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

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?

Sag T1

Sag T2

Sag T1+C

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

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

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

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.

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

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

Answer Neoplasm Hemangioblastoma

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

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.

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

Answer Factor XIIIa Inhibin alpha CD31 Vimentin CD10 RCC

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

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

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

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

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

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

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

Answer Vimentin is strongly and diffusely positive in tumor cells.

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

Answer CD10 is negative in tumor cells.

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

Answer RCC is negative in tumor cells.

Question 13 What is your final diagnosis in this case?

Answer Hemangioblastoma

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

Answer WHO Grade 1