A 21-year-old man presents to a dermatologist for a concern about loss of skin pigmentation in a patchy distribution over the past 6 months. He denies itching or scaling of the lesions. He has type 1 diabetes mellitus which is controlled with insulin therapy. Vital signs are within normal limits. Physical examination reveals well-defined, depigmented macules on the skin that are coalescing into larger patches of pigment loss that are surrounded by normal skin. Under a Wood’s lamp, the depigmented areas emit a bright blue-white fluorescence.
Which of the following structures has the same embryonic origin as the cells involved in this patient’s disease process?
The correct answer is:
D) Sweat glands
The patient’s physical examination is consistent with vitiligo, which is an acquired disorder of pigmentation in which there is a loss of epidermal melanocytes. Melanocytes originates from neural crest cells which come from ectoderm. Of the answer choices, only the sweat gland are the only structures originating from the ectoderm.
Answer choice A: Adrenal cortex, is incorrect. The adrenal cortex originates from the mesoderm.
Answer choice B: Parathyroid glands, is incorrect. The parathyroid glands originate from the endoderm.
Answer choice C: Spleen, is incorrect. The spleen originates from the mesoderm.
Answer choice E: Thyroid gland, is incorrect. The thyroid gland originates from the endoderm.
Key Learning Point
Vitiligo is an acquired disorder of depigmentation due to a loss of epidermal melanocytes. The etiology of vitiligo is unknown though vitiligo is associated with autoimmune diseases such as type 1 diabetes and there seems to be a genetic basis for the disease. Melanocytes and sweat glands both originate from ectoderm.
