7 YEAR OLD WITH HISTIOCYTOSIS????

[TAR0519]

Hi everyone... My daughter is 7 years old, she has had Diabetes Insipidus since the age of  3 and is currently taking DDAVP. In March of this year her MRI of the brain, which showed SUBTLE thickening of pituitary stalk and an "ill defined area of T2 prolongation in the medial aspect of left frontal lobe". We have since had a repeat MRI 3 months after and this area did not "significantly change". We have another MRI scheduled for November.

After this test her endocronologist was concerned she possibly could have Histiocytosis.... She has undergone MANY bones scans, Xrays, Etc and thankfully they have all come back ok. This past month she has been having pain in her right heel/ankle area and so we went to a podiatrist who thought possibly could be a slight tendonits and had her wear an orthodic in her shoe. After 2 weeks pain seemed to get worse so we went back to her specialist at the Children's Hospital and they did an xray of her foot which shows..."moderate diffuse osteopenia without evidence of fractures, or malalignment. Questionable 0.5 x 0.3 cm lucent lesion involving the talus. Further evaluation with cross sectional imaging studies such as MRI or CT may be helpful for better delineation." She now has an appointment on Thursday for a PET scan.

I have 3 questions.... 1) Does anyone know what the abnormal spot on the brain MRI could be?  2) What is moderate diffuse osteopenia and why would a 7 year old have that? What is a lucent lesion and could this cause her pain? It seems like a very small size?

Thank you in advance if you can give an input. I would greatly appreciate it.
Teresa R