This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Sebaceous cyst does not occur in the ................................... \nSelect and explain. \nA. Scalp, B. Scrotum, C. Back, D. Sole', 'role': 'user'}, {'content': 'Answer: D \nExplanation: • Epidermoid cyst results from proliferation of epidermal cells within a circumscribed space of dermis (which had got implanted within the dermis)\n• Sebaceous cyst is a misnomer as the cysts are not of sebaceous origin and the white creamy material filled within is not sebum, but is keratin (desquamated epithelial cells)\n• Type of retention cyst (secretions are pent up in a gland owing to blockage of the duct)\nPathology\n• Cyst wall consist of a layer of epidermis oriented with the basal layer superficial and more matured layers are deep.\n• Desquamated cells (keratin) collect in the centre and form creamy substance of the cyst.\nClinical Features\n• Usually asymptomatic, unless get infected or inflamed and become painful\n• Firm, round, flesh colored to yellow or white subcutaneous nodules of variable size.\n• Central punctum\xa0may teether the cyst to the overlying epidermis, from which the white creamy material can be expressed.\n• Rarely malignancies\xa0(BCC, SCC) can develop in epidermoid cyst.\n• No punctum in scrotal and scalp sebaceous cyst.\nTreatment\n• Excision with the wall is treatment of choice.\n• Infected cyst: Incision and drainage (After resolution of the abscess, cyst wall must be excised to prevent recurrence)', 'role': 'assistant'}]