Cutaneous Neoplasms Flashcards
What are seborrheic keratoses?
- one of the most common cutaneous neoplasms
- develop in middle age or older patients
- brown/tan waxy papules and plaques with a “stuck on” warty appearance most commonly on face/trunk/upper extremities

What is the Leser-Trelat sign?
Sudden onset of multiple seborrheic keratoses associated with internal malignancy (most commonly stomach cancer)
What do seborrheic keratoses look like on histology?
- Hyperkeratotic, papillomatous and verrucous epidermis
- Horn and pseudo horn cysts (invaginations of keratin)
- Variable melanin pigmentation is present, accounting for the brown coloration seen clinically

What is actinic keratosis?
- also known as solar keratosis; common lesions that develop as a result of chronic sun damage
- middle aged to elderly onset (esp with fair complexion)
- red or tan/brown macues with “gritty” sandpaper like scales
- some lesions regress or may remain stable
- 0.1-10% become malignant squamous cell carcinoma
What does actinic keratosis look like on histology?
- Atypia of the basal layer of the epidermis
- Corneal layer is thickened with retained nuclei (parakeratosis)
- Loss of granular layer in some places
- Dermis contains thickened, blue-gray elastic fibers (solar elastosis), the result of chronic sun damage
Describe the etiology/prevalence of squamous cell carcinoma
- common neoplasm in older individuals (40+); 20% of all skin cancers
- UV radiation is the most common cause (DNA damage)
- Other predisposing factors include;
- chronic ulcers
- old burn scars
- HPV (esp in head and neck)
- toxic exposure (radiation, arsenic)
- immunosuppression (esp in solid organ transplant)
- 1-5% risk of metastasis in low risk area (~20% in high risk area such as lip/mucosa)
What are the clinical symptoms of squamous cell carcinoma?
- red scaly plaque
- risk of metastasis is related to the location and degree of invasion
- ~2-4% higher risk in immunosuppressed patients
How does SCC differ when it becomes invasive?
- invasive lesions (5% of SCCs) tend to be nodular and may ulcerate
- roughly 30% of invasive SCCs have metastatic potential
- classified as invasive when the neoplastic cells break through the basement membrane

What does SCC look like on histology?
- full-thickness dysplasia (characteristically involves the entire epidermis)
- disorganization of the epidermal architecture
- loss of maturation
- lack of polarity of cells

What is keratoacanthoma?
- variant of squamous cell carcinoma
- pink papule/nodule with a central keratin plug that grows rapidly (period of 2-10 weeks)
- can cause extensive local destruction
- occurs mainly on sun damaged skin
- some lesions will resolve spontaneously (or can become very aggressive)
- multiple lesions may be present in immunocompromised patients

What do keratoacanthomas look like on histology?
- exophytic lesions with an invaginating mass of keratinizing, well-differentiated squamous epithelium at the sides and bottom
- central keratin-filled crater that enlarges with the maturation and evolution of the lesion
- epidermis on either side of the lesion is thrown up into a well-formed collarette
- epithelium is typically characterized by well-differentiated, often pale-staining, eosinophilic, glassy cytoplasm showing a striking tendency towards keratinization

Describe basal cell carcinoma
- most common human cancer
- secondary to chronic sun exposure/UV radiation
- slow growing tumor that rarely metastasizes (unless immunocompromised)
- can be locally destructive
- associated with dysregulation of the sonic hedgehog or PTCH pathway (30-40%)

What does basal cell carcinoma look like on histology?
- several histologic variants
- multifocal growths originating from the epidermis (superficial type)
- nodular lesions growing downward into the dermis (nodular type) of variably basophilic cells with peripheral palisading.
- tumor cells are small and uniform with round, darkly staining nuclei and minimal cytoplasm
- characteristic clefting artifact between the tumor nodules and the stroma

What are melanocytic nevi?
- An above normal amount of melanocyte in the epidermis
- acquired from sun exposure
- congenital at birth (can be severe/widespread and increase risk of melanoma)

What are the histological classifications of nevi?
- junctional (epidermis only)
- compound (epidermis and dermis)
- intradermal (dermis only)

What are dysplastic nevi?
- clinically and histologically distinctive
- clincially larger than acquired nevi (>0.5 cm), irregular shape and uneven color
- may occur sporadically or in a familial form
- patients with multiple dysplastic nevi have increased risk of melanoma

