Please note: this handout is a supplement to the most valuable part of the lecture – the

clinical photographs and histologic photomicrographs. Hope you enjoy the show!
 
 

Basal Cell Carcinoma: clinical

• most common human cancer: more than 400,000 new patients annually
• found most commonly on sun-exposed areas of fair-skinned, sun-damaged individuals
• translucent, "pearly" or "waxy" papule; associated telangiectasia, sometimes central ulceration
• locally destructive, very rarely metastasizes; can cause death
• sun-exposure, ionizing radiation, immunosuppression are all predisposing factors
• several clinical and histologic subtypes

Basal Cell Carcinoma: histology

• proliferation of atypical basal cells (large, oval, deep-blue staining, but with little anaplasia and infrequent mitoses)
• "peripheral palisading" – outermost layer of cells "line up"
• often clefts between tumor and dermis

• malignant tumor of epithelial keratinocytes – skin and mucous membranes
• induced by various carcinogens, but in the skin SUN EXPOSURE is the most common
• ionizing radiation, oncogenic viruses such as certain wart viruses, arsenic ingestion, chronic wounds also induced cutaneous SCC
• usually arises as solitary, keratotic or eroded, pink papule or nodule – persists and grows
• may arise from a precancerous actinic keratosis
• SCC arising in sun-damaged skin less prone to metastasis than mucosal SCC

Squamous Cell Carcinoma: histology

• irregular masses of tumor cells proliferate from the epidermis down into the dermis
• composed in varying proportions of normal-appearing squamous cells and atypical squamous cells
• differentiation is in the direction of keratinization
• ranges from well to poorly differentiated

• a proliferation of markedly atypical melanocytes with the potential for dermal invasion and widespread metastasis
• several clinical subtypes have been described, but the prognosis for all subtypes depends on the histologic thickness (Breslow level) of the tumor
• sun exposure is an important predisposing factor, but not as clearly causative as in the base for BCC and SCC.
• most lesions arise de novo, but some arise from "precursor lesions" such as large congenital nevi or "dysplastic" nevi

A, B, Cs of Melanoma:

• Asymmetry of shape: one half does not look like the other
• Border is irregular: scalloped, notched, discontinuous
• Color is uneven: multiple shades ranging from white to tan to brown to black occasionally some red as well
• Diameter is larger than 6mm in most cases
• Enlargement: gradual increase in size and elevation

• a clinical and histologic subtype of melanoma that occurs in sun-exposed areas (usually face) of elderly persons. Lentigo maligna is the "in situ" lesion, after dermal invasion, it is a lentigo maligna melanoma
• lentigo maligna is macular (flat), and shows all the A, B, C, Ds of melanoma; grows slowly for years before invasion; prognosis excellent before invasion
• the invasive lesions (lentigo maligna melanoma) develops a papular (palpable) component

• found almost exclusively in white-skinned persons
• most common form of melanoma
• incidence rapidly increasing, especially in young urban professionals (intense, intermittent SUN EXPOSURE)

• less common in whites than superficial spreading type but more common in Japanese
• tends to grow "up" rather than spread outward, so has a worse prognosis
• A,B,Cs less helpful here: may be symmetrical and may have uniform black color

• arises on sole, palm, fingernail or toenail bed, or the mucocutaneous skin of mouth, genitalia or anus
• most common form of melanoma in African-Americans and Japanese, groups that are not as prone to other forms of melanoma as Caucasians
• tends to invade dermis fairly quickly, so has a worse prognosis overall

• increased number of atypical melanoctyes along the dermoepidermal junction
• cells are not evenly dispersed, but crowd together, form variable sized nests, extend down follicles and sweat glands
• atypical melanocytes are pleomorphic (differ from one another), are larger than normal, and have nuclei of differing size, shape and staining intensity – cellular atypia
• atypical melanocytes may migrate upward within the epidermis – "buckshot spread"
• margins of lesion are not sharply defined, but seem to "peter out"
• the overall appearance is asymmetric – one half does not look like the other
• the pigmentation of atypical melanocytes is highly variable from one cell to another

• classic form = "Old World" Kaposi’s: elderly men of Mediterranean ancestry. Very slowly growing dark purple nodules on lower extremities
• epidemic form – AIDS patients/HIV: young men with widespread lesions, affecting any part of the cutaneous surface and mucous membranes
• endemic African form: similar to epidemic form, very aggressive
• association with Herpesvirus 8 (probably causative agent)

Seborrheic Keratoses

• often called "moles" or "warts" by patients – but aren’t
• average size is 1cm; can be up to 3cm
• flesh-colored, tan, brown, or black
• oval-shaped, elevated, "greasy" feel
• appear "stuck-on" the skin

Seborrheic Keratoses: histology

• hyperkeratosis (thickening of stratum corneum)
• acanthosis (thickening or non-keratinized layer)
• "straight line" can be drawn along bottom of tumor
• horn cysts are common
• no cellular atypia

• also called: acrochordons, soft fibromas, pedunculated fibromas
• neck and axillae of middle-aged, often obese adults
• flesh-colored, pinhead to grape-sized
• may become inflamed or necrotic (painful)
• histology: bag or sack-shaped specimen; some hyperkeratosis and acanthosis; collagen and sometime fat centrally

• very common
• can be found at any age
• legs most common site; also thighs, arms, trunk
• possibly a scar-like reaction to insect bite
• characteristic histology
• slow growing, round to oval, firm nodules
• deep component is attached to overlying skin
• a few millimeters to several centimeters
• pink to brown, darker in the center

