* Address correspondence to Marc J. Lacrampe, MD, Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 21^st and Garland Ave, Nashville, TN 37232-2675. Ph 615-322-0999 Fax 615-322-3764

Synonyms: None.

Prevalence: 2-5% of intracranial tumors, 50% of suprasellar tumors in children. Only 10 perinatal (congenital) cases have been described. M1:F1.75.

Definition: Benign midline suprasellar tumor containing fat, calcification and cystic components.

Etiology: Unknown.

Pathogenesis: Cushing believed that the tumor arose from cell rests derived from the craniopharyngeal duct. Others suggest that these tumors arose from remnants of Rathke"s pouch.

Associated anomalies: No consistent associations (see text).

Differential diagnosis: Teratoma, astrocytomas, optic chiasm and hypothalamic glioma, primitive neuroectodermal tumors and lipoma of the corpus callosum.

Prognosis: Very poor: only one of 10 previously reported congenital cases survived beyond one year of age.

Recurrence risk. After complete removal: 7%, higher after partial resection. Not known to be increased for subsequent pregnancies.

Management: When large, as for disease with fatal outcome.

MESH Craniopharyngioma ICD9 237.0 (Craniopharyngioma), 742.9 (Unspecified anomalies of the CNS)

Introduction

Craniopharyngiomas are benign tumors believed to be congenital, and ten cases of neonatal diagnosis of these tumors have been reported^7-10. To our knowledge, only one previous case of in utero diagnosis of craniopharyngioma has been recorded¹¹, and this mass was detected at 35 weeks gestational age. We present a case of congenital craniopharyngioma initially seen in a fetus at 26 weeks gestational age and not associated with hydrocephalus or polyhydramnios.

Case report

A 27-year-old white patient, G₄P₂₀₁₂, was referred for sono­graphic evaluation of her fetus. She had previously had a normal outside sonogram at 7 weeks. Maternal serum alpha-fetoprotein at 16 weeks was 43 ng/ml (median 33.7). A sonogram at 19 weeks reported minimal dilatation of fetal renal pelves and was otherwise normal. A follow-up exam at 26 weeks revealed an intracranial mass, and the patient was referred to our institution.

At our initial exam, a single fetus at 26 weeks gestational age (BPD, humerus, and femur) was seen. The presence of a brightly echogenic intracranial mass measuring 3.5 cm in diameter was confirmed. The mass was midline, inferior to the corpus callosum, and superior to the sella turcica (fig. 1-2).

Fig. 1: Echogenic midline mass at 26 week: coronal section.

Fig. 2: Sagittal appearance at 26 weeks. Note the absence of hydrocephalus.

Because of the location and the echogenicity, a presumptive diagnosis of lipoma of the corpus callosum was made. Hydrocephalus was absent, and the BPD within normal limits. No other abnormalities were seen. In retrospect, by reviewing the “baby-picture” tape that the patient had received at the referring institution, a 2 cm mass was visible on the examination performed at 19 weeks. Follow-up exams at 28 (fig. 3) and 33 weeks (fig. 4) showed a very rapid interval growth of the mass to 6 cm diameter.

Fig. 3: Repeat examination 12 days after the image on fig. 1. Considerable enlargement is visible.

Fig. 4: Last examination a month after fig. 3. 

The echotexture of the mass progressively became heterogenous. Some hypoechoic areas developed between areas of very dense echogenicity, probably representing calcifications. Because of the rapid growth of the lesion and the presence of calcifications, the diagnosis of lipoma was tentatively replaced with that of craniopharyngioma. No hydrocephalus was present, and fetal growth was appropriate. An amniocentesis performed at 34 weeks demonstrated a L/S ratio of 1.0. Labor began spontaneously at 36 weeks and a half weeks, and the infant delivered by cesarean section performed due to breech presentation.

The Apgar scores were 6 and 9 at 1 and 5 minutes. The infant, a 2960g girl, was admitted to the Neonatal Intensive Care Unit for respiratory distress. The head circumference was 35.8 cm (90th percentile). The craniofacial structure and fontanelles were normal, and mild hypertonia was noted. On the first day of life a head ultrasound exam confirmed the presence of a large, echogenic, partially cystic suprasellar mass (fig. 5).

Fig. 5: Postnatal US scan  at birth.

A CT scan on the third day of life revealed both calcification and focal areas of decreased density, suggesting fat within the mass (fig. 6). The respiratory distress was caused by hyaline membrane disease and resolved. Hypothalamic and endocrine functions were normal.

Fig. 6: CT scan at birth with high and low density regions.

A biopsy of the mass was performed on the eighth day of life; the result was epithelial neoplasm consistent with craniopharyngioma. After consultation with the neonatologists, neurosurgeons, and oncologists, the family decided that only supportive care would be administered. The patient was discharged at two and a half weeks of age. She was readmitted at 2 months of age for suspected sepsis. She showed no interval developmental progression. She had no visual attention and her pupils were non-reactive. She was globally hypertonic and had no purposeful movements. An MRI at this time (fig. 7) showed no change in size of the tumor. The patient was again discharged with supportive care only and expired several months later.

Fig. 7: MRI scan at 2 months.

