Dermatopathology Dr. Amitabha Basu
This is normal skin from a person with a dark complexion. The amount of skin pigmentation varies among races and individuals.
The Pilosebaceous unit. • Here are sebaceous glands, located next to a hair shaft ,forming the pilosebaceous unit.
Terms user in Dermatopathology MACROSCOPICTERMS MICROSCOPICTERMS
MACROSCOPIC TERMS Macule Papule Plaque Nodule Vesicle Bulla, blister Scale
Macroscopic Terms • Macule: A circumscribed change in skin color without elevation or depression.
Nodule: A palpable solid lesion of varying size, greater than 5 mm in diameter, which may be present in the epidermis, dermis or subcutis.
Vesicle: A circumscribed elevated lesion which contains free fluid. Vesicles are 5 mm or less in diameter.
Scale: Dry , horny plate like excrescence[ due to imperfect cornification].
MICROSCOPIC TERMS Hyperkeratosis Parakeratosis Acanthosis Dyskeratosis Papillomatosis Spongiosis
HyperkeratosisHyperplasia of the stratum Corneum. Qualitative abnormality of keratin.
Acantholysis LOSS OF INTERCELLULAR CONNECTION RESULTING IN LOSS OF COHESION.
Papillomatosis.Hyperplasia of the papillary dermis with elongation of the dermal papilla.
Topic • Benign Pigmented Lesion • Benign and Premalignant Epithelial Lesions • Malignant disease of skin • Acute inflammatory Dermatosis • Chronic inflammatory dermatosis • Bullous Disease
In albinism: this is melanocyte but no melanin formation Characterized by patchy loss of melanocytes. Autoimmune
Benign Pigmented Lesion Nevocellular Nevus • Melanocytic nevi (aka, "moles") are pigmented, benign neoplasms composed of modified melanocytes (nevus cells); they may be congenital or acquired lesions.
These are benign nevi. Small brown flat to slightly raised nevi. They are usually less than a centimeter in diameter. IT IS A CONGENITAL LESION
This is a larger flat 4 cm long pigmented nevus on the upper back. Such larger nevi are often congenital.
Nevocellular Nevus • Nests of small blue nevus cells.
Histologically : Compound and Junctional Nevus. • Compound Nevus • Definition: A type of mole formed by groups of nevus cells found in the epidermis and dermis . • Junctional Nevus. • Definition: A mole found in the junction (border) between the epidermis and dermis layers of the skin.
Congenital nevus • A nevus present at birth, may be pre-malignant depending on the size of the lesion .
Blue nevus • Raised, bluish lesion on his upper back.
Dysplastic Nevus Potential precursor to malignant melanoma often more than 5 mm across.
Dysplastic Nevus Tendency to occur in sun exposed as well as non-sun exposed body surfaces. Dysplastic nevi generally develop in early adolescence or adulthood, and are present in large numbers. Can occur in multiple members of the family and prone to develop melanoma. [ Heritable Melanoma Syndrome]
Benign and Premalignant Epithelial Lesions. • SEBORIC KERATOSIS • KERATOACANTHOMA • ACTINIC KERATOSIS
SEBORIC KERATOSIS: usually a benign and indolent neoplasm. If occur suddenly and Multiple in number you should suspect an internal malignancy [Paraneoplastic Syndrome]
SK's are common over the face, neck, and upper trunk. They are raised, rough-surfaced and brown coin-like plaques.
Broad bands of normal-appearing epidermal cells have large keratin-filled "horn cysts" within them.
KERATOACANTHOMA Flesh Coloured dome shaped nodule , with a central keratin filled plug. Site: check, ear, nose. Neoplasm that mimics Well Differentiated Squamous Cell Carcinoma
Keratoacanthoma: Neoplasm that mimics Well Differentiated Squamous Cell Carcinoma: heals spontaneously
ACTINIC KERATOSIS Less than 1 cm in diameter and sandpaper like consistency. It a dysplastic change and damage in the skin following Chronic Sun Exposure. Seen in Sun Exposed areas.
Actinic Keratosis A premalignant Condition.
Actinic Keratosis • Hyperkeratosis (increased amount of keratin) • Parakeratosis (presence of cell nuclei in the keratin layer, this is a sign of decreased turnover time of the epidermis) • Dysplasia (abnormal maturation of the epidermis; the cells have atypical morphology cytologically) • Solar elastosis (in which the dermis is stained blue rather than pink resembling the elastic tissue; this is a sign of sun damage)
Biopsy of the skin showing Solar Elastosis[ pale blue colored area, beneath the epidermis]
Lesions due to Sun exposure : Malignancy Malignant melanoma Squamous Cell Carcinoma Basal Cell carcinoma Major factor : Ultraviolet ray B