Clinical Characteristics and Surgical Management of Symptomatic Trans-sellar Encephalocele: Two Case Reports and a Review of the Literature

Abstract

Trans-sellar encephalocele is a rare subtype of basal encephalocele characterized by herniation of neural tissue through a defect in the sellar floor, extending into the sphenoid sinus or nasopharynx. Due to its deep anatomical location and proximity to critical neurovascular and endocrine structures, trans-sellar encephalocele presents significant diagnostic and surgical challenges. We report two adult cases of symptomatic trans-sellar encephalocele with progressive visual impairment, both successfully treated via endoscopic endonasal surgery. In addition, to contextualize these cases, we conducted a comprehensive literature review of 47 previously reported symptomatic trans-sellar encephalocele that was surgically treated in the neurosurgical field over the past quarter century, resulting in a total 49 patients (33 males, 16 females). Clinical characteristics, imaging findings, surgical approaches, and outcomes were analyzed. Of the 49 patients, the common symptoms included nasal obstruction (59.2%), endocrine dysfunction (46.9%), cerebrospinal fluid leakage (30.6%), and visual impairment (24.5%). The majority (69.4%) were diagnosed at age six or younger. Surgery was performed primarily via transnasal approaches (49.4%). Outcomes were available in 44 cases; 81.8% experienced symptom resolution or improvement. In our two cases, postoperative imaging confirmed the reduction of the trans-sellar encephalocele and cessation of cerebrospinal fluid inflow. Visual symptoms improved without recurrence or complications. Early diagnosis and tailored surgical intervention are essential for optimizing outcomes in trans-sellar encephalocele. The endoscopic endonasal approach enables safe and effective reduction of the trans-sellar encephalocele while preserving critical structures. Modifying of cerebrospinal fluid dynamics appears to play a key role in halting symptom progression. Long-term follow-up and further studies are warranted to establish standardized management strategies.

Introduction

Trans-sellar encephalocele (TSE) is a rare subtype of basal encephalocele, characterized by congenital bone and dural defects in the skull base at the level of the sella turcica, often extending into the nasopharyngeal region. Encephaloceles are a form of cranial bifidum and result from neural tube closure defects during embryogenesis, typically around gestational weeks 3 to 4. Basal encephaloceles are generally classified into six distinct anatomical subtypes: spheno-ethmoidal, trans-sphenoidal, trans-sphenoidal trans-sellar, spheno-orbital, trans-ethmoidal, and spheno-maxillary.^1-3) In addition to symptoms caused by mass effect, TSE may present with a variety of manifestations related to the involvement of structures in the parasellar region. These lesions present considerable neurosurgical challenges due to their proximity to critical anatomical structures, including the optic chiasm, hypothalamic-pituitary axis, circle of Willis, and cavernous sinuses.⁴⁾ Preservation of the contents within the encephalocele sac is vital to prevent further neurological or endocrine compromise, making TSE one of the most technically demanding conditions to manage surgically. Moreover, its deep anatomical location and frequently subtle clinical presentation render diagnosis particularly difficult. Delayed recognition can result in progressive visual impairment, endocrine dysfunction, and increased surgical morbidity. Therefore, early diagnosis and the implementation of an appropriate surgical strategy are essential for optimizing patient outcomes.^1-3) Despite advances in surgical techniques, the optimal management strategy for TSE remains undefined due to its extreme rarity.

In this report, we present two cases of symptomatic TSE associated with progressive visual impairment and review 47 previously reported cases of symptomatic TSE that were surgically treated in the field of neurosurgery over the past quarter century.^5-24) We describe the key clinical features, imaging findings, surgical techniques, and postoperative outcomes of all 49 cases. Our objective is to contribute to the growing body of knowledge regarding the diagnosis and surgical management of this rare and challenging neurosurgical condition.

Materials and Methods

We examined two cases of symptomatic TSE associated with progressive visual impairment ―a 26-year-old woman and a 32-year-old man―both of whom underwent transnasal surgery performed by the corresponding author (Amano K.). In addition, we performed a comprehensive review of 47 previously reported cases of surgically treated symptomatic TSE in the neurosurgical literature over the past quarter century. A total of 49 cases were analyzed in this study (Table 1).

