<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: About Langerhans cell histiocytosis, true are all except:
Options:
A. Peak incidence less than 3 years of age
B. Radiosensitive
C. Diffuse form is known as Letterer-Siwe-disease
D. Gonadal involvement occurs
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is D: Gonadal involvement occurs. Explanation: d. Gonadal involvement occurs(Ref: Nelson's 20/e p 2484-2489; Ghai 8/e p 620-623)a. Peak incidence less than 3 years of age: True; More common and more severe in younger childrenb. Radiosensitive: True, as Bone lesions and Pituitary lesions, causing DI, respond well to radiotherapyc. Diffuse form is known as Letterer-Siwe disease: Trued. Gonadal involvement occurs: FALSE; Gonadal involvement is usually not seen in LCH.<|im_end|>
