Bilateral nasal obstruction due to an intranasal craniopharyngioma

1. Introduction 

Craniopharyngiomas, while histologically benign, can be locally aggressive tumors. They are derived from the obliterated craniopharyngeal duct, Rathke's pouch (Fig. 1A and B). While some arise within the sella, most are found in the suprasellar region; a purely infrasellar craniopharyngioma is rare.

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Fig. 1. Sagittal view of an embryo showing Rathke's pouch in green, an epithelial diverticulum that arises during the fourth week of gestation from the oral stomodeum and invaginates superiorly towards the brain while diencephalic neuroectoderm descends. Cooperatively the two will form the pituitary gland. Inset B: Rathke's pouch eventually forms the anterior lobe and pars intermedia of the pituitary gland (shown in green). Incomplete resolution of the craniopharyngeal duct can result in cellular rests, which can give rise to purely infrasellar craniopharyngiomas. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

2. Case presentation 

A 14-year-old girl presented to our institution with a 1-year history of bilateral nasal obstruction, headaches, and syncopal episodes related to noseblowing. Physical examination during the initial office visit revealed a mass in the posterior aspect of her nasal cavities (Fig. 2A). A CT scan showed calcifications within the mass. A magnetic resonance imaging study confirmed the presence of an obstructing mass with extension into both the nasopharynx and posterior nasal cavities (Fig. 2B). Neither study demonstrated intracranial involvement. Intraoperative nasal endoscopy revealed a tan polypoid mass that was completely obstructing both nasal cavities. Gentle manipulation showed that it was soft and that it was pedunculated on the posterior septum. Being relatively avascular, the tumor was easily removed under endoscopic visualization using Blakesley and TruCut forceps. It measured 2.8cm in its greatest dimension. Histologic examination led to the diagnosis of an infrasellar adamantinomatous craniopharyngioma (Fig. 3). A 6-month postoperative surveillance MRI did not reveal tumor recurrence.

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Fig. 2. (A) Endoscopic view prior to excision of the right nasal cavity. (B) Coronal T1-weighted MRI.

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Fig. 3. Hematoxylin and Eosin slide, 20×: the tumor is composed of broad strands of squamous epithelium with peripheral palisading of the nuclei resting on a basement membrane, giving it a cyst like configuration. The “cysts” appear to be filled with an amorphous, eosinophilic, acellular material. There is abundant compact “wet keratin” and some areas that appear to be calcified. These features are consistent with an adamantinomatous craniopharyngioma.

3. Discussion 

Craniopharyngiomas are benign-appearing dysodontogenic epithelial tumors; over 96% of them affect intradural suprasellar anatomy. To our knowledge, there are over 40 reported cases of craniopharyngiomas with infrasellar involvement in the world literature; most of these had a sellar component. In contrast, there have only been eleven purely infrasellar, extracranial craniopharyngiomas reported in the literature (Table 1) [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11].

Table 1. Purely infrasellar, extracranial craniopharyngiomas at the time of presentation.