Table 1.

Summary of surgically treated 49 symptomatic trans-sellar encephaloceles: A review of 47 reported cases and 2 present cases

Author/Year (Reference)	Case	Age/Gender			Symptoms						Surgery(Trans-)	Outcome
					BD/NO	ED	CSFL/M	VI	CNP	FD
Tsutsumi/1999 (5)	1	6	yo	/M		+	+	+			C	Transient DI
	2	3	mo	/M	+						C	Transient DI
Abe/2000 (6)	3	53	yo	/F			+				N	Repaired
	4	26	yo	/F		+		+	+		N	No change
Formica/2002 (7)	5	8	mo	/F	+			+			P	/
Sharma/2002 (8)	6	5	mo	/M	+						P	Death (meningitis)
	7	14	mo	/M	+						N	Symptom dissapeared
Faggin/2009 (9)	8	2	day	/M	+						N + O	Transient DI
Sasani/2009 (10)	9	26	yo	/M			+	+			N	CSFL stopped
Spacca/2009 (11)	10	14	mo	/M	+	+					C + P	ED improved after second surgery
	11	18	yo	/M		+		+			P	VI & ED improved
	12	3	yo	/F	+	+			+		N	BD improved
	13	14	yo	/F	+	+			+		N	BD & ED improved
	14	9	yo	/M		+	+				P	CSFL stopped
Rathore/2011 (12)	15	5	mo	/M	+					+	P	Death
	16	14	yo	/M	+						N	Not improved
	17	4	yo	/M			+				N	/
	18	16	mo	/M	+					+	P	/
Kumar/2011 (13)	19	1	mo	/M	+					+	P	/
Saito./ 2012 (14)	20	36	yo	/M	+	+		+			N	VI improved
Ogiwara/2013 (15)	21	2	mo	/M	+						O/P	GHD
	22	2	mo	/F	+						O/P + C	Recurrence, GHD
	23	3	yo	/F			+				O/P	CSFL stopped
	24	2	mo	/F		+					O/P	Stable
	25	1	yo	/M	+	+					O/P + C	Recurrence
	26	5	yo	/M		+					O/P + C	Stable
	27	6	mo	/F	+		+				O/P	BD improved & CSFLstopped
Sanjari/2013 (16)	28	17	yo	/M		+	+		+		N	CSFL stopped
	29	45	yo	/F			+				N	Recurrence, lumboperitoneal shunt
Yang/2015 (17)	30	3	yo	/M	+	+			+		N	VI & BD improved
	31	5	yo	/F		+					N	ED improved
	32	2	yo	/M		+	+	+			N	VI & BD improved, CSFL stopped
	33	17	yo	/M		+	+	+			N	VI & ED improved, CSFL stopped
	34	6	yo	/M	+	+		+			N	VI & ED improved
Zeinalizadeh/2017 (18)	35	18	mo	/F	+						N	BD improved
	36	24	mo	/M	+	+				+	N	Weight gain to normal levels
	37	8	mo	/F	+						N	BD improved
Bhaisora/2018 (19)	38	18	mo	/M		+					C	/
Rajasekar/2019 (20)	39	5	yo	/F			+				N	CSFL stopped
Morota*/ 2020 (21)	40	7	yo	/M	+		+				O/P + C	Died, unrelated to surgery
	41	4	mo	/M	+						O/P	Symptoms resolved
	42	1	yo	/M	+						O/P	Symptoms resolved
	43	1	mo	/F	+						O/P	Symptoms resolved
	44	25	day	/M	+		+				O/P	Symptoms resolved
Pavanello/2021 (22)	45	6	yo	/M				+			N	ED
Azab/2022 (23)	46	15	yo	/M		+	+				N	CSFL stopped
Basheer/2023 (24)	47	4	mo	/M	+	+					C	BD improved
Present cases First	48	26	yo	/F	+	+		+	+		N	VI & BD improved
Second	49	32	yo	/M		+		+			N	VI improved

