Harp Pigmentation Disorders - MSK Exam 1

Freckles (ephelides)

Freckles (ephelides)

Freckles (ephelides)

Freckles (ephelides)

senile lentigo (lentigo senilis) / liver spots / age spots / solar lentigo / actinic lentigo

senile lentigo (lentigo senilis) / liver spots / age spots / solar lentigo / actinic lentigo

hockey sticks/dirty socks

senile lentigo (lentigo senilis) / liver spots / age spots / solar lentigo / actinic lentigo

Vitiligo (leukoderma)

Vitiligo (leukoderma)

Vitiligo (leukoderma)

Melanocytic nevi

Melanocytic nevi

Congenital nevus

Congenital nevus

extends into deep dermis

halo nevus

due to immune response to nevus cells

halo nevus

due to immune response to nevus cells

halo nevus

due to immune response to nevus cells

junctional melanocytic nevi

compound melanocytic nevi

junctional melanocytic nevi

nests present at dermal-epidermal junction

begin in early childhood

compound melanocytic nevi

nevus cells at junction and within dermis (appear to have fallen off/down into dermis)

intradermal melanocytic nevi

intradermal melanocytic nevi

intradermal melanocytic nevi

pigmentation lost at this point due to loss of junctional component —> nevus cells are only within dermis

MC nevi in adults - develop around puberty

poroma

cylindroma

cutaneous horn of actinic keratosis

Seborrheic keratosis

Seborrheic keratosis

white square = horn pseudocysts

Seborrheic keratosis

Seborrheic keratosis

Seborrheic keratosis

Seborrheic keratosis

Acanthosis nigricans

Acanthosis nigricans

Acanthosis nigricans

brown color at arrow shows increased melanin granules in epidermal basal layer

Fibroepithelial polyp

Fibroepithelial polyp

Fibroepithelial polyp

Fibroepithelial polyp

Epidermal Inclusion cyst

Epidermal Inclusion cyst

Epidermal Inclusion cyst

Epidermal Inclusion cyst

Epidermal Inclusion cyst

eccrine poroma

adnexal/appendage tumor with sweat gland differentiation

cylindroma

adnexal/appendage tumor of head/neck with apocrine sweat gland differentiation

histology: jigsaw puzzle-like

trichoepithelioma

adnexal/appendage tumor with hair

syringoma

adnexal/appendage tumor of eyelids and upper cheeks with eccrine duct differentiation

dense fibrous stroma

pilomatrixoma

adnexal/appendage tumor of hair matrix (in kids)

sebaceous adenoma

adnexal/appendage tumor of sebaceous gland

apocrine carcinoma

Benign fibrous histiocytoma (Dermatofibroma)

Benign fibrous histiocytoma (Dermatofibroma)

Composed of benign, spindle-shaped cells arranged in a well-defined, nonencapsulated mass within the mid-dermis

Overlying epidermal hyperplasia, characterized by downward elongation of hyperpigmented rete ridges

Benign fibrous histiocytoma (Dermatofibroma)

collagen balls (collagen trapping)

Benign fibrous histiocytoma (Dermatofibroma)

Composed of benign, spindle-shaped cells arranged in a well-defined, nonencapsulated mass within the mid-dermis

Overlying epidermal hyperplasia, characterized by downward elongation of hyperpigmented rete ridges

Benign fibrous histiocytoma (Dermatofibroma)

Composed of benign, spindle-shaped cells arranged in a well-defined, nonencapsulated mass within the mid-dermis

Overlying epidermal hyperplasia, characterized by downward elongation of hyperpigmented rete ridges

Benign fibrous histiocytoma (Dermatofibroma)

Composed of benign, spindle-shaped cells arranged in a well-defined, nonencapsulated mass within the mid-dermis

Overlying epidermal hyperplasia, characterized by downward elongation of hyperpigmented rete ridges

capillary hemangioma

capillary hemangioma

Delicate appearing vessels lined by flattened endothelial cells

vascular spaces are small or collapsed; intervening loose connective tissue stroma may contain larger arterioles or venules

cavernous hemangioma

contains large, dilated vascular spaces that may extend into underlying adipose tissue

Pyogenic granuloma

Inflammatory cell infiltrate often surrounds capillary-

like vessels

Pyogenic granuloma

Xanthoma and xanthelasma

Foamy macrophages have accumulated lipid material (phospholipid, triglyceride, cholesterol)

Xanthoma and xanthelasma

Stasis dermatitis

Stasis dermatitis

Hyperkeratotic and acanthotic epidermis at the right

Underneath shows bright red recent hemorrhage admixed with dark-brown hemosiderin granules and proliferating, thickened vascular channels