Transcript Case Study 11 - University of Pittsburgh

Case Study 11
Gabrielle Yeaney, M.D.
Question 1
The patient is a 23-year-old male with headaches,
dizziness, anusea, vomiting, diabetes insipidus, and no
seizure history. Hormone studies revealed adrenal
insufficiency, hypothyroidism and low IGF-1.
Describe the MRI findings (location, enhancement,
etc.).
MRI Sagittal T1
MRI Sagittal T1 post-contrast
MRI axial T1 post-contrast
MRI Coronal T1 post-contrast
Answer
There is a cystic pineal mass (6 mm) with an enhancing
solid component. The pituitary stalk (infundibulum) is
enlarged.
Question 2
Give a differential diagnosis based on clinical history and
MRI findings.
Answer




Germ cell tumor
Pineo-cytoma or -blastoma
Lymphoma
Metastasis
Rare Stuff
 Langerhans cell histocytosis
 Neurosarcoidosis
 Tuberculosis
 Infiltrative glioma
Note: Pituitary adenoma and other lesions of the suprasellar variety
(craniopharygioma, etc) are not likely in this scenario because of
the synchronous involvement of both the stalk and the pineal
gland.
Question 3
Using endoscopic endonasal approach, the contents of
the pituitary stalk are identified. The surgeon notes a
distinct mass within the stalk and gives you a small
biopsy. Describe the cytologic features of the touch
preparation.
Click here to view slide.
Answer
The touch prep shows a polymorphic population of
cells. There are abundant small lymphocytes and a few
plasma cells. A second cell type consists of large cells
each with a single round hyperchromatic nucleus with one
or more macronucleoli. Mitotic figures are present. The
cells on the touch prep are dyshesive.
Question 4
What is your intraoperative diagnosis? (A.
Neoplastic/Defer/Non-neoplastic, B. ______)
Answer
A. Neoplastic
B. Poorly-differentiated neoplasm, lymphoid-rich; C.
Germinoma versus lymphoma--r some variation of
the above.
Question 5
What additional lab values might be ascertained from the
surgeon to help with your diagnosis?
Answer
Blood or CSF levels of alpha-fetoprotein (AFP), betahuman chorionic gonadotrophin or carcinoembryonic
antigen if they were drawn. High levels of AFP imply the
presence of yolk-sac tumor, and high levels of beta-HCG
suggest choriocarcinoma.
Question 6
Review the permanent section. Describe the histologic
features.
Click here to view slide.
Answer
 Sheets of large cells showing syncytial growth
 Diffuse infiltrate of chronic inflammatory cells (esp.
lymphocytes) admixed with tumor cells
 Tumor cells are large with vacuolated cytoplasm,
vesicular nuclei and prominent nucleoli
 Crush artifact
 Apoptotic and mitotic figures
Question 7
What is your final diagnosis?
Answer
Germinoma
Question 8
Tumor cell membranes show reactivity for c-kit (CD117)
seen here. What other immunohistochemical studies
might confirm your diagnosis?
Click here to view slide.
Answer
Placental alkaline phosphatase (PLAP) is usually positive
in germinoma but tends to be less "crisp" than ckit. OCT4 is sensitive for seminoma, germinoma and
embyronal carcinoma. Syncytiotrophoblasts are reactive
for beta-HCG and cytokeratins. Syncytiotrophoblasts may
be seen in germinoma in small numbers and are not
necessarily indicative of choriocarcinoma.
Question 9
What classic histologic feature would lead you to a
diagnosis of yolk-sac tumor (either pure or as a
component of a mixed germ cell tumor)? What
immunohistochemical stain is usually expressed in yolksac tumors?
Answer
Schiller-Duval body--"endodermal sinus" that looks like a
glomeruloid structure; AFP
Question 10
What immunohistochemical stain is reactive for
embryonal carcinoma?
Answer
CD30
Question 11
What other imaging studies should be obtained in this
patient (now or follow-up)?
Answer
MRI of spine (to look for drop mets) and MRI/CT of
chest/abdomen/pelvis--Metastasis outside of the CNS is
rare but can occur. Abdominal cavity involvement can
occur after ventriculoperitoneal shunt placement. There
have been reports of CNS germ cell tumors associated
with second lesions in the gonads.
Question 12
What is the prognosis and standard treatment for this
neoplasm?
Answer
Germinomas are often curable as they are extremely
radio- and chemo-sensitive. 5-year-survival rates are 8096%.