*: Excluding cases that overlap with Ogiwara et al, /: not mentioned, CSF: Cerebrospinal fluid, DI: diabetis insupidus, GHD: Growth hormone deficiency, BD: Breathing Difficulties, NO: Nasal obstruction, ED: Endocrine Dysfunction, CSFL: CSF Leakage, M; Meningitis, VI: Visual Impairment, CNP: Cranial Nerve Palsy, FD: Feeding Difficulties, C: Cranial, P: Pratal, O: Oral, N: Nasal

Informed consent was obtained from all the patients. This study was approved by the Human Investigation Committee of Tokyo Women's Medical University (2021-0063) and Hamamatsu University School of Medicine (20-279) and performed in accordance with the Declaration of Helsinki.

Case Presentation

First case (case 48 in Table 1)

A 26-year-old woman presented with progressive visual impairment and nasal obstruction. She had experienced poor vision in her right eye since infancy and had a history of congenital cranial abnormalities, including a TSE, which had been monitored by a pediatrician since early childhood. At the age of 17 years, she was diagnosed with primary amenorrhea and initiated on hormone replacement therapy (Kaufmann regimen) for hypogonadotropic hypogonadism. Over the subsequent years, the patient developed worsening polydipsia, polyuria, and xerostomia, leading to a diagnosis of central diabetes insipidus, for which she was treated with desmopressin. At the age of 24 years, she developed anosmia, followed by progressive bilateral nasal obstruction. Six months later, she experienced further progression of visual field defects and photophobia in her left eye and was referred to our clinic. Endocrinological evaluation revealed hypogonadism and growth hormone deficiency. Preoperative magnetic resonance imaging (MRI) demonstrated a TSE herniating inferiorly into the nasopharyngeal cavity, causing displacement of the optic nerves (Fig. 1a and b). Computed tomography (CT) revealed a large defect in the sella turcica (Fig. 1c and d). Constructive interference in steady state (CISS) MRI showed bending of the optic nerves in the direction of the presumed cerebrospinal fluid (CSF) flow (Fig. 1e and f). Goldmann perimetry revealed left hemianopsia and severely impaired vision in the right eye (Fig. 1g and h). Preoperative endocrinological examination demonstrated severe growth hormone deficiency, hypogonadism, and diabetes insipidus (Supplementary Table 1).

Fig. 1.

First case (case 48 in Table 1).

Preoperative coronal (a) and sagittal (b) gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) revealed a trans-sellar encephalocele. Sagittal bone-window computed tomography (CT) (c) and three-dimensional CT (d) demonstrated a large defect in the sella turcica. Constructive interference in steady state (CISS) MRI in coronal (e) and sagittal (f) T2-weighted images showed optic nerve deformation, bending in the direction of presumed cerebrospinal fluid (CSF) flow (arrow). Visual field deficit in the Goldmann perimetry and bilateral visions before surgery (g and h).

An approach along the nasal septal bone toward the sphenoid sinus revealed the absence of the anterior wall of the sphenoid bone, providing direct access to the encephalocele. The lesion was covered with thick mucosa and exhibited firm adhesions to the surrounding mucosa within the sphenoid sinus. Circumferential dissection was performed with concurrent mucosal coagulation.

A transverse incision was made at the inferior margin of the encephalocele, exposing an underlying fatty layer, followed sequentially by the dura mater and the arachnoid membrane. Upon incision of the arachnoid membrane, CSF drained vigorously. Endoscopic inspection within the encephalocele revealed a deep third ventricle. To achieve closure, autologous fat harvested from the abdomen was inserted into the cavity and sutured in place with nylon thread to ensure a watertight seal. Additional circumferential coagulation was applied to further shrink the encephalocele. Further reduction was achieved by threading the inferior edge, retracting it upward, and securing it with sutures (Fig. 2a-d).

Fig. 2.

First case (case 48 in Table 1).

