Primary Squamous Papillary-Type Craniopharyngioma in the Cerebellopontine Angle: Report of Two Cases

Miyakoshi A¹*, Kohno M¹, Sora S¹, Sato H¹ and Yokoyama M²

¹Department of Neurosurgery and Stroke Center, Tokyo Metropolitan Police Hospital, Japan

²Department of Diagnostic Pathology, Tokyo Metropolitan Police Hospital, Japan

*Corresponding author: Miyakoshi A, Department of Neurosurgery and Stroke Center, Tokyo Metropolitan Police Hospital, Japan

Received: January 20, 2017; Accepted: February 26, 2017; Published: February 28, 2017

Abstract

We report two rare cases of primary squamous papillary-type craniopharyngioma that developed in the Cerebellopontine (CP) angle. A 54-year-old woman and 26-year-old man were operated on for partially calcified CP angle tumors. One tumor showed is intensity and the other showed hyperintensity on T1-weighted magnetic resonance images. The small nodules of the tumors were the only part requiring contrast enhancement. The tumors were diagnosed neuropathologically as squamous papillary-type craniopharyngiomas. Although the most frequent tumors occurring in the CP angle are schwannomas, meningiomas and epidermoid cysts, the possibility of craniopharyngioma should be considered in cases in which the cyst exhibits hyperintensity in the T1-weighted magnetic resonance imaging scan, inhomogeneous contrast enhancement, and concomitant calcification in the computed tomography scan.

Keywords: Cerebellopontine angle; Ectopic craniopharyngioma; Squamous papillary type; Cerebellopontine angle tumor

Abbreviations

CP: Cerebellopontine; CT: Computed Tomography; MRI: Magnetic Resonance Imaging; MR: Magnetic Resonance; FLAIR: Fluid-Attenuated Inversion-Recovery

Introduction

Craniopharyngioma is a benign epithelial tumor that originates from the Rathke pouch and usually develops around the parasellarregion. By pathology the tumor is divided into two main types, the adamantinomatous type and squamous papillary type. In contrast to the usual parasellar location, primary craniopharyngioma developing in the Cerebellopontine (CP) angle is extremely rare, with only eleven cases reported to date [1-9]. Ten of these cases were of the adamantinomatous type and one was of the squamous papillary type [1-7,9]. Here, we report the neuroradiological findings from two additional cases of squamous papillary-type craniopharyngioma that developed in the CP angle and were isolated from the parasellar region.

Case Presentation

Case 1

A 54-year-old woman presented with hearing impairment and facial numbness on the left side. Additional symptoms included dizziness and a tendency to lean to the left when walking. Neurological examination revealed deafness in the left ear, left facial hyperesthesia, horizontal spontaneous nystagmus to the right and a positive Romberg sign.

A Computed Tomography (CT) scan identified a hyperdense mass with nodular calcified spots on the left CP angle (Figure 1a). Magnetic Resonance Imaging (MRI) revealed an extra-axial tumor, which showed high intensity on T1-weighted Magnetic Resonance (MR) images (Figure 1c) and low intensity in T2-weighted MR images (Figure 1b). The small nodule of the tumor was the only part requiring contrast enhancement (Figure 1 d).

Figure 1: A 54-year-old female patient with a squamous papillary-type craniopharyngioma in the left CP angle. (a) Axial plain CT image shows a hyperdense mass in the left CP angle with partial calcification. (b) Axial T2- weighted MRI image reveals a hypointense mass in the left CP angle. (c) The mass in the left CP angle shows high intensity in the axial plain T1-weighted MR image. (d) Nodular enhancement was observed in a contrast-enhanced axial MR image (red arrow). (e) Intraoperative photograph following tumor removal showing that the pituitary stalk is visible beyond the arachnoid membrane and does not make contact with the tumor. (f) No apparent residual tumor in a postoperative axial enhanced MR image. (g, h) The wall of the cyst consisted of squamous epithelium with a papillary structure. The tumor contained keratinous material, cholesterin crystal, and a fibrous inflammatory granuloma.

    
    
    Figure 1:  A 54-year-old female patient with a squamous papillary-type
craniopharyngioma in the left CP angle. (a) Axial plain CT image shows a
hyperdense mass in the left CP angle with partial calcification. (b) Axial T2-
weighted MRI image reveals a hypointense mass in the left CP angle. (c) The
mass in the left CP angle shows high intensity in the axial plain T1-weighted
MR image. (d) Nodular enhancement was observed in a contrast-enhanced
axial MR image (red arrow). (e) Intraoperative photograph following tumor
removal showing that the pituitary stalk is visible beyond the arachnoid
membrane and does not make contact with the tumor. (f) No apparent
residual tumor in a postoperative axial enhanced MR image. (g, h) The
wall of the cyst consisted of squamous epithelium with a papillary structure.
The tumor contained keratinous material, cholesterin crystal, and a fibrous
inflammatory granuloma.

