Reason: is there any tumor near the right buttock or sacrum? Please define the margins of the plexiform neurofibroma of the left buttock. History: woman with NF1 complaining of pain in the buttock when she sits. She says it is in the right buttock but she has a left sided plexiform. Is there anything else? Note is made of a 5.1 x 1.4 x 4.1 cm focus of enhancing increased signal abnormality along the left gluteal crease with associated reticulation in the surrounding subcutaneous fat (image 31; series 14). This lesion appears to extend to and abut the 6 o'clock position of the anus and the possibility of perianal fistula formation cannot be completely excluded. No enhancing foci signal abnormality are identified within the right buttock to suggest a neurofibroma as clinically questioned. No additional enhancing mass lesions are identified. The imaged musculature of the pelvis is unremarkable. There is a small amount of fluid within the hips without evidence of a large effusion there is a small amount of peritrochanteric inflammation along the left greater trochanter which is likely of no clinical significance. Note is made of bilateral subcentimeter adnexal cysts/follicles.
5.1 cm focus of enhancing signal abnormality along the left gluteal crease, which is nonspecific, but consistent with the stated history of a neurofibroma. Alternatively, this could also represent perianal fistula formation or postsurgical granulation tissue in the correct clinical context. There is no evidence of neurofibroma formation within the right buttock, as clinically questioned.