Most melanomas occur sporadically, however, and are related to sun exposure, as may occur
in a lifeguard.
A 35-year-old man has had an outbreak of pruritic lesions over the extensor surfaces of the elbows and knees during the
past month. He has a history of malabsorption that requires him to eat a special diet, but he has had no previous skin
problems. On physical examination, the lesions are 0.4- to 0.7-cm vesicles. A 3-mm punch biopsy of one of the lesions
over the elbow is performed. Microscopic examination of the biopsy specimen shows accumulation of neutrophils at the
tips of dermal papillae and formation of small blisters owing to separation at the dermoepidermal junction.
Immunofluorescence studies performed on this specimen show granular deposits of IgA localized to tips of dermal papillae.
Laboratory studies show serum antigliadin antibodies. What is the most likely diagnosis?
□ (A) Bullous pemphigoid
□ (B) Contact dermatitis
□ (C) Dermatitis herpetiformis
□ (D) Discoid lupus erythematosus
□ (E) Erythema multiforme
□ (F) Impetigo
□ (G) Lichen planus
□ (H) Pemphigus vulgaris
(C) The clinical and histologic findings are typical of celiac disease with dermatitis herpetiformis. The IgA or IgG
antibodies formed against the gliadin protein in gluten that is ingested cross-react with reticulin. Reticulin is a component
of the anchoring fibrils that attach the epidermal basement membrane to the superficial dermis. This explains the
localization of the IgA to the tips of dermal papillae and the site of inflammation. A gluten-free diet may relieve the
symptoms. Bullous pemphigoid can occur in older individuals, with antibody directed at keratinocytes to produce flaccid
bullae, but there is no association with celiac disease. Contact dermatitis is most likely to be seen on the hands and
forearms. It is a type IV hypersensitivity reaction without immunoglobulin deposition and would not persist for 1 month.
Discoid lupus erythematosus is seen on sun-exposed areas and has the appearance of an erythematous rash. Erythema
multiforme is a hypersensitivity response to infections and drugs; it produces macules and papules with a red or vesicular
center, but it is probably mediated by cytotoxic lymphocytes and not by immunoglobulin deposition. Impetigo produced by
infection with staphylococci and streptococci produces pustules and crusts, mainly on the hands and face. Lichen planus
appears as violaceous papules and plaques. Pemphigus vulgaris is an autoimmune disease in which IgG deposited in
acantholytic areas forms vesicles that rupture to form erosions; it is not related to celiac disease
Over the course of 1 week, a 6-year-old boy develops 1- to 2-cm erythematous macules and 0.5- to 1-cm pustules on his
face. During the next 2 days, some of the pustules break, forming shallow erosions covered by a honey-colored crust. New
lesions form around the crust. The boy’s 40-year-old uncle develops similar lesions after visiting for 1 week during the
child’s illness. Removal of the crusts from the boy’s face is followed by healing within 1 week. The uncle does not seek
medical care, and additional pustules form at the periphery of the crusts. Which of the following conditions most likely
explains these findings?
□ (A) Acne vulgaris
□ (B) Bullous pemphigoid
□ (C) Contact dermatitis
□ (D) Erythema multiforme
□ (E) Impetigo
□ (F) Lichen planus
□ (G) Pemphigus vulgaris
□ (H) Psoriasis
(E) Impetigo is a superficial infection of skin that produces shallow erosions. These erosions are covered with exuded
serum that dries to give the characteristic honey-colored crust. Cultures of the lesions of impetigo usually grow coagulasepositive
Staphylococcus aureus or group A β-hemolytic streptococcus. The lesions are highly infectious. Acne vulgaris is
typically seen during adolescence and produces pimples and pustules, but not crusts. Bullous pemphigoid can occur in
older individuals with antibody directed at keratinocytes to produce flaccid bullae. Contact dermatitis is most likely to be
seen on the hands and forearms. Erythema multiforme is a hypersensitivity response to infections and drugs that produces
macules and papules with a red or vesicular center. Lichen planus appears as violaceous papules and plaques.
Pemphigus vulgaris is an autoimmune disease in which IgG deposited in acantholytic areas forms vesicles that rupture to
form erosions. Psoriasis produces patches of silvery, scaling lesions.
