Dermopath 2 Flashcards
(25 cards)
What are the major subtypes of melanoma?
Superficial spreading melanoma, nodular melanoma, lentigo maligna melanoma, and acral lentiginous melanoma.
What is the ABCDE rule for melanoma diagnosis?
Asymmetry, Border irregularity, Color variation, Diameter >6 mm, Evolving size, shape, or color.
Which genetic mutation is most commonly associated with melanoma?
BRAF mutation, specifically V600E.
What histological feature distinguishes lentigo maligna melanoma?
Proliferation of atypical melanocytes along the dermoepidermal junction in a lentiginous pattern.
How does acral lentiginous melanoma typically present?
Dark pigmented macules or nodules on palms, soles, or under the nails, more common in darker-skinned individuals.
What is the significance of Breslow thickness in melanoma?
Breslow thickness measures the depth of invasion in millimeters and is a key prognostic factor in melanoma staging.
What is the histological hallmark of nodular melanoma?
Vertical growth phase with prominent dermal invasion and lack of radial growth phase.
What immunohistochemical markers are used to confirm melanoma?
S-100, HMB-45, and Melan-A (MART-1).
What is the clinical presentation of basal cell carcinoma (BCC)?
Pearly papules with telangiectasia, central ulceration, or pigmented nodules.
What histological feature is characteristic of BCC?
Nests of basaloid cells with peripheral palisading and stromal retraction.
What is the most common precursor lesion for squamous cell carcinoma (SCC)?
Actinic keratosis, presenting as scaly, erythematous plaques in sun-exposed areas.
How does SCC in situ (Bowen’s disease) appear histologically?
Full-thickness epidermal atypia with no invasion of the dermis.
What is the primary histological finding in dermatofibroma?
Spindle cells in a storiform pattern with overlying epidermal hyperplasia.
What is the classic histological feature of Kaposi sarcoma?
Spindle cell proliferation with slit-like vascular spaces and extravasated erythrocytes.
How is mycosis fungoides identified histologically?
Atypical T-cells forming Pautrier microabscesses in the epidermis.
What is the clinical presentation of Merkel cell carcinoma?
Rapidly growing, painless, red to purple nodule often found on sun-exposed areas in elderly patients.
What immunohistochemical markers are used for Merkel cell carcinoma?
Cytokeratin 20 (CK20) and Merkel cell polyomavirus (MCPyV).
What is the histological hallmark of seborrheic keratosis?
Exophytic proliferation of basaloid cells with keratin-filled cysts (horn cysts).
What distinguishes a dermatofibrosarcoma protuberans (DFSP) histologically?
Spindle cells arranged in a storiform pattern with CD34 positivity.
What is the characteristic finding in cutaneous leiomyoma?
Bundles of smooth muscle cells with elongated nuclei arranged in intersecting fascicles.
What are the clinical subtypes of Kaposi sarcoma?
Classic, endemic, iatrogenic (immunosuppression-related), and AIDS-associated Kaposi sarcoma.
How does desmoplastic melanoma differ histologically from other melanoma subtypes?
Desmoplastic melanoma shows spindle cells in a collagenous stroma, often lacking the typical melanocytic markers.
What histological feature is indicative of acanthosis nigricans?
Hyperkeratosis, papillomatosis, and hyperpigmentation of the epidermis.
How does actinic keratosis present histologically?
Dysplastic keratinocytes in the basal layer with overlying parakeratosis and solar elastosis.
