1. Case Study 39
Henry Armah, M.D., M.Phil.

2. Question 1
Clinical history: 59-year-old male with past medical history of von Hippel Lindau syndrome, bilateral renal cell carcinomas, bilateral nephrectomies, and right kidney transplant 10 years prior. He presented with a 3-week history of lower extremity numbness, instability and difficulty walking, left leg worse than right. Describe the abnormal spinal MRI findings?

3. Sag T1

4. Sag T2

5. Sag T1+C

6. Answer
Intradural extramedullary oval homogenously contrast enhancing mass at the T7 vertebral body level compressing and displaying the spinal cord within the thecal space.

7. Question 2
What are your differential diagnoses based on the patients’ age, past medical history, and the radiological findings?

8. Answer Hemangioblastoma Metastatic renal cell carcinoma Meningioma
Schwannoma
Hemangiopericytoma
Solitary fibrous tumor
Paraganglioma

9. Question 3
The neurosurgeon performs a laminectomy with resection of the mass, and requested an intraoperative consultation. Describe the microscopic findings on this frozen section slide? Click here to view slide.

10. Answer
Neoplasm composed of numerous thin-walled vessels and intervening vacuolated stromal cells.

11. Question 4
What is your intraoperative diagnosis? (A: Category such as Defer, Reactive/Non-neoplastic, or Neoplastic; B: More specific diagnosis or statement)

12. Answer
Neoplasm
Hemangioblastoma

13. Question 5
The permanent section has returned from histology. Describe the microscopic findings on this H&E slide? Click here to view slide.

14. Answer
Fragments of a neoplasm composed of numerous thin- walled vessels lined with abundant vascular cells, and interspersed vacuolated stromal cells. Occasional stromal cells with large atypical and hyperchromatic nuclei are identified. There is no evidence of anaplasia, mitotic figures, or necrosis. There are focal areas of hemorrhage and hemosiderin deposition.

15. Question 6
What additional immunohistochemical studies would you need to rule out other important differential diagnoses and confirm the final diagnosis in this case?

16. Answer
Factor XIIIa
Inhibin alpha
CD31
Vimentin
CD10
RCC

17. Question 7
What do you see on this Factor XIIIa immunostain slide? Click here to view slide.

18. Answer
Factor XIIIa is patchy positive in the neoplastic stromal cells.

19. Question 8
What do you see on this Inhibin alpha immunostain slide? Click here to view slide.

20. Answer
Inhibin alpha is strongly and diffusely positive in the neoplastic stromal cells.

21. Question 9
What do you see on this CD31 immunostain slide? Click here to view slide.

22. Answer
CD31 is negative in the neoplastic stromal cells, but highlights the rich vasculature of the tumor.

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

24. Answer
Vimentin is strongly and diffusely positive in tumor cells.

25. Question 11
What do you see on this CD10 immunostain slide? Click here to view slide.

26. Answer
CD10 is negative in tumor cells.

27. Question 12
What do you see on this RCC immunostain slide? Click here to view slide.

28. Answer
RCC is negative in tumor cells.

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

30. Answer
Hemangioblastoma

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

32. Answer
WHO Grade 1