Diagnostic Insights and Surgical Outcomes of Glomangiopericytoma: A Tertiary Center Case Series

Abstract

Background and Objectives

Glomangiopericytoma (GPC) is a rare, low-grade mesenchymal neoplasm that most commonly arises in the nasal cavity and paranasal sinuses. Its rarity, together with overlapping histopathological features shared with other spindle-cell tumors, makes diagnosis challenging, and available data regarding its clinical behavior and optimal management remain limited. This study aimed to present a retrospective case series of GPC from a tertiary referral center, with particular emphasis on clinical presentation, diagnostic evaluation, histopathological characteristics, surgical management, and outcomes.

Methods

Following institutional ethics approval, we conducted a retrospective review of patients treated for GPC between January 2010 and August 2025 at a tertiary care center. Collected data included demographic characteristics, clinical presentation, imaging findings, histopathological features with immunohistochemistry, surgical management, and follow-up outcomes.

Results

Eleven patients (six women and five men; mean age, 70.9 years) were included. The most common presenting symptoms were unilateral nasal obstruction, rhinorrhea, headache, and recurrent epistaxis. Tumors predominantly involved the nasal cavity—particularly the posterior septum, sphenoethmoidal recess, and middle turbinate—as well as the ethmoid sinus. Four cases demonstrated locoregional extension, and two required skull base reconstruction. Tumor diameter ranged from 0.8 to 4.0 cm. All patients underwent endoscopic endonasal resection. No recurrences were observed during follow-up, which ranged from 1 month to 15 years (mean, 3.54 years); however, these findings should be interpreted cautiously given the variability in follow-up duration. Immunohistochemistry consistently demonstrated nuclear β-catenin positivity and negative STAT6 expression.

Conclusion

GPC is a rare and distinct vascular neoplasm characterized by perivascular spindle-cell proliferation and nuclear β-catenin expression. Endoscopic resection was the primary treatment modality in our cohort, and long-term surveillance remains essential because of the potential for delayed recurrence. This case series provides a descriptive overview of the clinical features, diagnostic approaches, and management of GPC.

INTRODUCTION

Glomangiopericytoma (GPC) is an extremely rare mesenchymal neoplasm of borderline low malignant potential that primarily arises in the nasal cavity and paranasal sinuses. Although generally considered indolent, GPC can demonstrate locally aggressive behavior, including invasion into adjacent structures such as the sinus walls, orbits, and skull base [1–5]. It accounts for less than 0.5% of all sinonasal tumors and may occur across a wide age range; however, it most frequently presents in the seventh decade of life and shows a slight female predominance [2,5–7].

GPC was originally regarded as a variant of hemangiopericytoma. First described by Stout and Murray in 1942, hemangiopericytoma was defined as a vascular neoplasm characterized by a pericytic growth pattern surrounding thin-walled, branching vessels—commonly referred to as “staghorn-like” because of their distinctive morphology. Similar lesions arising in the nasal cavity were later termed “hemangiopericytoma-like tumors” by Compagno and Hyams in 1976, reflecting their relatively indolent clinical behavior and low metastatic potential. In 1998, Granter and colleagues proposed the term “glomangiopericytoma” to describe a distinct neoplasm exhibiting overlapping histopathological features of glomus tumors and hemangiopericytomas. Subsequently, in 2005, the World Health Organization (WHO) formally reclassified these tumors as GPC, recognizing their unique clinical behavior, histological architecture, and genetic profile.

In contrast to solitary fibrous tumors (SFTs), which encompass hemangiopericytoma as a cellular variant and are characterized by the NAB2–STAT6 gene fusion with corresponding STAT6 nuclear positivity, GPC demonstrates myoid differentiation, a generally favorable clinical prognosis, and nuclear β-catenin expression resulting from activating CTNNB1 mutations. These molecular and immunohistochemical differences support the classification of GPC as a distinct pathological entity [2,5,7–10].

In 2015, Lasota et al. [11] analyzed 13 cases of GPC and reported that nearly all tumors exhibited strong nuclear β-catenin expression associated with CTNNB1 mutations, suggesting a potential molecular driver for tumorigenesis. These findings were subsequently incorporated into the revised immunohistochemical criteria for GPC in the fourth edition of the WHO Classification of Head and Neck Tumours [12]. However, several later studies have reported variable immunophenotypic profiles, with inconsistent expression of Bcl-2 and CD34 and with smooth muscle actin (SMA) not uniformly positive [2,13]. These observations suggest that the immunohistochemical profile of GPC may be more heterogeneous than initially described in the WHO classification.