A 50-year-old woman has been bothered by a discolored area of skin on her forehead that has not faded during the past
3 years. On physical examination, there is a 0.8-cm red, rough-surfaced lesion on the right forehead above the eyebrow. A
biopsy specimen examined microscopically shows basal cell hyperplasia. Some of the basal cells show nuclear atypia
associated with marked hyperkeratosis and parakeratosis with thinning of the epidermis. The upper dermal collagen and
elastic fibers show homogenization with elastosis. What is the most appropriate advice to give this patient?
□ (A) Reduce intake of dietary fat
□ (B) Wear a hat outdoors
□ (C) Stop taking aspirin for headaches
□ (D) Apply hydrocortisone cream to your face
□ (E) This condition is related to aging
(B) Actinic keratoses are premalignant lesions associated with sun exposure. Decreasing dietary fat is always a good
idea, but it does not have much effect on the skin of the face. Many drugs can cause acute eczematous dermatitis and
erythema multiforme. Hydrocortisone can alleviate the symptoms of many dermatologic conditions, but it cannot reverse
actinic damage. Older individuals are more likely to have actinic keratoses because of greater cumulative sun exposure,
not because of aging alone.
A 10-year-old girl is brought to the physician by her mother because multiple excoriations have appeared on the skin of
her hands over the past week. The child reports that she scratches her hands because they itch. Physical examination
shows several 0.2- to 0.6-cm linear streaks in the interdigital regions. Treatment with a topical lindane lotion resolves the
condition. Which of the following organisms is most likely responsible for these findings?
□ (A) Ixodes scapularis
□ (B) Tinea corporis
□ (C) Staphylococcus aureus
□ (D) Molluscum contagiosum
□ (E) Sarcoptes scabiei
(E) The small scabies mites burrow through the stratum corneum to produce the linear lesions, and the mites along with
their eggs and feces produce intense pruritus. Scabies is easily transmitted by contact and typically occurs in community
outbreaks. Ixodes scapularis is the tick that is the vector for Borrelia burgdorferi organisms, which cause Lyme disease
and erythema chronicum migrans. Tinea corporis is a superficial fungal infection that can produce erythema and crusting.
The erythematous macules and pustules of impetigo in children are often caused by staphylococcal and group A
streptococcal infection. Molluscum contagiosum is a poxvirus that produces a localized, firm nodule.
A 35-year-old man has noted a bump on his upper trunk for the past 6 weeks. On physical examination, there is a
solitary, 0.4-cm, flesh-colored nodule on the upper trunk. The dome-shaped lesion is umbilicated, and a curdlike material
can be expressed from the center. This material is smeared on a slide, and Giemsa stain shows many pink, homogeneous,
cytoplasmic inclusions. The lesion regresses over the next 2 months. Which of the following infectious agents most likely
produced this lesion?
□ (A) Human papillomavirus
□ (B) Staphylococcus aureus
□ (C) Molluscum contagiosum
□ (D) Histoplasma capsulatum
□ (E) Varicella-zoster virus
(C) The pink cytoplasmic inclusions, called molluscum bodies, are characteristic of this lesion. Immunocompromised
individuals may have multiple, larger lesions. The infectious agent is a poxvirus. Human papillomavirus (not a toad) is
Robbins & Cotran Review of Pathology Pg. 525
implicated in the appearance of verruca vulgaris, or the common wart. Staphylococcus aureus is implicated in the
formation of the lesions of impetigo. Disseminated fungal infections are uncommon except in immunocompromised
patients. Varicella-zoster virus causes shingles, characterized by a dermatomal distribution of clear, painful vesicles.
Many skin disorders give rise to vesicles or bullae (blisters) in the skin. The location of the bulla often aids in the
diagnosis. What disorder is most likely to produce the type of blister that is schematically illustrated in the figure?
Robbins & Cotran Review of Pathology Pg. 516
□ (A) Impetigo
□ (B) Pemphigus vulgaris
□ (C) Bullous pemphigoid
□ (D) Acute eczematous dermatitis
□ (E) Urticaria
(C) The figure shows a subepidermal bulla of bullous pemphigoid, which usually heals without scarring. Subsequent
oral lesions may appear. Most often seen in the elderly, this disease results from linear IgG deposition at the basal
cellbasement membrane attachment plaques (hemidesmosomes) containing bullous pemphigoid antigen (BPAG). In
contrast, the antibodies in pemphigus vulgaris attack the desmosomes that attach the epidermal keratinocytes. Loosening
of these junctions leads to acantholysis, and an intraepidermal blister is formed just above the basal layer (suprabasal). In
impetigo, there is infection of the superficial layer of the skin, and the blister is just under the stratum corneum
(subcorneal). Acute eczematous dermatitis has spongiotic vesicles, not bullae. In urticaria, the allergic reaction causes
increased vascular permeability in dermal capillaries. This produces superficial dermal edema, not a bulla.