	Author/year	Age/sex	Symptoms	Location	Histology	Surgery	Radiation	Follow-up	Outcome
	Pheline/1981*	12 years/F	Headache, CN VI palsy, nasal obstruction	SS, NP, RP, IF NP, RP, IF	+ calcifications cystic/solid+calcifications	Sublabial transnasal (incomplete) then D	None	63 months*	Persistence, reoperated @ 54 mos.
	Lewin/1984	27 years/F	Epistaxis, headache	NC (vomer), NP	Cystic/solid? calcifications	TP	None	24 months	NED
	Ortiz/1988	20 years/M	Epistaxis, nasal obstruction	NPX	A+calcifications	Yes	None	–	NED
	Pharaboz/1989	27 years/F	Hyponasality/nasal obstruction	SS, NPX, NC, C	Cystic/solid+calcifications	Transnasal	–	–	–
	Byrne/1990	29 years/F	Nasal obstruction	NC, NPX, ES, SS, MS, C	A+calcifications	LR	Adjuvant	36 months	NED
	Gili/1991	9 years/M	Nasal obstruction, diplopia	NPX, SS, PA, C	–	Fisch type C	None	6 years	NED
	Bret/1993	16 years/F	Nasal obstruction	SS, NPX, NC, PPF, IF	Cystic/solid+calcifications	LeFort I Maxillectomy	None	14 months	NED
	Cheddadi/1996	1mo/F	Neonatal respiratory distress	NC, NP	–	Endo	None	31 months	NED
	Jiang/1998	7 years/M	Epistaxis	ES	Cystic/solid+calcifications	Endo	None	12 months	NED
	Deutsch/2001	8 years/M	Headache, visual loss	ES, SS	A+calcifications	BFC	Adjuvant	13 months	AWD
	Ahsan/2004	59 years/M	Epistaxis	NC, NPX, ES, SS, MS	P−calcifications	D	None	12 months	NED
	This report	14 years/F	Nasal obstruction, headaches, syncope	NC, NPX	A+calcifications	Endo	None	–	NED

Location: C-clivus; ES-ethmoid sinus; IF-infratemporal fossa; JF-jugular foramen; MS-maxillary sinus; NC-nasal cavity; NP-nasopharynx; SS-sphenoid sinus; PA-petrous apex; PPF-pterygopalatine fossa. Histology: A-adamantinomatous; P-papillary. Surgery: BFC-bifrontal craniotomy with subfrontal transbasal approach; D-sublabial Denker's medial maxillectomy and sphenoethmoidectomy; Endo-transnasal endoscopic; LR-lateral rhinotomy; TP-transpalatal; TPC-temporoparietal craniotomy. Outcome: AWD-Alive with disease; NED-No evidence of disease

* Pt was reoperated 54 months after an initial incomplete resection.

The overall incidence of craniopharyngiomas is approximately 0.13 per 100,000 person years and is not gender or race dependent. Craniopharyngiomas comprise approximately 1.5% to 11.6% of all intracranial tumors. A bimodal distribution places peak incidence rates in children (aged 5–14 years) and adults (aged 50–74 years). Approximately 338 cases of this disease occur annually in the United States, with 96 occurring in children from 0 to 14 years of age [12].

Craniopharyngiomas are thought to arise from the remnants of Rathke's pouch (Fig. 1). By the twelfth week of gestation, the craniopharyngeal duct, the cellular tract formed by the dorsal ascension of Rathke's pouch disappears, leaving an obliterated tract between the sphenoid cavity to the junction of the palate and posterior nasal septum [13]. Most craniopharyngiomas, however, occur in and/or above the sella turcica. Only occasionally do they develop in the basisphenoid or pharynx, presumably from rests of cells in an incompletely obliterated tract.

In 1904, Erdheim was the first to theorize that craniopharyngiomas arise from epithelial cell rests in partially involuted hypophyseal-pharyngeal ducts [14]. In 1931, Carmichael subsequently demonstrated epithelial remnants of the duct in the region of the pituitary gland in 33% of autopsies [15]. The histologic pattern of craniopharyngiomas is variable but recapitulates the enamel organ of the tooth, which explains their histologic similarity to ameloblastomas, tumors of the enamel organ cells [16], [17]. There are two predominant histologic types: adamantinomatous and papillary [18]. The adamantinomatous tumor classically appears as a cystic tumor with a solid component; ascribed as the pediatric variant, these typically occur in children but can occur in early adulthood. Calcifications are often noted on CT imaging. This subtype tends to be poorly encapsulated, with a propensity for inflammation and fibrosis, often leading to dense interdigitation of the surrounding tissues and vasculature. This increases the risks of recurrence, regardless of treatment modality. By contrast the adult type, the papillary variant, is typically a solid tumor without calcification; having greater encapsulation, this variant lends itself more readily to surgical excision. The predilection of these two variants for their respective age groups helps to explain the tumor's bimodal distribution.