Despite these advances and increasing recognition of GPC as a distinct entity, comprehensive data remain limited regarding the most frequently affected subsites within the nasal cavity, potential etiological factors, and standardized immunohistochemical profiles and diagnostic criteria [11,12].

Furthermore, no formal clinical guidelines have been established for the management of GPC. In this study, we present a single-center retrospective case series, supplemented by a comprehensive review of the existing literature, with the aim of deepening the current understanding of the clinical presentation, diagnostic evaluation, and management strategies for GPC.

METHODS

A retrospective review was conducted of histologically confirmed cases of GPC managed at Asan Medical Center between January 2010 and August 2025. The study was approved by the Institutional Review Board of Asan Medical Center (Approval No. S2025-1960-0001), and the requirement for informed consent was waived because of the retrospective study design.

All consecutive patients with a histopathological diagnosis of GPC during the study period were included. Cases were identified through the institutional pathology database, and patients with incomplete medical records or uncertain diagnoses were excluded. Clinical and demographic data, including age, sex, presenting symptoms, symptom duration, prior sinonasal surgery, and medical comorbidities, were extracted from electronic medical records. Imaging studies, including contrast-enhanced computed tomography (CT) and/or magnetic resonance imaging (MRI), were reviewed to assess tumor location, extent, and radiological characteristics. Details regarding the surgical approach and extent of resection were also recorded. Postoperative follow-up data included endoscopic findings, radiological surveillance, tumor recurrence, and adjuvant treatment, when applicable.

Histopathological slides were reviewed by board-certified pathologists to confirm the diagnosis. Representative hematoxylin and eosin–stained sections were evaluated for characteristic morphological features, including cellular arrangement, vascular architecture, and stromal changes. Immunohistochemical staining was performed using standard automated techniques with antibodies against SMA, β-catenin, CD34, STAT6, and Ki-67.

Follow-up duration was calculated from the date of surgery to the most recent clinic visit or to the date of documented recurrence. Recurrence was defined as radiologically or histologically confirmed tumor reappearance following complete surgical excision.

Descriptive statistics were used to summarize the demographic and clinical characteristics of the study cohort. All statistical analyses were performed using SPSS software, version 19.0 (IBM Corp.).

RESULTS

A total of 11 patients diagnosed with GPC were included in the analysis. Patient ages ranged from 48 to 83 years (mean, 70.9 years), with a slight female predominance (6 females and 5 males) (Table 1). The most common presenting symptoms were unilateral nasal obstruction, rhinorrhea, headache, and recurrent epistaxis. Less frequent symptoms included hyposmia, facial pain, and snoring. In one patient, the tumor was incidentally identified on imaging performed for unrelated reasons (Fig. 1).

Table 1.

Demographic, clinical data, and prognosis

Case	Age (yr)	Sex	Chief complaint	Origin	Longest diameter on imaging (cm)	Locoregional extension	Follow-up (mo)
1	75	Male	An incidental finding	Middle turbinate	1.1	No	36
2	48	Female	Frontal headache, snoring	Anterior ethmoid sinus	3.5	Destruction of cribriform plate and lateral lamella	180
3	83	Male	Recurrent epistaxis, rhinorrhea	Posterior nasal septum	1.5	No	3
4	69	Male	Nasal obstruction	Posterior ethmoid sinus	4.0	No	48
5	79	Female	Nasal obstruction, facial pain, headache	Posterior nasal septum	2.8	Extension to the contralateral nasal cavity	48
6	71	Female	Recurrent epistaxis, rhinorrhea, hyposmia	Anterior ethmoid sinus	3.7	Erosion of cribriform plate	36
7	64	Female	Recurrent epistaxis, nasal obstruction, rhinorrhea, headache, and facial pain	Posterior ethmoid sinus	2.7	No	31
8	58	Male	Nasal obstruction	Posterior nasal septum	3.4	No	19
9	56	Female	Snoring, sleep apnea	Left buccal space, retroantral space, and masticator space	4.0	Extension into pterygopalatine fossa	60
10	73	Female	Rhinorrhea	Sphenoethmoidal recess	0.8	No	5
11	83	Male	Rhinorrhea, nasal obstruction, hyposmia, occipital headache	Sphenoethmoidal recess	2.0	No	1

Fig. 1.