A 39-year-old woman has a nodule on her back that has become larger over the past 2 months. On physical
examination, there is a 2.1-cm pigmented lesion with irregular borders and an irregular brown-to-black color. An excisional
biopsy with wide margins is performed, and microscopic examination of the biopsy specimen shows a malignant melanoma
composed of epithelioid cells that extends 2 mm down to the reticular dermis. There is a band of lymphocytes beneath the
melanoma. Which of the following statements is most appropriate to make to this patient regarding these findings?
□ (A) Your immune system will prevent metastases
□ (B) The prognosis is poor
□ (C) Other family members are at risk for this condition
□ (D) The primary site for this lesion is probably the eye
□ (E) Nevi elsewhere on your body may become malignant
(B) Extension deep into the reticular dermis indicates vertical (nodular) growth. When a melanoma exhibits a nodular
growth pattern, rather than a radial pattern, there is increased likelihood that a clone of neoplastic cells has arisen that is
more aggressive and is more likely to metastasize. Although there has been a lymphocytic response to this tumor, it is
insufficient to destroy or contain it completely. Most melanomas are sporadic, nonfamilial, and related to sun exposure.
Melanomas of the eye are much less common than melanomas of the skin. Benign skin nevi do not have a tendency to
become malignant.
A 39-year-old woman goes to her dentist for a routine checkup. The dentist notes that she has 0.2- to 1.5-cm scattered,
white, reticulated areas on the buccal mucosa. The woman says that these lesions have been present for 1 year. She also
has some 0.3-cm purple, pruritic papules on each elbow. A biopsy specimen of a skin lesion shows a bandlike infiltrate of
lymphocytes at the dermal-epidermal junction and degeneration of basal keratinocytes. What is the best advice to give this
patient regarding these lesions?
□ (A) A squamous cell carcinoma is likely to develop
□ (B) You may develop chronic renal disease
□ (C) A skin test for tuberculosis needs to be performed
□ (D) You should stop taking all medications
□ (E) These lesions will probably resolve over time
(E) This patient has the classic “pruritic, purple, polygonal papules” of lichen planus, with the distinctive bandlike
infiltrate of lymphocytes at the dermal-epidermal junction. The lesions of lichen planus are typically self-limited, although
the course can run for several years. Oral lesions may persist longer. There is no risk of malignancy. Although a
lymphocytic infiltrate is present, an infection or autoimmunity is not implicated. A drug eruption would not last this long.
Lesions of erythema multiforme are more likely to follow infections, drugs, autoimmune diseases, and malignancies.
A 22-year-old man and other members of his racquetball club have noticed more itching of their feet in the past 2
months. On physical examination, the man has diffuse, erythematous, scaling skin lesions between the toes of both feet.
There are no other remarkable findings. These findings are most likely the result of infection with which of the following
organisms?
□ (A) Borrelia burgdorferi
□ (B) Group A β-hemolytic streptococcus
□ (C) Herpes simplex virus
□ (D) Varicella-zoster virus
□ (E) Human papillomavirus
□ (F) Molluscum contagiosum
□ (G) Propionibacterium acnes
□ (H) Sarcoptes scabiei
□ (I) Staphylococcus aureus
□ (J) Trichophyton rubrum
(J) Athlete’s foot is a common disorder resulting from superficial dermatophyte infection by various fungal species,
including Trichophyton, Epidermophyton, and Microsporum. Infections that involve the foot produce the condition known
as tinea pedis. Borrelia burgdorferi causes Lyme disease, which may include a skin lesion called erythema chronicum
migrans around the original tick bite. Streptococcal and staphylococcal organisms cause impetigo, which is more common
on the face and hands. Herpetic infections first produce crops of clear vesicles, which may burst and form painful shallow
ulcers. Varicella-zoster virus is the reactivation, in adults, of childhood chickenpox in the form of vesicles in a dermatomal
distribution of the nerve in whose ganglion the virus lay dormant for years. Human papillomavirus is best known as the
cause of genital warts (condyloma acuminatum) and as a driving force behind cervical and anal squamous cell dysplasias.