Discussion

Brain tumors in the first year of life are predominantly supratentorial in location^1-3. Congenital brain tumors, as defined by Arnstein et al, are those tumors that produce symptoms before 2 months of age⁴. Teratomas are the most common congenital intracranial neoplasm^5-6. Congenital craniopharyngiomas are seen much less frequently, and there are few documented cases of these tumors^7-10. Only one previous in-utero detection of a craniopharyngioma has been reported¹¹. In a large study of midline supratentorial neoplasms from the University of Sao Paulo, of 1632 cases of intracranial neoplasms, 592 cases (36.2%) occurred in patients between 0 to 20 years. Of these, 3.5% were craniopharyngiomas, 1.35% hypophyseal neoplasms, and 6% pineal neoplasms²⁸. The prevalence of these tumors in the fetus in unknown. Only 30% of craniopharyngiomas occur in children less than 16 years old^24.

Etiology and pathogenesis

The origin of craniopharyngiomas is somewhat controversial. The term “craniopharyngiomas” is attributed to Cushing, who believed the tumor arose from cell rests derived from the craniopharyngeal duct¹². Erdheim hypothesized that these tumors arose from remnants of Rathke"s cleft, and recent reports have supported this theory^13-12.

Pathology

Craniopharyngiomas are histologically benign tumors composed of bands of stratified squamous epithelium separated by connective tissue¹⁴ or an adamantinous or a squamous papillary structure. In a series of over 100 craniopharyngiomas the following histopathology types were found. “The frequently solid (50%), always uncalcified squamous papillary tumor type was found in one third of the adult patients (greater than or equal to 20 years) but did not occur in children. It was associated with a good functional postoperative outcome (84.6%). There have been no cases of tumor recurrence in the squamous papillary group. However, in the group with the adamantinous type of craniopharyngioma, the recurrence rate was 13% in adult patients and 9% in children. When compared to the adult adamantinous cases, the incidence of visual deficits was lower in the squamous papillary group (75% vs. 84%) but the incidence of endocrine abnormalities was higher (75% vs. 52%). Thus, the preoperative, operative, and postoperative features of the two types of craniopharyngioma were found to be distinctly different in adults and children”²⁷. They are usually suprasellar in location, but some infrasellar cases have been reported¹⁵. Because of their location, these tumors may compress the optic chiasm and optic tracts or produce hypothalamic or pituitary dysfunction¹⁶ and hydrocephalus (from obstruction of the third ventricular cerebrospinal fluid outflow).

Symptomatology

Signs and symptoms commonly produced by these tumors in older children include: headache, vomiting, visual loss and papilledema, endocrine disorders including short stature, obesity, hypogonadism, and diabetes insipidus¹⁷.

Diagnosis

This case is the second documented case of in utero detection of a craniopharyngioma. The prenatal sonographic findings in both cases include a large, echogenic midline intracranial mass with suspected calcification. Hydrocephalus was absent in both case¹¹. Polyhydramnios was reported in the previous case but was not seen in this case. Polyhydramnios and hydrocephalus have been variable findings in other cases of prenatally diagnosed intracranial masses^2,5.

The CT appearance is that of a heterogenous suprasellar mass, often with non-uniform enhancement, and calcification is seen in 80% of cases¹⁸. The large size of these neonatal tumors is also a consistent finding⁷. Low-density cystic areas are reported in approximately 85% of cases, and these are frequently multilocular.

The MRI findings have been extensively reported, primarily in older patients. On T_1-weighted images the signal characteristics are variable, depending on the amount of cholesterol, keratin, and methemoglobin in the tumor, and range from CSF to fat-like intensity¹⁹. On T_2-weighted images, the masses are typically heterogeneous with high signal intensity. MRI, with the advantages of multiplanar imaging and high resolution, is the method of choice for evaluating the extent of these tumors and the degree of vascular encasement²⁰.

Associated anomalies

There have been no anomalies consistently reported in association with congenital craniopharyngiomas. In two cases low-set ears have been noted; polydactyly,  hypoplastic lung¹¹, centronuclear (myotubular) myopathy²⁵, or Moya-moya disease²⁶ have also been reported. There is a mild female predilection among the reported cases, with boy to girl ratio of 4:7.

Differential diagnostic

The primary differential diagnostic consideration of neonatal craniopharyngioma is a teratoma. This tumor occurs with greater frequency, is often suprasellar, large and contains calcification. The differential diagnosis between craniopharyngioma and teratoma in neonates is difficult radiologically, and biopsy is generally required to establish the diagnosis. Other neonatal intracranial neoplasms include astrocytomas, which may be suprasellar in location and in homogeneous in echotexture¹ and optic chiasm and hypothalamic glioma. Primitive neuroectodermal tumors and lipoma of the corpus callosum should also be considered.

Prognosis

Although these tumors are benign histologically, and can be cured if completely removed, the prognosis for neonatal craniopharyngioma is very poor. Only one of 10 previously reported cases survived beyond one year of age⁷. The usual massive size and critical location of these tumors makes complete surgically removal very difficult²¹ and accounts for this poor prognosis. Complete removal provides the best prognosis but cannot always be achieved. When partial removal is performed it is usually supplemented by radiation therapy in older pediatric patients²². In lesions discovered during childhood and treated by surgery and radiation therapy, 5-and 10-year survival rates of 90% and 80% have been described²³ but with a high morbidity (visual and endocrine deficits).

Recurrence risk

When complete resection can be performed (up to 90% in one series), there is a 7% risk of recurrence²¹. The risk of recurrence is much higher with partial resection. The risk of recurrence in subsequent pregnancies is not known to be increased: no familial cases have been reported.

Management

Because of the poor prognosis, termination of pregnancy can be offered if the diagnosis is suspected early enough. The difficulty of making a differential diagnosis with teratoma is of little concern, since either tumor has an extremely poor prognosis. Cesarean section does not appear indicated even if the fetal head is enlarged.

References

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