Pituitary tumors & Hemangioblastoma

Sellar anatomy

Diseases related to hypothalamic-pituitary axis

• Neoplastic disorders

    Pituitary adenoma, craniopharyngioma, germinoma and teratoid tumor, hypothalamic and optic glioma,   
    meningioma

• Non-neoplastic cystic lesions

    Rathke’s cleft cyst, mucocele, arachnoid cyst, epidermoid cyst

• Inflammatory disorders

    Pituitary abscess, lymphocytic hypophysitis

• Head trauma

    Basal skull fracture, severe cerebral contusion

 

 

Pituitary adenoma

• Benign tumor arising pituitary gland

    4-5th decades, female>male

• Classification according to hormonal secretion

    Non-functioning (hormone non-secreting): 15~30%

    Functioning (hormone secreting): 48% prolactin, 10% GH, 6% ACTH, 1% TSH

• Classification according to tumor size

1. Micro-adenoma ( < 1 cm)
2. Macro-adenoma ( >1 cm)
3. Giant adenoma  ( > 4 cm)

 

Non-functioning pituitary adenoma

• Sx & Sn by mass effect

    Visual manifestations: impairment of visual acuity, visual field defect

     bitemporal hemianopsia due to optic chiasm compression

    Cranial nerve palsies : EOM (extra-ocular muscle) limitations, facial numbness & pain

    Headache

    Obstructive hydrocephalus: foramen of Monro, 3rd ventricle

    Pseudo-hyperprolactinemia (<150 ng/mL) due to stalk compression effect

    Hypopituitarism: later stage (Go Look For The Adenoma, Please!)

    Diabetes insipidus

Table 44.3 Significance of prolactin levelsa
PRL (ng/ml)	Interpretation	Situations observed in
3–30b	normal	non-pregnant female
10–400		pregnancy
2–20		postmenopausal female
25b-150	moderate elevation	● prolactinoma ● “stalk effect” (see text) ● other causesd
> 150c	significant elevation	prolactinomad
Note: ectopic sites of prolactin secretion have rarely been reported (e.g. in a teratoma) normal values vary, use your lab’s reference range  some authors recommend 200 ng/ml as the cutoff for probable prolactinomas14 d for DDx of hyperprolactinemia

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Hemangioblastoma

Table 41.5 Associations with von Hippel-Lindau disease
Common lesions	Frequency in VHL
hemangioblastomas
● cerebellum (solid or cystic)	80%
● retina	41–59%
● brainstem	10–25%
● spinal cord	10–50%
pancreatic tumors or cysts	22–80%
renal clear cell Ca & cysts	14–60%
polycythemia	9–20% of intracranial HGBs
Rare lesions (pertinent to nervous system)	Frequency in VHL
supratentorial hemangioblastoma	3–6%
cystadenomas of the broad ligament	10% of ♀
papillary cystadenomas of epididymis	25–60% ♂
endolymphatic sac tumors	10–15%
adrenal medullary pheochromocytoma (tends to be bilateral)	7–24%