Dermatopathology of Skin Lesions MCQs

Explanation: Langerhans cells do originate from bone marrow, but they are primarily located in the stratum spinosum, not the granular layer. Key epidermal cell types and their locations: Langerhans cells: Antigen-presenting dendritic cells derived from bone marrow; mostly in stratum spinosum. Melanocytes: Neural crest-derived pigment cells; found in stratum basale. Merkel cells: Mechanoreceptors involved in touch sensation; located in stratum basale. Keratinocytes: Main epidermal cells with abundant keratin intermediate filaments, forming stratified squamous keratinized epithelium.

Multiple lesions on limb and trunk with B/L symmetric Nerve thickening are pointing towards lepromatous end of spectrum, which could be BL or LL. BL - hypoesthetic lesions LL - normoesthetic lesions and glove and stocking type anesthesia. Reference: Rooks textbook of Dermatology, 9 th edition, Chapter 28, page 10

Combination of giant hemangioma, thrombocytopenia, and consumption coagulopathy KMS is an infrequent but potentially fatal complication of rapidly growing vascular lesions in infants The low platelet count in Kasabach-Merritt syndrome is due to a combination of increased destruction and sequestration of platelets within the expanding vascular tumour. The tumor here is infantile haemangioma. MC vascular tumor in infants Reference: Rook's dermatology, 9 th Edition, Chapter 101, Page 4

Combination of psoralens and ultraviolet light (UVA, 320- 400 nm) - PUVA Psoralen intercalates into the DNA double helix where it is ideally positioned to form adduct(s) with adjacent pyrimidine bases, preferentially thymine, upon excitation by an ultraviolet photon Reference: Rooks textbook of dermatology, 9 th edition, chapter 35, page 26

Darier disease, previously known as keratosis follicularis, is a rare autosomal dominant genodermatosis characterized by keratotic papules and longitudinal eyrthronychia; it is caused by mutations in the ATP2A2 gene, encoding a calcium pump within the endoplasmic reticulum. Reference: Rooks textbook of Dermatology, 9 th Edition, Chapter 66, Page 2

Desmosomes are the intra-epidermal inter-cellular adhesions that are helpful in connecting keratinocytes in the epidermis. Max concentration is in spinous cells. Desmosomes contain various proteins : Desmogleins, desmocollin and desmoplakin. Damage to the desmosomes leads to separation of keratinocytes leading to acantholysis. The cells separate from each other, become round with large nucleus and perinuclear halo called as acantholytic cells. Reference: Rooks textbook of dermatology 9th edition, chapter 2, page 18

An increase in number of cells in the stratum spinosum / Prickle cell layer of the epidermis Reference: Rooks textbook of dermatology, chapter 37, page 14

Miliaria, or eccrine miliaria, - Blocked eccrine sweat glands and ducts. The obstruction leads to leakage of sweat into the epidermis or dermis, resulting in cellular overhydration, swelling, and further occlusion of the ducts. It is most common in warm, humid climates during the summer months. The 3 main types of miliaria are crystallina, rubra, and profunda. Reference: Rook’s Textbook of Dermatology, 9th Edition, Chapter 94, Page 12