1. CASE OF THE WEEK 61 29 year old female patient was referred to the practice of Martin Wangler, DC, MME by her family doctor with lumbo-sacral pain. Her pain was load- dependant; no radiation into the legs; L5/S1 dysfunction.

2. What are the abnormal findings? What additional view or views would be helpful? What is the differential diagnosis? What follow-up questions are indicated? L

3. Answers What are the abnormal findings? There is a fairly well marginated, expansile, lytic lesion with central opacification and with a lobular structure medial to the right acetabulum (within the body of the pubic bone). What additional view or views would be helpful? Spot views of the hip may be helpful MRI indicated DDX? Enchondroma Chondromyxoidfibroma Chondroblastoma What follow-up questions are indicated? Does her right groin hurt ? Does she have pain at night? R R

4. Same patient, spot view of her right S. pubis R

5. Follow-up: MRI was the imaging modality of choice for the diagnosis of this lesion. The lesion is in the Os pubis lat region. MRI was the imaging modality of choice for the diagnosis of this lesion. The lesion is in the Os pubis lat region.

6. Examples of MRI follow-ups 2.5 x 2.4 x 3 cm intraosseous lesion within os pubis lat on the right side: Chondromyxoidfibroma or Chondroblastoma. The lesion looks benign, although obviously expansile. No cortical destruction, no soft tissue mass, no periosteal reactions.

7. Examples of MRI follow-ups Another lesion was found: DH L5/S1 with no nerve root or thecal sac compression noted on these slices

8. MRI findings Small DH L5/S1 without neurological compression. Small DH L5/S1 without neurological compression. Chondromyxoidfibroma or Chondroblastom: The patient is presently at the Insel Spital in Berne for definite diagnosis (Nuklearmedizin) Chondromyxoidfibroma or Chondroblastom: The patient is presently at the Insel Spital in Berne for definite diagnosis (Nuklearmedizin)

9. Additional Comments If this turns out to be a Chondroblastoma, Martin should publish the case as these are painful lesions that most often are located in epiphyses or apophyses (especially the greater trochanter) and thus this picture does not fit this patient. Chondromyxoid fibroma is more likely due to symptoms and location although it is very rare. It would not be surprising if this still turns out to be an enchondroma. The symptoms and plain film findings fit that diagnosis well.