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Young male with headache, blindness, and hypogonadism

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Q1: What are the abnormalities shown in skull radiograph (see p 513)?

The skull radiograph shows sutural diastases, beaten silver appearance, enlarged sella with sellar destruction, and suprasellar flocculonodular calcification.

The lesions producing suprasellar calcification are as shown in box 1.

Box 1: Suprasellar calcification: differential diagnosis

  • Craniopharyngioma

  • Pituitary adenoma

  • Hypothalamic germinomas

  • Meningioma

  • Dermoid tumours

  • Epidermoid

  • Aneurysm of internal carotid artery

  • Tuberculoma

  • Sarcoid granuloma

  • Oligodendroglioma

Box 2: Structural lesions of the hypothalamic-pituitary axis producing hypogonadotrophic hypogonadism1

Tumours

  • Pituitary adenomas

  • Craniopharyngiomas

  • Germinomas, gliomas, meningiomas

    Infiltrative disorders

  • Sarcoidosis

  • Haemochromatosis

  • Histiocytosis X

    Head trauma

    Radiation therapy

Q2: What is the diagnosis?

The diagnosis is hypogonadotrophic hypogonadism, secondary to a structural lesion of hypothalamus. The structural lesions of the hypothalamus can interfere with the normal pattern of gonadotrophin releasing hormone synthesis, secretion, or stimulation of gonadotropes. In view of features of raised intracranial tension, bilateral optic atrophy, hypogonadotrophic hypogonadism, childhood onset, and presence of suprasellar calcification most likely structural lesion is craniopharyngioma. Other structural lesions of the hypothalamic-pituitary axis producing hypogonadotrophic hypogonadism are depicted in box 2.

Q3: What are the various clinical presentations of this condition?

The clinical presentations of craniopharyngioma are as shown in box 3.

Box 3: Clinical presentations of craniopharyngioma2

Children

  • Hypopituitarism (growth hormone, thyroid stimulating hormone, corticotrophin, gonadotrophin deficiency)

  • Increased intracranial pressure due to hydrocephalus (80%)

  • Loss of vision and field defects (60%)

  • Short stature (7%–40%) and retarded bone age

  • Delayed sexual development (20%)

  • Diabetes insipidus

    Adults

  • Visual complaints (80%)

  • Papilloedema (15%)

  • Headaches (40%)

  • Mental deterioration or personality changes (26%)

  • Hypogonadism (35%)

  • Hyperprolactinaemia (33%–50%), usually <150 μg/l

  • Intellectual deterioration and dementia (30%)

  • Diabetes insipidus (15%)

  • Weight gain (15%)

  • Panhypopituitarism (7%)

  • Aseptic meningitis, inflammatory hypophysitis

Discussion

Craniopharyngiomas constitute 3%–5% of all intracranial neoplasms. Most of these are suprasellar, but about 15% are intrasellar. Rarely they may be found in the nasopharynx or the third ventricle. The peak incidence of craniopharyngiomas is between ages of 6 and 14 years. Although craniopharyngiomas are usually manifested in childhood, 45% of patients are over age 20, and 20% are over age 40 at the time of diagnosis.

Craniopharyngiomas arise from remnants of Rathke's pouch, which is the diverticulum of the roof of the embryonic oral cavity that normally gives rise to anterior pituitary. It is a congenital malformation present at birth and gradually grows over ensuing years. The tumour arises from rests of squamous cells at the junction of the adenohypophysis and neurohypophysis. It is usually well encapsulated and composed of cystic and solid components. It does not undergo malignant degeneration. It forms a cyst as it enlarges, which contains degenerated cells and may calcify. The calcifications may be microscopic or gross. The cysts may be multiloculated. The degenerative changes are associated with the deposition of cholesterol crystals that confer an oily appearance to the cyst fluid. This dark brown, oily fluid ranges from a “machinery oil” or “crank-case oil” to a shimmering cholesterol laden liquid. The presence of immunoreactive human chorionic gonadotrophin has been reported in cyst fluid of this neoplasm.3 There are two histological patterns of craniopharyngioma, adamantinomatous and papillary. The first is composed of lace-like strands of stellate epithelial cells with a basal pallisade enclosing many cystic spaces. The masses of eosinophilic, necrotic, keratinised cells that accumulate within the epithelium often become heavily calcified and may dominate the histology of a small biopsy. The less common papillary craniopharyngiomas usually occur in adults and are formed by mature squamous epithelial cells encasing a fibrovascular core.4This type does not calcify and only rarely invades the sella. The tumour cells are keratin immunoreactive, do not contain secretory granules on electron microscopy, and have characteristic bundles of tonofilaments and desmosomes. The tumour cells contain oestrogen receptor mRNA.5 The plain skull radiograph, computed tomogram, and magnetic resonance imaging scan features of craniopharyngioma are shown in box 4.

Box 4: Radiological features of craniopharyngioma2

Plain skull radiograph

  • Enlargement or distortion of sella.

  • Suprasellar calcification: flocculent, granular, nodular, or curvilinear (80%–90% children, 50% adults).

    Computed tomogram

  • Cystic component with ring or nodular calcification (most children and 80% adults).

  • Computed tomogram can reveal calcification not visible on a plain radiograph.

    Magnetic resonance imaging scan

  • Findings variable: some cysts resemble cerebrospinal (CSF), others less intense than CSF on T1 images but brighter than CSF on T2 images, some mimic subacute haemorrhage.

  • Varying signal intensities of mixed cystic and solid components (80%).

  • Areas of homogenous T1 hyperintensities and enhancement of solid and cystic components.

  • Calcification not usually visible on magnetic resonance imaging unless present in very large amounts.

Magnetic resonance imaging with contrast is the most sensitive diagnostic technique, allowing identification of cystic and solid components and delineation of the anatomic relationships necessary for a rational operative approach.6

The treatment is generally unsatisfactory. Complete surgical removal is often attempted but the recurrence rate is high. Tumours less than 3 cm in diameter have a better prognosis.2 The combination of limited tumour removal, and radiation therapy of large craniopharyngiomas leads to at least as satisfactory neurological prognosis and better cognitive and endocrinological outcome than attempts at complete surgical extirpation.7 The postoperative sequelae (more frequently seen with radical removal) are as in box 5.

Box 5: Postoperative sequelae in craniopharyngioma8

  • Hypopituitarism

  • Obesity and postoperative hyperphagia

  • Aberrant sleep pattern

  • Diabetes insipidus

  • Normal linear growth without growth hormone (the growth without growth hormone syndrome)

Follow up

The patient's magnetic resonance imaging scan showed a suprasellar tumour 6 cm2 in size with solid and cystic components, consistent with craniopharyngioma. A partial removal of the tumour revealed a craniopharyngioma of adamantinomatous pattern on histopathological examination. There was rapid relief in symptom of headache. The visual acuity has improved to perception of hand movements at a distance of 1 m in both eyes after four weeks. The patient is undergoing radiotherapy and is being followed up in endocrinology and neurosurgery clinics.

Final diagnosis

Craniopharyngioma presenting with hypogonadotrophic hypogonadism.

References

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