Intra-operative views demonstrated the encephalocele detached from surrounding sphenoid sinus mucosa (a), the dura (triangle) exposed after cutting the mucosa (b), the inside of encephalocele (c), and closure of the encephalocele was achieved by suturing after insertion of an abdominal fat graft (d). Postoperative gadolinium-enhanced T1-weighted MRI in the coronal (e) and sagittal (f) planes revealed a reduced encephalocele and a patent nasal cavity (↔). Visual fields assessed by Goldmann perimetry and bilateral visual acuity after surgery (g and h).

Postoperative MRI demonstrated a reduction in the size of the encephalocele and an opened nasal cavity (Fig. 2e and f). Goldmann perimetry showed slight improvement in the visual field deficit (Fig. 1g and h and Fig. 2g and h). Postoperative endocrinological examination demonstrated severe growth hormone deficiency, hypogonadism, and diabetes insipidus (Supplementary Table 1). The patient was able to breathe through her nose, her sense of smell was restored, progression of the visual field impairment ceased, and photophobia resolved.

She remained on hormone replacement therapy due to persistent pituitary dysfunction; however, her requirement for desmopressin decreased significantly. Notably, she conceived naturally and delivered a healthy child five years after surgery. The TSE remained reduced in size for 14 years postoperatively.

Second case (case 49 in Table 1)

A 32-year-old man was admitted with complaints of progressive right eye hemianopia. Six months before admission, he began experiencing blurred vision in his right eye. His left eye had been functionally blind since childhood, retaining only light perception. His visual impairment gradually worsened, significantly interfering with daily activities. Preoperative endocrinological evaluation revealed severe growth hormone deficiency and reduced antidiuretic hormone levels (Supplementary Table 1). The patient exhibited no signs of CSF leakage, meningitis, or nasal obstruction. Preoperative MRI and CT revealed a defect in the sellar floor and a TSE protruding into the nasopharynx, partially covered by fat (Fig. 3a-e). Cine MRI demonstrated CSF flow into the lesion (Fig. 3f). Goldmann perimetry confirmed right hemianopia (Fig. 3g).

Fig. 3.

Second case (case 49 in Table 1).

Preoperative coronal gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) with fat suppression (a), coronal T1-weighted MRI (b), sagittal gadolinium-enhanced T1-weighted MRI (c), sagittal T2-weighted MRI (d), sagittal computed tomography (CT) with a bone window (e), and cine MRI (f) revealed a trans-sellar encephalocele. The encephalocele was protruding into the nasopharynx, covered with fat (asterisk), and showed cerebrospinal fluid (CSF) flow into it (arrow). Right visual field assessed by Goldmann perimetry and visual acuity before surgery (g).

Removal of the anterior sphenoidal wall exposed the encephalocele, which was covered by mucosa. After peeling off the mucosal membrane, an underlying thick fatty layer was revealed. An incision was made in the fat at the inferior aspect of the sphenoid sinus, and the portion protruding into the nasopharynx was detached. The medullary cavity of the detached encephalocele remained intact because it was covered with the previously peeled mucosal flap and displaced superiorly. A new sella turcica was reconstructed by supporting the ventral surface of the displaced encephalocele with five or more bone fragments harvested from the nasal septum and anterior sphenoidal wall (Fig. 4a-c).

Fig. 4.

Second case (case 49 in Table 1).

Intraoperative endoscopic views showed the encephalocele covered with fat (asterisk) (a), separated from the portion (star) protruding into the nasopharynx (b), and supported by autologous septal bone (triangle) (c). Postoperative sagittal computed tomography (CT) with a bone window (d), coronal T2-weighted MRI (e), sagittal T2-weighted MRI (f), and cine MRI (g) demonstrated a reduced encephalocele, a newly constructed sellar floor (triangle), and absence of cerebrospinal fluid (CSF) flow into the encephalocele (arrow). Right visual field on Goldmann perimetry at 3 months postoperatively (h).

Partial improvement of right hemianopsia was observed (Fig. 4h), and postoperative endocrinological evaluation revealed severe growth hormone deficiency and reduced antidiuretic hormone levels (Supplementary Table 1). No other postoperative complications occurred. Postoperative CT and MRI confirmed the reconstruction of the sellar floor, reduction in size of the encephalocele, and absence of CSF flow into the lesion (Fig. 4d-g). The reduced size of the TSE was maintained for at least six months postoperatively.

