Histopathology 13: Skin Pathology Flashcards
Baby with itchy yellow scales on his scalp and nappy rash.
Most likely diagnosis ?
Seborrheic dermatitis (cradle cap)
Rain drop plaques seen in children 2 weeks post strep throat infection.
Most likely diagnosis ?
Guttate psoriasis
What type of hypersensitivity reaction is psoriasis ?
Type IV T cell mediated
Koebner phenomenon
Auspitz’s sign
Histology: Parakeratosis, loss of rete ridges and “test tubes in a rack appearance”
Most likely diagnosis ?
Psoriasis
Purple, pruritic, polygonal, papules and plaques with Wickam’s striae
Histology: Hyperkeratosis with sawtoothing of rete ridges
Most likely diagnosis ?
Lichen Planus
Histology: Linear deposition of IgG antibodies bound to hemidesmosomes of the basement membrane
Nikolsky’s sign -ve
Bullous pemphigoid
Histology: Net like pattern of IgG deposits on desmosomal proteins causing intraepidermal bullae
Nikolsky’s sign +ve
Pemphigus
Which premalignant skin lesion is hard to differentiate from SCC and is described as: a dome shaped nodule with a necrotic, crusted centre which spontaneously clears in 2-3 weeks ?
Keratocanthoma
What is the difference between Bowen’s disease and SCC ?
Bowen’s disease is premalignant and does not invade through the basement membrane
Lesion with pearly rolled edges and telangiectase with palisading nuclei on histology.
Most likely diagnosis ?
BCC
List 4 subtypes of malignant melanoma ?
Superficial spreading melanoma
lentigo maligna melanoma
nodular malignant melanoma
Acral lentigous melanoma
Where do you see acral lentigous melanoma ?
Palms and soles
Salmon pink rash, herald patch, christmas tree distribution.
Most likely diagnosis ?
Pityriasis rosea
