1. MedPix Medical Image Database COW - Case of the Week Case Contributor: MS-4 USU Teaching File Affiliation: Uniformed Services University

2. MedPix No: 5934 - History Pt Demographics: Age = 7 y.o. Gender = boy Patient is a 7 year-old male who presented with intractable vomiting of 24 hours duration. According to his mother, he was in his normal state of health until one day prior to coming to the hospital. On that day, he awoke in the morning and began to vomit. Mom kept him home from school and he continued to vomit throughout the day. He was seen in the ED at NNMC and bolused with 1L NS and started on maintenance IVF. Patient was also given 4mg Zofran, but was still unable to tolerate even small sips of clear fluids.The patient denies sore throat, abdominal pain, diarrhea, dysuria, rash, visual changes or neck pain. He has been afebrile. Several of his friends at school have experienced similar symptoms. Baseline labs were drawn and the patient admitted with a presumed diagnosis of viral gastroenteritis.On HD#1, patient began to complain of diffuse headaches and he continued to have emesis/dry heaves throughout the day. He was still unable to tolerate po liquids or Tylenol, and he was given a Tylenol suppository that evening for his headache with minimal relief. Patient remained afebrile.Emesis and unchanged headaches continued on HD#2. An acute abdominal series was WNL, but showed large amounts of stool. Because of this constellation of symptoms, a head CT and MRI were also obtained at this time. Downloaded by (-1)

3. MedPix No: 5934 - EXAM & LABS No abnormal finding on physical exam.Labs: CBC 7.4>15.3/44.3<420 Chem 7: 142/4.3 104/26 10/0.4 96

4. CT Scan 1) Large cystic and solid enhancing mass in the right cerebellum with associated hydrocephalus. - 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. Downloaded by (-1)

5. MRI 1) Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus. - 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. Downloaded by (-1)

6. MRI 1) Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus. - 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. Downloaded by (-1)

7. MRI 1) Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus. - 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. Downloaded by (-1)

8. MRI 1) Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus. - 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. Downloaded by (-1)

9. MRI Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus. Downloaded by (-1)

10. FINDINGS CT:1) Large cystic and solid enhancing mass in the right cerebellum with associated hydrocephalus. 2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine. MRI:1) Large cystic and solid enhancing mass in the right cerebellum. There is associated obstructive hydrocephalus.2) Linear enhancement pattern over the anterior surface of the pons in a pattern most likely representing venous engorgement rather than CSF spread of tumor. No evidence of drop mets in the spine.

11. DIFFERENTIAL DIAGNOSIS What is your Differential Diagnosis? 1) Juvenile pilocytic astrocytoma (JPA) - 2) Medulloblastoma - 3) Ependymoma

12. Diagnosis: (juvenile) pilocytic astrocytoma - surgically confirmed Dx Confirmed by:

13. DISCUSSION