A 13 year old male presents with cold intolerance, lethargy and having to urinate 10 to 12 times per day (polyuria). On physical exam he is very short for his stated age (4’-11") and does not exhibit any pubic, axillary, or facial hair and has small genitals. He exhibits bilateral papilledema and bitemporal hemianopsia. There is normal tone and strength and muscle stretch reflexes are normal and symmetrical. Laboratory values reveals a mildly elevated hemoglobin (17 gm/dl) and hematocrit (51%), and normal platelet count and WBC count. Electrolytes are normal except for sodium which is elevated at 153 meq/L. Serum glucose was 104 mg/dl and a urinalysis revealed a specific gravity <1.004 with no protein or glucose present and normal cell count. Thyroid function studies revealed a decreased TSH, T₃ and T₄. MRIs of the head and neck were performed and represented in the following images.

1. The most likely diagnosis based on the above clinical presentation is:

A. Pituitary adenoma

B. Hypothalamic pilocytic astrocytoma

C. Craniopharyngioma

D. Pleomorphic xanthoastrocytoma

E. Colloid cyst

The patient was taken to surgery and the tumor was biopsied for frozen section and then partially resected. The following image represents the histopathology.

2. The diagnosis of this disease process is:

A. Pituitary adenoma

B. Colloid cyst

C. Hypothalamic pilocytic astrocytoma

D. Craniopharyngioma

E. Pleomorphic xanthoastrocytoma

3. These tumors arise from:

A. Fibrillary astrocytes

B. Remnants of Rathke’s pouch

C. Dysplastic choroid plexus

D. Neurons

E. Microglial cells

4. Tumors of this type arising in adults usually present clinically with:

A. Visual disturbances

B. Acromegaly

C. Hyperthyroidism

D. Chest lesions on x-ray

E. Focal motor seizures

5. Histologically, this tumor is:

A. A malignant epithelial tumor

B. Malignant glial tumor

C. An undifferentiated astrocytoma

D. Benign epithelial tumor

E. A benign glial tumor

6. The following statement(s) is/are true concerning craniopharyngioma:

A. The presence of calcifications on the scans is important in ruling out hypothalamic pilocytic astrocytoma in the differential diagnosis.

B. Patients with these tumors can present with diabetes insipidus, growth retardation, headaches and bitemporal hemianopsia.

C. Surgical partial resection is the usual treatment while needle aspiration with radiation is an alternative treatment.

D. All of the above

E. None of the above