1. Case Study 43 Henry Armah, M.D., M.Phil.

2. Question 1 Clinical history: 50-year-old female with past medical history of gastroesophageal reflux disease, type 1 von Williebrand disease, ankylosing spondylitis, osteoarthritis, fibromyalgia and obstructive sleep apnea. He presented with upper back pains. Describe the abnormal spinal MRI findings?

3. Sag T2

4. Sag T1+C

5. Answer Homogenously contrast enhancing paravertebral mass anterior to the upper thoracic spine around the T1-T2 vertebral level.

6. Question 2 What are your differential diagnoses based on the patients’ age and the radiological findings?

7. Answer 1. Ganglioneuroma 2. Schwannoma 3. Neurofibroma 4. Paraganglioma

8. Question 3 The neurosurgeon performs a laminectomy with complete resection of the paravertebral mass, and requested an intraoperative consultation. Describe the gross findings of the mass?

9. Sag T2

11. Answer A single round-to-oval shaped encapsulated pink-red soft tissue mass.

12. Question 4 Describe the microscopic findings on this frozen section slide? Click here to view slide.here

13. Answer Spindle-cell neoplasm composed of cells with wavy nuclei arranged in loose fascicles in fibrocollagenous stroma and admixed ganglion cells.

14. Question 5 What is your intraoperative diagnosis? (A: Category such as Defer, Reactive/Non-neoplastic, or Neoplastic; B: More specific diagnosis or statement)

15. Answer A. Neoplasm B. Low-grade Spindle Cell Tumor, Favor Ganglioneuroma

16. Question 6 The permanent section has returned from histology. Describe the microscopic findings on this H&E slide? Click here to view slide.here

17. Answer Fragments of a neoplasm composed of Schwann cells and admixed ganglion cells. The neoplasm displays a low degree of cellularity and the majority on the neoplastic cells are spindled with wavy nuclei arranged in loose fascicles in a fibrocollagenous matrix. The ganglion cells are irregularly distributed in loose clusters and are irregular in size, frequently with multiple nuclei. No neuroblasts are seen. There is no evidence of anaplasia, mitotic figures, or necrosis.

18. Question 7 What additional immunohistochemical studies would you need to confirm the final diagnosis in this case?

19. Answer 1. EMA 2. Neurofilament 3. NeuN 4. S-100 5. Ki-67 (MIB-1)

20. Question 8 What do you see on this EMA immunostain slide? Click here to view slide.here

21. Answer EMA is negative in the tumor cells.

22. Question 9 What do you see on this Neurofilament immunostain slide? Click here to view slide.here

23. Answer Neurofilament is strongly and diffusely positive in the spindled tumor cells.

24. Question 10 What do you see on this NeuN immunostain slide? Click here to view slide.here

25. Answer NeuN is focally positive in few ganglion cells.

26. Question 11 What do you see on this S-100 immunostain slide? Click here to view slide.here

27. Answer S-100 is strongly and diffusely positive in the spindled tumor cells.

28. Question 12 What do you see on this Ki-67 (MIB-1) immunostain slide? Click here to view slide.here

29. Answer Ki-67 (MIB-1) is positive in the nuclei of less than 1% of the tumor cells.

30. Question 13 What is your final diagnosis in this case?

31. Answer Ganglioneuroma

32. Question 14 What is the corresponding WHO grade of this lesion?

33. Answer WHO Grade 1