Molluscum contagiosum is caused by a poxvirus and produces an umbilicated nodule. Propionibacterium acnes is a factor
in the development of acne. The little eight-legged critters known as Sarcoptes scabiei crawl around in the stratum
corneum, usually between the fingers, and cause itching, a process called scabies.
Over the past 20 years, a 75-year-old man has noticed slowly enlarging lesions, similar to those shown in the figure, on
his trunk. One of the lesions is excised, and microscopic examination shows sheets of lightly pigmented basaloid cells that
surround keratin-filled cysts. This lesion is sharply demarcated from the surrounding epidermis. What is the most likely
diagnosis?
□ (A) Basal cell carcinoma
□ (B) Condyloma acuminatum
□ (C) Intradermal nevus
□ (D) Keratoacanthoma
□ (E) Melanoma
□ (F) Seborrheic keratosis
□ (G) Squamous cell carcinoma
□ (H) Verruca vulgaris
(F) These flat, round, pigmented, sharply demarcated lesions are benign tumors called seborrheic keratoses. They are
composed of pigmented basaloid cells. Seborrheic keratoses are common in older individuals. The lesions gradually
enlarge, but they are not painful and do not ulcerate. They mainly are a cosmetic problem. Basal cell carcinomas are
nodular, slowly enlarging lesions most common on the head and trunk and are related to sun exposure. Condylomata
acuminata, or genital warts, are caused by a sexually transmitted type of human papillomavirus; the lesions tend to be pink
to white. An intradermal nevus can produce a pigmented nodule, but microscopically it is composed of nests of small
nevus cells, and the lesions increase minimally in size over time. Keratoacanthoma may resemble squamous cell
carcinoma and grow rapidly to form an ulcerative nodule, but typically regresses in several months; squamous cell
carcinoma continues to grow. Melanomas have very atypical spindle to epithelioid cells that invade the dermis; they tend
to change in appearance over weeks to months, not years. A verruca vulgaris, or wart, also has a rough surface, but such
lesions are more common on the hands and feet, and they may regress after several years. The cells in a squamous cell
carcinoma are atypical and may invade the dermis.
A 30-year-old man is known for his large appetite. At a luncheon meeting, he notices that all the cookies contain nuts,
which the other diners have ordered knowing that he would not eat them because he would develop blotchy erythematous,
slightly edematous, pruritic plaques on his skin. These plaques would form and then fade within 2 hours. If the man eats
the cookies, which of the following sensitized cells would release a mediator that produces these skin lesions?
□ (A) Mast cell
□ (B) Neutrophil
□ (C) Natural killer cell
□ (D) CD4+ lymphocyte
□ (E) Plasma cells
(A) If the man eats the cookies, he will have “hives,” or urticaria, from an allergy to an antigen in nuts. This causes a
type I hypersensitivity reaction in which IgE antibodies are bound to the IgE receptor on mast cells. IgE-sensitized mast
cells degranulate when the antigen is encountered. Neutrophils may become attracted to this site, but they are not the
sensitized cells. Natural killer cells mediate antibody-dependent cell-mediated cytotoxicity and lyse major histocompatibility
complex class I–deficient target cells. Plasma cells secrete the IgE antibodies, but do not release the mediators for allergic
reactions
A 68-year-old man visits the physician because of a slowly enlarging nodule on his right eyelid. On physical
examination, there is a 0.3-cm pearly nodule on the upper eyelid near the lateral limbus of the right eye. The lesion is
excised, but multiple frozen sections are made during the surgery to minimize the extent of the resection and preserve the
eyelid. The microscopic appearance of the lesion is shown at low magnification in the figure. What is the most likely
diagnosis?
□ (A) Malignant melanoma
□ (B) Dermatofibroma
□ (C) Actinic keratosis
□ (D) Nevocellular nevus
□ (E) Basal cell carcinoma
(E) Basal cell carcinomas arise as pearly papules on sun-exposed areas of the skin, particularly the face. They slowly
infiltrate surrounding tissues, gradually enlarging. Although it rarely metastasizes, a basal cell carcinoma can have serious
local effects, particularly in the area of the eye. Melanomas are usually pigmented, and they are composed of polygonal or
spindle cells that tend to grow in sheets and infiltrate to produce a grossly irregular border to the lesion. A dermatofibroma
is a benign lesion of the dermis composed of cells resembling fibroblasts. An actinic keratosis is a premalignant lesion of
the epidermis that does not invade surrounding tissue. A nevus is a small, localized, benign lesion.