Results

The clinical characteristics, surgical approaches, and outcomes of 49 TSE cases are summarized in the Table 1.

Patient distribution

Of the 49 patients, 33 were male and 16 were female, with ages ranging from 2 days to 61 years. Thirty-four patients (69.4%) were under 6 years of age, reflecting a predominance of juvenile cases.

Symptoms

The presenting symptoms, listed in order of prevalence (Table 1), were as follows: breathing difficulties or nasal obstruction in 29 patients (59.2%); endocrine dysfunction in 23 patients (46.9%); CSF leakage or meningitis in 15 patients (30.6%); visual impairment in 12 patients (24.5%); symptoms suggestive of cranial nerve palsy, including abducens nerve palsy, nystagmus, strabismus, exotropia, and photophobia in six patients (12.2%); and feeding difficulties in four patients (8.2%).

Surgical methodology

Among the 49 patients with TSE who underwent surgical treatment, the most commonly used approaches were transnasal (24 cases, 49%), transoral/palatal (8 cases, 16.3%), transpalatal (7 cases, 14.3%), transcranial (4 cases, 8.2%), combined transoral/palatal and transcranial (4 cases, 8.2%), combined transcranial and transpalatal (2 cases, 4.1%), and combined transnasal and transoral (2 cases, 4.1%).

Postoperative outcomes

Among the 49 patients who underwent surgical treatment, outcomes were reported for 44 cases: three patients died, three recurred, two showed no change, and 36 experienced showed symptom resolution or improvement.

Discussion

TSE is a rare cranial base defect characterized by the herniation of brain tissue and/or meninges through the sellar floor into the sphenoid sinus and/or nasopharyngeal region.^1-3) We encountered two cases of TSE with progressive visual impairment, both of which were surgically treated by the corresponding author. In this study, we reviewed 47 previously reported cases of surgically treated symptomatic TSE over the past quarter century in the field of neurosurgery and analyzed their clinical features, pathophysiological mechanisms, surgical approaches, and outcomes, together with our two additional cases, yielding a total of 49 patients (Table 1). Based on this analysis, we discuss the disease's pathogenesis and propose a treatment strategy.

Patient distribution

Given that TSE is fundamentally a congenital condition and considering that both of our cases were almost blind in one eye since infancy, the timing of diagnosis appears to vary widely among patients. This variability likely depends on when symptoms become noticeable or are discovered incidentally. In the absence of characteristic facial anomalies, diagnosis may be delayed until adolescence or even adulthood.¹²⁾ In addition, asymptomatic cases are presumed to remain undetected and latent.

Symptoms and mechanisms

Breathing difficulties, nasal obstruction, and feeding difficulties are considered to result from mass effect due to space-occupying lesions caused by the TSE. CSF leakage may be attributable to the absence of rigid structural support and underlying bony defects.

The pathophysiology of visual impairment is likely related to mechanical and dynamic effects associated with CSF flow into the TSE. Herniation of brain tissue and CSF pulsations may exert traction on the optic chiasm and optic nerves. Over time, this sustained CSF-mediated traction can result in progressive visual deterioration through deviation and stretching of the optic nerves. A similar mechanism is seen in empty sella syndrome, where increased CSF pulsation leads to optic nerve distortion and dysfunction.²⁵⁾ These altered CSF dynamics and intracranial pressure gradients are thought to contribute to the progression of visual impairment.²⁾ Fundoscopic examination revealed optic nerve atrophy in the affected eye, underscoring the critical importance of early diagnosis because prolonged traction on the optic nerves can lead to irreversible visual loss. This aligns with previously reported cases where prolonged chiasmal distortion led to irreversible optic neuropathy.²⁶⁾ Notably, had both of our patients been diagnosed and treated at an earlier stage, visual function loss in the contralateral eye might have been prevented.