The patient was therefore operated on via a lateral sub occipital approach. A cystic tumor was identified, with a rust-colored component being visible through the wall of the capsule. Following the opening of the cyst a motor oil-like fluid and semisolid component were drained. The 3^rd nerve and pituitary stalk were identified beyond the arachnoid membrane with neither showing any sign of contact with the tumor (Figure 1e).

Postoperative MRI revealed near-total resection of the tumor (Figure 1f). Neuropathology showed that the wall of the cyst was composed of squamous epithelium with a papillary structure (Figure 1g). In contrast, the tumor contained keratinous material, cholesterin crystal and a fibrous inflammatory granuloma (Figure 1h), and was diagnosed as a squamous papillary-type craniopharyngioma. Postoperatively, the patient’s hearing acuity, facial numbness and gait disturbance improved. No sign of recurrence has been observed on follow-up examination for six years.

Case 2

A 26-year-old man presented with facial numbness on the right side, dizziness and a tendency to lean to the left when walking. Neurological examination revealed decreased sensation on the right side of the face. A CT scan of the head showed a hypodense mass with a nodular calcification in the right CP angle (Figure 2a). MRI further identified a cystic extra-axial tumor that partially contained a solid component and was enhanced with gadolinium-containing contrast medium (Figure 2b-2d). The tumor was separate from the sella turcica and pituitary stalk (Figure 2b).

The patient was operated on via a lateral sub occipital and transmastoid-transtentorial approach. Retraction of the cerebellum revealed a cyst with a thin wall that contained a yellow-green fluid. After removal of the tumor we confirmed that it was not attached to the pituitary stalk by intraoperative findings. Additionally, postoperative MRI confirmed near-total removal of the tumor (Figure 2e). Neuropathology revealed that the wall of the cyst was composed of squamous epithelium with a papillary structure (Figure 2f), and that the tumor contained degenerated bone tissue, cholesterin crystal and foreign body-type granuloma (Figure 2g). The final diagnosis of the tumor was a squamous papillary-type craniopharyngioma. Postoperatively, the hypesthesia of the patient’s face improved. No sign of recurrence has been seen on follow-up examination for four years.

Figure 2: A 26-year-old male patient with a squamous papillary-type craniopharyngioma in the right CP angle. (a) Axial image from a plain CT scan reveals a hypodense mass with spotty calcification in the right CP angle. (b) Axial T2-weighted MR image shows a hyperintense cystic mass containing a solid component in the right CP angle. Tumor is separate from the pituitary stalk (red arrow). (c) Axial T1-weighted MR image shows that the mass in the right CP angle is isointense. (d) Partially enhanced tumor in the right CP angle as seen in a contrast-enhanced axial MR image. (e) No apparent residual tumor in a postoperative axial enhanced MR image. (f, g) Cyst wall consisting of squamous epithelium with a papillary structure, and tumor containingcholesterin crystal and a foreign body-type granuloma.

    
    
    Figure 2:  A 26-year-old male patient with a squamous papillary-type
craniopharyngioma in the right CP angle. (a) Axial image from a plain CT
scan reveals a hypodense mass with spotty calcification in the right CP
angle. (b) Axial T2-weighted MR image shows a hyperintense cystic mass
containing a solid component in the right CP angle. Tumor is separate from
the pituitary stalk (red arrow). (c) Axial T1-weighted MR image shows that
the mass in the right CP angle is isointense. (d) Partially enhanced tumor in
the right CP angle as seen in a contrast-enhanced axial MR image. (e) No
apparent residual tumor in a postoperative axial enhanced MR image. (f, g)
Cyst wall consisting of squamous epithelium with a papillary structure, and
tumor containingcholesterin crystal and a foreign body-type granuloma.

Discussion

Craniopharyngioma is known to arise around the sella turcica, with the origin thought to be a remnant of the craniopharyngeal duct. Primary craniopharyngioma developing in the Cerebellopontine (CP) angle is extremely rare, with only eleven cases reported to date [1-9]. Ectopic craniopharyngiomas are extremely rare, with only several case reports describing ectopic craniopharyngiomas developing in the CP angle, sphenoid bone [10], third ventricle [11,12], nasopharynx [13,14] and clivus [15]. This pattern raises the possibility that ectopic craniopharyngiomas might develop from migrated squamous epithelial cell remnants originally derived from the craniopharyngeal duct.

Most tumors of the CP angle are schwannomas, meningiomas, and epidermoid cysts [16], with atypical CP angle tumors rarely reported, apart from craniopharyngioma, choroid plexus papilloma, and ganglioglioma [17-20].