What is dysplastic nevus syndrome?
- familial or sporadic
- familial variant is autosomal dominant (mutations in CDKN2A gene in 40% of cases)
- large number of dysplastic nevi (80+)
- increased incidence of melanoma
- patients can also develop other malignancies (e.g. pancreatic carcinoma)

Contrast familial and sporadic dysplastic nevus syndrome
- sporadic
- lower number of nevi (2-10)
- lifetime risk of melanoma ~10%
- familial
- hundreds of nevi
- lifetime risk of melanoma approaches 100%
**both show identical histological features (may be junctional of compound)

What is the prevalence of melanoma?
- represents 3% of all cutaneous malignancies
- 6th most common cancer in the US
- more common in white population… affects men and women equally
- most common on back in men
- most common on legs in women
- typically a disease of adulthood
What are the risk factors for melanoma?
- UV exposure at early age (most important risk factor)
- fair complexion and older age
- dysplastic nevus syndrome
- xeroderma pigmentosum (autosomal recessive disease)
- history of melanoma in the family
- tanning bed use
What are the clinical features of melanoma? (ABCDE)
- Asymmetry
- Borders (notched, uneven, or blurred)
- Color (uneven; shades of brown, tan, red, and black may be present… 3+ is concerning)
- Diameter (>6 mm)
- Evolving (change in color/size of the lesion)
What are the growth phases of melanoma?
- Radial growth phase
- melanocytes will proliferate within the epidermis (in situ… NO metastatic potential at this stage)
- Vertical growth phase
- dermal invasion and potential for metastasis
- extent of this phase determines the biological behavior (Breslow thickness/depth of invasion is the most important prognostic indicator)
- lesions >1.7 mm have greater potential for metastasis, <1 mm rarely metastasize
What factors determine a melanoma’s metastatic potential?
- Breslow thickness/depth of invasion is the most important prognostic indicator
- ulceration
- mitotic rate
- angioinvasion
**sentinel lymph node biopsy is considered if a lesion is deep
What are some types of melanoma?
- superficial spreading type (most common, 70%, located on back and extremities)
- nodular type (NO radial growth phase, poor prognosis)
- lentigo maligna type (most commonly located on the head and neck in sun exposed areas)
- acral lentignous type (located on the palm, sole, or beneath nail… most common in african americans)
What does a melanoma look like on histology?
- radial growth phase= asymmetric population of melanocytes within the epidermis (located along the dermal epidermal junction)
- melanoma cells are large with abundant cytoplasm, often showing dusty melanin pigmentation… often show pleomorphic vesicular nuclei with prominent eosinophilic nucleoli
- vertical growth phase= cells in dermis that grow in poorly formed nests or individual cells as an expansile nodules. There is lack of melanocytic maturation at the base of the lesion

What is mycosis fungoides?
- most common cutaneous lymphoma
- occurs in late adulthood with a male predominance
- usually presents as red or pink scaly patches
- stages of patch, plaque, and nodules
- usually chronic course although may become aggressive

What are the stages of mycosis fungoides?
- Patch stage: nonspecific dermatitis (patches often found on the lower trunk and buttocks… ill-defined patches of varying hue, often with a fine scale, irregular in size and shape) This stage may persist for many years before progression occurs
- Plaque stage: well-demarcated lesions which are often annular in shape, violaceous in appearance and occasionally scaly (may develop de novo or from patches)
- Tumor stage: usually develops in association with pre-existing lesions. The tumors are red in color, with a tense shiny surface. Ulceration may occur. The lesions usually measure 1 cm in diameter or more.
What is sezary syndrome?
- blood involvement of T cell lymphoma
- erythroderma (skin is diffusely red and scaly; sometimes misdiagnosed as chronic eczema)
- poor prognosis (survival 1-3 years)

What does mycosis fungoides look like on histology?
- mature T-cells show a tendency to colonize the epidermis (epidermotropism), although this is more evident in the patch and plaque forms than in tumor-stage disease.
- infiltrate contains large cells with highly irregular, convoluted or cerebriform nuclei, known as Sézary or mycosis cells.
- presence of atypical lymphoid cells in an intraepidermal vesicle (the Pautrier microabscess) is typical
