This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skin tumors, Subject name: Dental
[{'content': 'True about acanthosis nigricans \nSelect and explain. \nA. Seen in axilla, B. It is associated with insulin resistance, C. It signifies internal malignancy, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: ACANTHOSIS NIGRICANS Classification * Hereditary AN \x02* HAIR-AN syndrome: \x02 Several endocrine disorders associated. HyperAndrogenism, Insulin Resistance and Acanthosis Nigricans. * Benign acquired AN: \x02 Obesity associated. Earlier called pseudo AN. * Drug-induced AN: \x02 Nicotinic acid, stilbestrol, coicosteroids, oral contraceptives. * Malignant AN: \x02 Adenocarcinoma of stomach and genitourinary tract. Clinical Features Morphology:- Begins as hyperpigmentation and area appears \x02 diy. Gradually, skin thickens and becomes velvety. \x02 Surface of skin appears rugose and mammillated. The edge of lesion feathered. Sites of predilection:- Neck, axillae, and groins frequently. Other flexures (antecubital and popliteal fossae, face sometimes; submammary folds, wrists less frequently. Associations:- Depends on type of AN: * HAIR-\x02 AN syndrome: Several endocrine disorders associated. Insulin-resistant diabetes mellitus, hyperandrogenic states, Cushing's syndrome * Benign acquired AN\x02: Skin tags in the major flexures. * Malignant AN: \x02 Several associations: Tripe palms,\x05 Mucosal involvement, Severe itching.\x05 Investigations Rule out:- Underlying endocrinopathies.\x02 Underlying malignancies.\x02 Treatment:- Retinoic acid (0.025%) topically, response often \x02 unsatisfactory. Ref:- Neena khanna; pg num:- 37,38", 'role': 'assistant'}]