• overlying epidermis is thickened (acanthosis) and hyperpigmented
• proliferation of bland-appearing spindle-shaped cells, randomly oriented, in upper and mid dermis
• variable number of small capillaries among the spindle cells

• first appear after 6-12 months, enlarge with body growth, regress in later life
• more numerous in light skinned persons
• maximal number in third decade; 24 (average) in women, 16 in men
• less than 5 remain after sixth decade

• junctional nevus – cells at dermoepidermal junction
• intradermal nevus – cells found only in dermis, not at junction
• compound nevus – combined features of junctional and intradermal nevi

• flat and uniform tan, brown, or dark brown
• less than 10mm – usually less than 6mm

• round, dome-shaped, evenly pigmented
• color lighter than junctional nevi
• often on face and neck
• often associated with coarse terminal hair
• may resemble basal cell carcinoma

• features of both junctional and intradermal nevi
• usually a histologic diagnosis

• change in size, shape, or pigmentation, especially is there is asymmetry
• located in area difficult to monitor: anogenital, scalp, soles
• persistent itching, or pain or bleeding
• have a low threshold for biopsying pigmented lesions

• children and young adults
• may be multiple
• hypopigmented oval halo around pre-existing nevus
• nevus eventually involutes and halo repigments (months to years)
• biopsy if central nevus appears atypical

• acquired, benign, firm, usually less than 10mm
• blue, blue-gray or blue-black
• most common on dorsa of hands or feet, but may occur anywhere
• small, stable, long-standing lesions do not require removal
• new onset or recent change: remove

• composed of benign melanocytes: little pleomorphism or cellular atypia
• overall distribution of melanocytes is symmetrical
• melanocytes tend to form nests (clustered groups) of cells
• cells become smaller with less cytoplasm as they descend deeper into the dermis
• in junctional nevi, the melanocytes or nests are all in contact with the dermoepidermal junction
• in intradermal nevi, all the cells have lost contact with the overlying epidermis; compound nevi have features of both junctional and intradermal nevi

• vascular malformation (not neoplasm) of dermal blood vessels
• always present at birth
• never spontaneously disappears
• macular in infancy; become papular and darker with age
• histology: increased number of blood vessels, with larger lumens, in upper dermis

• nuchal lesions (stork bite, salmon patch) occur in 1/3 of infants and do not fade; eyelids and glabella also
• Sturge-Weber syndrome: large facial lesions with cranial involvement and seizures
• Klippel-Trenaunay-Weber: limb lesions with soft tissue and bone hypertrophy

• "Strawberry mark"
• appears within the first months of life and grows rapidly
• reaches a certain size (1-8cm), then begins to regress
• usually complete involution by age 6
• face, trunk, legs, oral and vaginal mucosa
• histology: tightly packed, very small blood vessels; lumens not always present among the plump endothelial cells

• Senile angioma, lobular capillary hemangioma
• Almost universal with aging
• Trunk and proximal extremities
• Barely perceptible to 8mm, bright red to purple
• Histology: clusters (lobules) of tightly packed, small blood vessels in upper dermis

• usually persons younger than 30
• fingers, lips, mouth, trunk, toes
• positive "band-aid sign"
• moist, friable, bloody surface
• lesions do not spontaneously disappear
• histology: same as for cherry angioma, but often there is edema and epidermal erosion

• hypertrophic scars remain confined to site of original injury
• keloids extend beyond wound with clawlike extensions
• keloids may arise without history of injury, often in presternal site
• more common in blacks than whites
• earlobes, shoulders, upper back, chest
• hypertrophic scars tend to regress in time
• keloids may expand for decades
• histology: densely packed, bright pink collagen bundles in a haphazard array; increased number of fibroblasts and blood vessels in early lesions

• epidermoid cyst, wen, sebaceous cyst, infundibular cyst
• globular, dermal-to-subcutaneous nodule
• often an overlying pore or punctum
• face, neck, upper trunk, scrotum
• filled with "cheesy", rancid material (keratin)
• treatment of EIC: complete removal of cyst sac
• ruptured cysts can mimic a severe, localized infection – but are rarely infected
• histology: oval cyst has an epithelial wall resembling the surface epidermis, but the stratum corneum cells are "shed" into the center of the cyst

• 90% on scalp, more common in women
• often multiple lesions
• can be inherited trait
• no central punctum
• cyst often "pops out" on excision
• histology: similar to an epidermal inclusion cyst, but epithelial cells do not produce a stratum corneum, but rather a solid, pink, central ball of keratin

Digital Mucous Cyst

• myxoid cyst
• middle-aged to elderly
• dorsal aspect of distal phalanx of finger
• often just proximal to nail
• filled with clear, gelatinous substance
• histology: empty "spaces" in dermis, which were filled with mucin (hyaluronic acid) before processing

Neurofibroma

• soft, dome-shaped, skin colored, asymptomatic
• very common as a single or few scattered lesions
• multiple lesions may be associated with neurofibromatosis
• closely resembles intradermal nevus clinically
• histology: haphazard dermal collection of small, spindle-shaped cells with comma-shaped nuclei and wavy, pink cytoplasm

• older individuals
• lips, ears, face
• dark blue to purple, soft, fully compressible
• do not spontaneously resolve, but harmless
• histology: massively dilated vascular lumen in dermis