A 46-year-old man comes to the office with the skin lesions shown in the photograph below. The patient first noticed the lesions a week ago after he returned from a trip to Hawaii. He has not had any other significant rashes or skin lesions but does have a history of autoimmune thyroiditis. Which of the following would most likely be seen on histopathologic examination of this patient's lesions?

Question

A 46-year-old man comes to the office with the skin lesions shown in the photograph below.  The patient first noticed the lesions a week ago after he returned from a trip to Hawaii.  He has not had any other significant rashes or skin lesions but does have a history of autoimmune thyroiditis.  Which of the following would most likely be seen on histopathologic examination of this patient's lesions?

Quizplus · Accepted Answer

11ec160b_3906_c946_9249_11e84b6a300e_MD0001_00 This patient has vitiligo, which is characterized by flat, well-circumscribed patches of depigmentation of variable size due to the partial or complete loss of melanocytes. These lesions often manifest by the second or third decade of life and can be more obvious in individuals with darkly pigmented skin. Vitiligo classically erupts on the face, extremities, axillae, groin, and over hard bony surfaces (eg, knees). Histologic examination of the affected epidermis would demonstrate the absence of melanocytes and melanin pigment. The pathogenesis of melanocyte loss in vitiligo is likely a combination of autoimmune activity, neurohumoral toxicity specific for melanocytes, and melanocytic self-destruction (eg, toxic intermediate exposure during melanin synthesis). Autoimmune activity seems to have the strongest correlation with vitiligo due to the presence of circulating melanocyte antibodies in patients and the high prevalence of concurrent autoimmune disorders (e.g., type I diabetes mellitus, pernicious anemia, Addison disease, autoimmune thyroiditis). (Choice B) Lentigines are small, benign pigmented lesions characterized by linear melanocytic hyperplasia. (Choice C) Café-au-lait spots demonstrate increased melanosome aggregates within the melanocyte cytoplasm. These macules are hyperpigmented and associated with neurofibromatosis type 1. (Choice D) Postinflammatory hypopigmentation can occur after significant inflammatory skin lesions (eg, discoid lupus, psoriasis) and is characterized by redistribution of existing melanin within the skin and/or reduced transfer of melanin to keratinocytes. (Choice E) Individuals with albinism have melanocytes that do not produce melanin because of absent or defective tyrosinase. Educational objective: Vitiligo is a common condition characterized by the loss of epidermal melanocytes. It occurs more commonly in patients with autoimmune disorders (eg, autoimmune thyroiditis, type I diabetes) and results in well-defined, variably sized patches of hypopigmentation.

A 46-Year-Old Man Comes to the Office with the Skin