The observed endocrine dysfunction is thought to result from the same mechanism as the visual impairment―namely, displacement and stretching of the pituitary gland and stalk into the TSE due to CSF flow and pulsation. Similarly, the cranial nerve palsies associated with TSE―such as abducens nerve palsy, nystagmus, strabismus, exotropia, and photophobia―appear to arise from a mechanism distinct from that observed in pituitary tumors.²⁷⁾ Rather than resulting from direct compression by a mass lesion, these symptoms are likely attributable to stretching of the cranial nerves induced by CSF pulsation.

Neuroimaging and diagnostic challenges

TSE presents significant diagnostic challenges due to its deep anatomical location and a variety of symptoms. Advances in imaging techniques, CT, and MRI have greatly improved diagnostic accuracy.^21,22) CT with bone window settings and three-dimensional reconstruction allows detailed visualization of bony defects and skull base anomalies. MRI is essential for assessing brain abnormalities, evaluating the contents of the encephalocele, and guiding surgical planning by identifying critical neural structures that must be preserved during intervention.²³⁾ MRI provides superior delineation of herniated neural tissue, CSF dynamics, and optic nerves displacement. High-resolution MRI using CISS sequences offers excellent contrast between CSF and soft tissues,²⁸⁾ enabling precise identification of the encephalocele sac.

In our cases, case 48 represents a myelo-meningo-cystocele associated with spinal dysraphism due to herniation of the third ventricle, whereas case 49 is classified as a lipo-myelo-meningo-cystocele because of the associated lipoma migration. MRI revealed inferior displacement of the optic nerves (Fig. 1a, b, e, and f and Fig. 3a and b), and cine MRI further demonstrated CSF inflow into the TSE (Fig. 3f), supporting the hypothesis that prolonged mechanical stress contributes to the development of optic neuropathy. These imaging findings were crucial for surgical planning and played an important role in evaluating postoperative outcomes and symptom improvement.

Surgical methodology

The goals of surgery include reducing the herniated encephalocele to alleviate compression on surrounding structures, repairing the skull base defect to prevent recurrence and CSF leakage, and preserving critical neural structures, such as the optic pathways and hypothalamic-pituitary axis.²⁴⁾ In our two cases, the surgical objectives were to reduce the size of the TSE and to alter the CSF flow into the encephalocele. We considered the primary aim of surgery not to be complete anatomical normalization of the TSE but rather symptom improvement or stabilization of disease progression.

The size of the TSE and its direction of progression are critical factors in determining the most appropriate surgical approach. The transnasal route, commonly used in pituitary surgery, was deemed optimal due to its ability to achieve surgical objectives with minimal invasiveness. Consequently, the decision to use the transnasal approach may heavily depend on the surgeon's experience with pituitary surgery.

In the conventional transcranial approach that was previously common, the TSE was resected at the anterior skull base (above the sella turcica). The unique feature of our method is the application of an endoscopic endonasal approach adapted from pituitary surgery techniques. This change in approach allowed us to visualize the entire TSE extending inferiorly, circumferentially dissect it from surrounding structures, and reduce its size without damaging the membrane covering it, which might contain neural or pituitary tissue.

Furthermore, incising and opening the TSE, with direct manipulation of the fragile optic nerves or the normal pituitary gland, may carry significant risks, potentially unleashing a “Pandora's box” that could exacerbate the patient's symptoms. Clearly, it is best left unopened unless absolutely necessary. In both of our cases, the primary complaint was progressive visual deterioration, and the main surgical objective was to halt this progression. Based on our hypothesis, the visual impairment was caused by CSF flow into the TSE, leading to traction on the optic nerves. Accordingly, altering this CSF flow became the central therapeutic target.

The nature of the membrane forming the TSE―whether arachnoid, neural tissue, or pituitary tissue―could not be clearly determined from preoperative imaging. In case 1, incision of the membrane revealed that, apart from the nasal mucosa covering the lesion, it consisted only of dura mater and arachnoid. It remained uncertain whether neural or pituitary tissue was included. Therefore, whenever possible, we consider it preferable to reduce the size of the TSE without incising it, thereby avoiding CSF leakage. This principle guided our decision in case 2, where the TSE was reduced in size solely by circumferential dissection from surrounding structures without incision.

