This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
All of the following skin conditions are considered as skin markers for internal malignancy except 
Select and explain. 
A. Acanthosis nigricans, B. Dermatomyositis, C. Bullous pemphigoid, D. Pemphigus valgaris
D: Pemphigus valgaris
Answer: D: Pemphigus valgaris 
Explanation: Acanthosis nigricans, brown to grey - black velvety thickening of the skin in flexural areas, is caused by insulin resistance, obesity, drugs and underlying malignancy (esp. of the stomach and large intestine).Dermatomyositis results from an immune-mediated process triggered by various factors such as malignancy ( ovarian carcinoma, nasopharyngeal carcinoma, mycosis fungoides and lymphoproliferative malignancies ), drugs and infectious agents in genetically predisposed individuals. Bullous pemphigoid (BP) is an acquired, autoimmune, sub-epidermal blistering disease. It is also associated with underlying malignancies (SCC,RCC)Reference : page 303,274,283 IADVL's Concise Textbook of Dermatology