<prompt> True about histiocytosis X include the following EXCEPTSeborrheic dermatitis is a known featureBirbecks granules are characteristic featureLytic bony lesions are knownAssociated with angiomyolipoma of kidney  <response>: Ans. d Associated with angiolipoma of kidney. Ref. Nelson Textbook of Pediatrics 171728; TABLE 499-1Eosinophilic Granuloma EG EG usually occurs during the first 3 decades and is most common in boys 5-10 yr. The skull is most commonly affected, but any bone may be involved. Usually present with local pain and swelling. There is often tenderness and warmth in the area of bone. Spinal lesions may cause pain, stiffness, and occasional neurologic symptoms. X-ray: Lytic lesions have well-defined or irregular margins geographic skull with expansion of the bone. Spine involvement may cause uniform compression or flattening of the vertebral body vertebra plana. No extraskeletal visceral involvement distinguishes EG from the other forms of Langerhans cell histiocytosis Hand- Schiiller-Christian or Letterer-Siwe variants, which have a less favorable prognosis. Treatment includes curettage and bone grafting, low-dose radiation therapy, or steroid injection. Observation for symptomatic lesions is fine because most lesions heal spontaneously and do not recur. 