The differential diagnosis of an infrasellar mass includes squamous cell carcinomas, nasopharyngeal carcinomas, adenoid cystic carcinomas, esthesioneuroblastomas, inverting papillomas, rhabdomyosarcomas, lymphomas, sarcoidosis, eosinophilic granulomas, tuberculosis, syphilis, juvenile nasopharyngeal angiofibromas, chordomas, Rathke cleft cysts, teratomas, dermoids, choristomas and encephaloceles.

Craniopharyngiomas’ symptomatology results from local expansion and impingement on surrounding structures; metastases from craniopharyngiomas are extremely rare. In the case of a purely infrasellar mass, nasal obstruction, epistaxis, sinusitis and headaches predominate. If there is a suprasellar/intracranial component, then visual field defects, varying degrees of pituitary insufficiency, and signs of increasing intracranial pressure may appear.

The work up should include general and neurologic examination (including visual field evaluation), a thorough nasal endoscopy, and both MRI/MRA and CT imaging, with and without contrast. CT imaging will often detect the calcifications found in the adamantinomatous variant as well as bony destruction and remodeling. MRI imaging best delineates soft tissue involvement and is particularly important to preoperative planning. If intracranial involvement is noted, an endocrine workup is indicated.

To date, there is no true consensus regarding the optimal treatment of craniopharyngiomas. In the case of uniquely infrasellar tumors, only case reports exist. It is therefore impossible to have true evidence-based recommendations regarding treatment and prognosis. From the gathered case reports of infrasellar tumors, the primary treatment has historically been complete surgical excision with or without postoperative radiation depending on the extent of the tumor. Needless to say, close postoperative surveillance is warranted for these rare tumors; it should include postoperative MRI surveillance at regulated intervals (3 months, 6 months, 1 year, 2 years). The surgical approach to an infrasellar craniopharyngioma is dictated by its location and extent. Lateral rhinotomy or endoscopic approaches can be used for tumors restricted to the confined to the nasopharynx and nasal cavity. For larger tumors, transphenoidal and transcranial trajectories may be necessary.

For intracranial tumors, though still controversial, radical excision is still considered the treatment of choice if the tumor's size and involvement with the surrounding tissue permits it [19]. If not, then subtotal resection is usually accompanied by radiation therapy; without radiation, recurrence rates may be as high as 73% and is likely to occur regardless of tumor variant [20], [21]. Some authors have reported success in treatment of cystic craniopharyngiomas with intracystic chemotherapeutic therapy with as bleomycin as well as intracavitary radiotherapy [22], [23], [24].

The 5-year survival rate for all craniopharyngiomas is approximately 80% and decreases with older age at the time of diagnosis [12]. Data collected for the National Cancer Data Base in the United States from 1985–1988 and from 1990–1992 revealed that the survival rate varied by age: patients younger than 20 years had a 99% survival rate at 5 years, while only 38% of those over 65 survived [12]. Tumor size may also influence survival rates. In one pediatric series, the size of tumor at the time of presentation correlated with risk of recurrence, five of six patients with tumors ≥5cm experienced recurrences while only 6 of 30 recurred when the tumor was ≤5cm [25]. Subtotal resection without radiation therapy is often associated with elevated recurrence as well.

4. Conclusion 

This case highlights an unusual cause of nasal obstruction. While purely infrasellar craniopharyngiomas are unusual, they should remain in the differential diagnosis of nasopharyngeal and nasal masses. A careful work up is critical to evaluate for intracranial involvement as is an endocrine work-up if intracranial involvement is suspected or confirmed.

Radical excision is the treatment of choice for an infrasellar craniopharyngioma. Consideration should be given to postoperative radiation, especially if the tumor is incompletely removed. Due to the likelihood of local recurrence (especially the adamantinomatous variant) close postoperative follow-up is warranted.