Diagnosis
Craniopharyngioma
Discussion
Introduction
Craniopharyngiomas
are intracranial tumors that are typically both cystic and solid in structure.
They are the second most common intra-sellar tumors. They occur most commonly
in childhood and adolescence and in later adult life after age 50 years.
Craniopharyngiomas are usually not discovered until they impinge upon
important structures around them, and are frequently quite large (over
3 cm) when detected. They are histologically benign tumors, but they have
a tendency to become adherent to structures in and around the pituitary
gland and pituitary stalk, including the optic nerves,
optic chiasm, intracranial arteries and the brain itself.
They
are thought to arise from remnants of the craniopharyngeal duct or Rathke's
pouch which are developmental structures related to the primitive gut.
Embryonic cells from an incompletely involuted craniopharyngeal duct or
transformation of squamous cells in the lower infundibulum or anterior
pituitary gland may give rise to a craniopharyngioma.
Symptoms
If
it compresses the pituitary stalk or involves the area of the pituitary
gland itself, the tumor can cause partial or complete pituitary hormone
deficiency. This frequently results in growth failure, delayed puberty,
loss of normal menstrual function or sexual desire, increased sensitivity
to cold, fatigue, constipation, dry skin, nausea, low blood pressure,
and depression. Pituitary stalk compression can also cause diabetes
insipidus and may increase prolactin levels causing galactorrhoea. If
the craniopharyngioma involves the optic tracts, chiasm, or nerves, then
visual disturbances can result. Involvement of the hypothalamus, an area
at the base of the brain, may result in diabetes insipidus.
Imaging
Features
The
characteristic CT findings of craniopharyngioma are a combination of hypodense
areas representing cysts and focal hyperdense areas representing calcification.
Calcification is less common in adults, compared to children. The cystic
component is common and can be quite extensive; it is only when these
tumors are solid and lack calcifiction and cystic areas that they are
difficult to differentiate from pituitary adenomas.
On
MR, the solid and cystic components are easily seen, with the solid component
isointense to brain on all pulse sequences, and tumor calcification seen
as a region of negligible signal intensity. The appearance of the cystic
component varies, depending on its protein component.
Treatment
The
initial treatment for a craniopharyngioma is usually surgery. The goal
of surgery is to completely remove the tumor while improving or at least
preserving pituitary, visual and brain function. When the tumor cannot
be completely removed, radiation treatment generally offers some degree
of tumor control and prolonged survival. Additionally, because of the
tendency for craniopharyngiomas to recur, repeat MRIs or CT scans should
be obtained at least once a year for the first several years after surgery
or radiation therapy.
Net
Links
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Dr.
Ashok Raghavan, Manipal Hospital, Bangalore
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