Table 1 shows a summary of reported CP angle craniopharyngiomas. Including the two cases reported here, only 13 cases of CP angle Craniopharyngioma have been reported to date [1- 9]. Calcification was identified via CT scan in 6 of the 13 cases.

Table 1: Summary of previous reports of CP angle craniopharyngioma.




  
    Year 
    Author 
    Age,    sex 
    CT    findings 
    MRI    findings 
    Pathology 
  
  
    Density
    Calc 
    T1 
    T2 
    Enhanced 
  
  
    1990 
    Gokalp    HZ et al. 
    17, F 
    Hypo 
    N 
    - 
    - 
    - 
    Ad 
  
  
    2002 
    Link ML    et al. 
    29, M 
    Hyper 
    Y 
    Mixed 
    Mixed 
    Heterogeneous 
    Ad 
  
  
    2006 
    Aquilina    K et al. 
    31, M 
    - 
    - 
    Iso 
    - 
    Peripherally 
    Ad 
  
  
    2007 
    Powers    CJ et al. 
    12, F 
    - 
    - 
    Iso 
    Hyper 
    - 
    Ad 
  
  
    2009 
    Yan Y    et al. 
    54, F 
    Hyper 
    Y 
    Hypo 
    Mixed 
    Homogeneous 
    Ad 
  
  
    2011 
    Bozbuga    M et al. 
    34, M 
    Hyper 
    Y 
    Hyper 
    Hypo 
    Homogeneous 
    Ad 
  
  
    2012 
    Khalatbari    MR et al. 
    40, M 
    - 
    - 
    Hypo 
    Hyper 
    Peripherally 
    Ad 
  
  
    2012 
    Khalatbari    MR et al 
    22, M 
    - 
    - 
    Mixed 
    Mixed 
    Heterogeneous 
    Ad 
  
  
    2012 
    Khalatbari    MR et al. 
    28, M 
    - 
    - 
    Hyper 
    Hypo 
    Peripherally 
    Ad 
  
  
    2012 
    Sharma    M et al. 
    26, M 
    Hyper 
    - 
    Hypo 
    Hypo 
    No 
    Sq 
  
  
    2014 
    M S Kim    et al. 
    31, M 
    Hyper 
    Y 
    Hyper 
    Hypo 
    Peripherally 
    Ad 
  
  
    2017 
    Present    case 1 
    26, M 
    Hypo 
    Y 
    Iso 
    Hyper 
    Partially 
    Sq 
  
  
    2017 
    Present    case 2 
    54, F 
    Hyper 
    Y 
    Hyper 
    Hypo 
    Partially 
    Sq 
  
  
    M: Male; F: Female; Calc: Calcification; Y: Yes; N: No;    Ad: Adamantinomatous type; SqSquamous papillary type; -: not described



Table 1: Summary of previous reports of CP angle craniopharyngioma.

CT scans commonly identify calcification, as in ordinary craniopharyngiomas. The calcification we observed has also been reported in meningiomas, choroid plexus papilloma and ganglioglioma. In contrast, few reports have described calcification in vestibular schwannomas [21]. Four of the 13 cases of CP angle craniopharyngioma showed hyperintensity on the T1-weighted MR image, which reflects the cystic component containing a high concentration of protein in parasellar craniopharyngiomas [22,23]. In contrast, typical CP angle tumors such as schwannoma, meningioma and epidermoid cysts show is intensity or hypointensity on the T1-weighed MR image except for schwannomaor meningiomas with concomitant intratumoral hemorrhage. MRI findings are not uniform in CP angle craniopharyngiomas and show a variety of pattern enhancements (Table 1). In contrast to typical meningiomas and schwannomas, CP angle craniopharyngiomas are not uniformly enhanced. The possibility of craniopharyngioma should therefore be taken into account in cases where the cyst displays hyperintensity in the T1-weighted MRI scan, inhomogeneous contrast enhancement, and concomitant calcification in the CT scan.

Previously reported ectopic craniopharyngiomas were mostly of the adamantinomatous type [1-6,8-15]. Our two cases of squamous papillary-type craniopharyngioma are therefore extremely rare.

Conclusion

Although the most frequent tumors occurring in the CP angle are schwannomas, meningiomas and epidermoid cysts, the possibility of craninopharyngioma should be considered in cases in which the cyst exhibits both hyperintensity in the T1-weighted magnetic resonance imaging scan, with inhomogeneous contrast enhancement, and concomitant calcification in the computed tomography scan.

References

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Citation: Miyakoshi A, Kohno M, Sora S, Sato H and Yokoyama M. Primary Squamous Papillary-Type Craniopharyngioma in the Cerebellopontine Angle: Report of Two Cases. Austin Neurosurg Open Access. 2017; 4(1): 1054.

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