Dermatopathology Flashcards
What is an Ephelis?
Freckle -increased melanin pigmentation along the stratum basalis without acathosis (hyperplasia of the keratinocytes) of the epidermis
What is Lentigo?
Ephelis with acanthosis
What are Blue Melanocytic nevi?
Spindle-shaped melanocytes usually with lots of melanin pigmentation in the dermis
What is a dysplastic nevus?
Nests of melanocytes at the dermoepidermal junction stretching from a rete ridge to adjoining rete ridge, surrounding lamellar fibrosis and perivascular chronic inflammation. (a rete ridge is an epidermal thickening that extends downward between dermal papillae)
What is Vitiligo?
Localized loss of skin pigmentation due to autoimmune destruction of melanocytes.
What is a Halo Melanocytic Nevus?
A nevus with hypopigmentation around it indicating that the patient’s immune system is attacking the hyperproliferative melanocytes.
Name the 2 tumors markers often found in melanomas
S100 antigen HMB-45 antigen
What is Pagetoid Growth?
Histological feature of melanoma -it means melanocyte hyperplasia in layers of the epidermis more superficial than just the stratum basalis
What is Breslow’s Level?
Greatest neoplastic depth of invasion of melanoma. -measured in millimeters -measurement is from the stratum granulosum of the epidermis to the depth of the tumor -the greater the depth the more likely for metastasis to occur
What is Clark’s Level?
Grading of melanomas: levels 1-5 I: melanoma in situ II: melanoma invading papillary dermis but NOT filling it III: melanoma invading and filling papillary dermis IV: melanoma invading reticular dermis V: melanoma invading SubQ fat of hypodermis
Name the 4 major types of melanoma
- Superficial Spreading: growth along stratum basalis, low chance of invasion thru basement membrane 2. Nodular: invades thru basement membrane early 3. Acral-Lentiginous: radial growth on acral skin (hands and feet) 4. Neurotropic: blue melanocytic nevi (in dermis) become malignant
What is Seborrheic Keratosis?
Bening, flat, coin-like plaques. They arise from proliferation of benign basaloid keratinocytes leading to hyperkeratinization and horn pseudocyst formation
What is the Leser Trelat Sign?
Explosive Onset of seborrheic keratosis that are often a sign of internal malignancy as part of a paraneoplastic syndrome.
What is Acanthosis Nigricans?
Benign acanthosis of the epidermis with hyperpigmentation along the basal layer. Often seen in obese patients, diabetics, other endocrine disorders. The skin has localized areas of thickened, dark leathery appearance usually on flexor surfaces.
What is a Firbroepithelial Polyp?
Skin tag -fibrovascular core surrounded by benign squamous epithelium of the epidermis
What is a keratoacanthoma?
A proliferation of squamous cells in the epidermis usually on sun-exposed skin. Histologically it looks like squamous cells surrounding a central nodule of keratin.
What is actinic keratosis?
Series of dysplastic changes in the epidermis on sun-exposed skin. Precursor for squamous cell carcinoma of the skin. Histology shows cytological atypia including parakeratosis (retention of nuclei even in the stratum corneum)
What is Bowen Disease?
Squamous Cell Carcinoma in situ of the skin, histology shows atypical keratinocytes in all layers of the epidermis.
What are “rodent ulcers”?
Advanced basal cell carcinoma lesions that invade underlying bone or facial sinuses.
Most aggressive type of basal cell carcinoma.
Morphea (Sclerosing) Subtype
Why is xeroderma pigmentosum a risk factor for all the epidermal cell cancers?
The disease results in a failure of Nucleotide Excision Repair (NER). NER is required to repair pyrimidine dimers that are formed on DNA from UV exposure. If the dimers occur in a region that regulates the cell cycle it can lead to cancer.
What is a benign Fibrous Histiocytoma?
Benign proliferation of fibroblasts in the dermis. Most common form is a Dermatofibroma that occurs in the legs of middle-aged women. Histology shows foamy macrophages and/or giant epithelioid histiocytes
What is Dermatofibrosarcoma Protuberans?
Primary fibrosarcoma in the dermis that is aggressive but rarely metastasizes. Microscopy shows atypical fibroblasts in a “storiform” (basket weave) pattern.
Describe Xanthomas and name the two general types.
A collection of foamy histiocytes in the dermis forming a tumor. 1. Eruptive Xanthoma: associated with lipid and TG levels in the blood, yellow papules on the skin 2. Tuberous or Tendinous Xanthomas: yellow nodules that form on Achilles tendon or extensor tendons