We generally believe that rigid reconstruction should be performed in all cases because reducing the size of the TSE and providing firm support from below helps alter the downward CSF flow and prevents re-enlargement.

In our first case (case 48), the surgical strategy was informed by this theory. To reduce the size of the TSE and redirect CSF flow, the herniated sac was circumferentially dissected, and a portion of the mucosa was resected and trimmed. Although rigid reconstruction was initially planned, the TSE was extremely large and firmly adherent to the nasal mucosa, and detachment required considerable time, leaving the surgeon without the physical reserves to proceed with rigid reconstruction. Instead, the mucosa covering the TSE was meticulously coagulated and shrunk using bipolar cautery, and the TSE was suspended upward with multiple sutures as an alternative to rigid reconstruction. Autologous fat was then inserted into the cavity. The mucosa within the sphenoid sinus covering the TSE was sutured for watertight closure, circumferentially coagulated, and then suspended superiorly using a thread. This transnasal approach enabled clear visualization of the CSF dynamics within the cavity and to reliably alter CSF flow by reducing the size of the TSE and inserting fat, without disturbing the intra-TSE structures. Postoperatively, progression of the patient's visual field loss ceased and showed slight improvement. Notably, no recurrence of TSE was detected over a 14-year follow-up period.

Encouraged by the favorable outcome in our first case (case 48) and the preoperative cine MRI evidence of CSF inflow into the TSE in our second case (case 49), we aimed to refine and simplify the surgical technique. In this second case, the TSE was separated, elevated, and reduced in size. To prevent CSF leakage, it was covered with a sphenoid sinus mucosal flap,²⁹⁾ and rigid reconstruction of the sella turcica was performed using the patient's own septal bone to provide structural support.

Postoperative outcomes

Of the 49 patients who underwent surgical treatment, clinical outcomes were available for 44 cases. Of these, 36 (81.8%) showed symptom resolution or improvement. In our two cases, progression of symptoms ceased and visual fields improved postoperatively (Fig. 2g and h and Fig. 4h), with no complications or recurrence. We attribute these favorable outcomes to our surgical strategy―the endonasal approach―which avoided manipulation of the internal structures of the TSE, targeting only its external circumference.

The validity of our approach was further supported by preoperative and postoperative cine MRI findings in the second case: preoperative imaging demonstrated CSF flow into the TSE, which was no longer observed postoperatively (Fig. 3f and Fig. 4g). Additional techniques to prevent recurrence due to CSF pulsation included thread suspension in the first case (Fig. 2d) and rigid reconstruction of the sellar floor using bone in the second case (Fig. 4c and d), both of which proved successful. These favorable outcomes were largely attributable to the operating surgeon's experience in pituitary surgery.

In the first case, shrinkage of the TSE led to improved nasal airflow, enabling nasal breathing and restoration of the sense of smell (Fig. 2e and f), which significantly enhanced the patient's quality of life. Unfortunately, pituitary function did not recover in either case, underscoring the gland's vulnerability. Nevertheless, the importance of hormone replacement therapy is emphasized by the fact that the first patient achieved a spontaneous pregnancy five years after surgery.

In conclusion, TSE is an exceedingly rare skull base anomaly that presents significant diagnostic and surgical challenges. Early recognition, accurate neuroimaging, and individualized surgical planning are essential for achieving optimal outcomes. The endoscopic endonasal approach, as the first-line choice, has demonstrated safety, minimal invasiveness, and efficacy, yielding favorable clinical outcomes. Long-term follow-up is crucial for monitoring recurrence, visual function, and endocrine status. Further studies and larger case series are warranted to establish standardized treatment protocols for this complex condition.

Disclaimer

Author Takakazu Kawamata is one of the Editorial Board members of the Journal. This author was not involved in the peer-review or decision-making process for this paper.

Conflicts of Interest Disclosure

All authors have no conflict of interest.