21 A 53-year-old man with idiopathic dilated cardiomyopathy underwent orthotopic heart transplantation. During the next 5
years, he had two episodes of minimal cellular rejection, which were adequately treated by an increase in
immunosuppressive therapy. He has developed multiple skin lesions on the face and upper trunk over the past 6 months.
On physical examination, the lesions are similar to the lesion shown in the figure. Some of the larger lesions have
ulcerated. A biopsy specimen is most likely to identify which of the following lesions?
□ (A) Psoriasis
□ (B) Lichen planus
□ (C) Dermatofibroma
□ (D) Squamous cell carcinoma
□ (E) Erythema multiforme
(D) Risk factors for squamous cell carcinoma include ultraviolet light exposure, scarring from burn injury, irradiation, and immunosuppression. This patient was immunosuppressed to prevent graft rejection. Squamous cell carcinomas also
arise in rare disorders of DNA repair, such as xeroderma pigmentosum. Psoriasis is an inflammatory dermatosis that can
be associated with underlying arthritis, myopathy, enteropathy, or spondylitic heart disease. Lichen planus is a self-limited
inflammatory disorder that manifests as “purple, pruritic, polygonal papules,” not as elevated ulcerated lesions. A
dermatofibroma is typically solitary, firm, and dermally located. Erythema multiforme is a hypersensitivity response to
infections or drugs; the lesions have multiple forms, including papules, macules, vesicles, and bullae
A 28-year-old man has noticed slowly enlarging lesions on his hands for the past 3 years. On physical examination, the
lesions appear similar to those shown in the figure. There are no other remarkable findings. The lesions have not changed
in color, do not itch or bleed, and are not associated with pain. What is the most likely diagnosis?
□ (A) Basal cell carcinoma
□ (B) Condyloma acuminatum
□ (C) Dermatofibroma
□ (D) Intradermal nevus
□ (E) Keratoacanthoma
□ (F) Molluscum contagiosum
□ (G) Seborrheic keratosis
□ (H) Squamous cell carcinoma
□ (I) Verruca vulgaris
(I) The warts in this patient are a common problem and result from infection with one of many types of human
papillomavirus (HPV). They do not become malignant and tend to regress after several years. Basal cell carcinomas are
nodular, slowly enlarging lesions usually seen on the head and trunk and are related to sun exposure. Condylomata
acuminata, or genital warts, are caused by a type of HPV that is sexually transmitted; the lesions tend to be pink to white.
A dermatofibroma forms a subcutaneous nodule, as does an intradermal nevus. A keratoacanthoma may resemble
squamous cell carcinoma and grow rapidly to form an ulcerative nodule, but the keratoacanthoma typically regresses in
several months; squamous cell carcinoma continues to grow. Likewise, molluscum contagiosum is a self-limited condition
with a nodular appearance. Seborrheic keratoses are pale brown to dark brown, slowly enlarging lesions with a rough
surface that are most commonly found on the trunk and face of older individuals
A 10-year-old girl is brought to the physician by her parents because of an earache. On physical examination, the
physician notices a flat, uniformly brown, 2-cm skin lesion, just above the right buttock. Her parents state that the lesion
has been present since birth and has not changed in appearance. The figure shows the representative microscopic
appearance of the lesion. What is the most likely diagnosis of this lesion?
□ (A) Acanthosis nigricans
□ (B) Basal cell carcinoma
□ (C) Dysplastic nevus
□ (D) Lentigo
□ (E) Malignant melanoma
□ (F) Nevocellular nevus
□ (G) Seborrheic keratosis
(F) The figure shows a form of nevocellular nevus known as a congenital nevus. Larger nevi do have an increased risk
of melanoma arising within them; however, the lack of additional lesions and the bland microscopic appearance argue
against dysplastic nevus syndrome. Acanthosis nigricans is an uncommon condition with hyperpigmented areas in
skinfolds; it may occur in association with endocrinopathies or with neoplasms. Basal cell carcinomas occur in sunexposed
skin of adults, and the cells have darker nuclei with scant cytoplasm. A lentigo is a common focal pigmented
lesion that can appear at any age; it is a melanocyte hyperplasia. Melanoma occurs in adults and shows signs of rapid
growth and change, with very atypical cells invading the dermis. Seborrheic keratoses are seen in older adults and are
raised, pigmented lesions of thickened epidermis.