Clinical presentations of patients with glomangiopericytoma.

The longest tumor diameter on imaging ranged from 0.8 to 4.0 cm (mean, 2.68 cm). Tumors most frequently involved the nasal cavity (6 of 11 patients, 54.5%), followed by the ethmoid sinuses (4 of 11 patients, 36.4%). The most commonly affected sinonasal subsite was the posterior nasal septum (3 of 11 patients, 27.3%), followed by the posterior ethmoid sinus, anterior ethmoid sinus, and sphenoethmoidal recess (each 2 of 11 patients, 18.2%). Less commonly involved subsites included the middle turbinate and the extranasal buccal space (each 1 of 11 patients, 9.1%). These findings indicate that GPC most often arises within the posterior nasal septum and ethmoid sinuses, while rare extranasal extension can occur. Locoregional extension was identified in four patients (36.4%), including anterior skull base erosion, pterygopalatine fossa involvement, and extension into the contralateral nasal cavity (Table 1).

All patients underwent endoscopic endonasal resection, with negative margins confirmed intraoperatively by frozen section. Skull base reconstruction was required in two patients (18.2%), and one patient (9.1%) underwent an endoscopic transpterygoid approach to facilitate tumor access. The duration of follow-up varied widely, ranging from 1 month to 15 years (mean, 3.54 years). No recurrences were observed during the follow-up period (Table 1).

Immunohistochemical staining was performed variably across cases (Table 2). β-catenin was evaluated in eight cases and demonstrated positivity in all tested specimens. SMA was assessed in all 11 cases and was positive in 10 of 11 (90.9%), including one case with focal positivity. S100 protein was tested in one case and was negative. CD34 was evaluated in five cases, with one positive and four negative results. STAT6 was tested in three cases and was negative in all. Desmin was assessed in two cases and was negative in both. Focal expression of BCL2, calponin, or CD99 was observed in isolated cases. Collectively, these findings are consistent with the characteristic immunoprofile of GPC, defined by diffuse β-catenin and SMA positivity with absence of S100 and STAT6 expression, which assists in distinguishing GPC from other sinonasal spindle-cell neoplasms. We also present detailed clinical, radiologic, and histopathological descriptions of three representative cases to illustrate the spectrum of GPC.

Table 2.

Immunohistochemical findings in glomangiopericytoma

Case	β-catenin	SMA	S100	CD34	STAT6	BCL2	Desmin	CD99	Calponin
1	NT	+	NT	−	NT	+	NT	+	NT
2	NT	−	NT	−	NT	NT	−	NT	NT
3	+	+	NT	NT	NT	NT	NT	NT	NT
4	+	+	NT	NT	NT	NT	NT	NT	NT
5	+	+	NT	NT	NT	NT	NT	NT	NT
6	+	+	NT	NT	NT	NT	NT	NT	+
7	+	+	NT	NT	NT	NT	NT	NT	NT
8	+	F+	−	+	−	NT	NT	NT	NT
9	NT	+	NT	−	−	NT	−	NT	NT
10	+	+	NT	−	−	NT	NT	NT	NT
11	+	+	NT	NT	NT	NT	NT	NT	NT

SMA, smooth muscle actin; NT, not tested; F+, focal positive; +, positive; −, negative.

Case 1

A 79-year-old woman with a history of hypertension, diabetes mellitus, prior myocardial infarction, and cerebrovascular accident presented with left-sided intermittent nasal obstruction of approximately two years’ duration, accompanied by facial pain, frontal and temporal headaches, mucopurulent left-sided rhinorrhea, sneezing, nasal and ocular itching, hyposmia, and intermittent snoring. Nasal examination revealed a mass arising from the left posterior nasal septum. Contrast-enhanced CT of the paranasal sinuses demonstrated a 2.8 cm mass centered on the left nasal septum, extending into the left choana and crossing into the right nasal cavity (Fig. 2). Magnetic resonance imaging of the head and neck was subsequently performed for further evaluation (Fig. 3).

Fig. 2.

Contrast-enhanced coronal and axial computed tomography images of the sinuses show a 2.8 cm mass (*) centered on the left nasal septum, extending into the left nasal choana and crossing into the right nasal cavity.

Fig. 3.

An approximately 2.8 cm mass involves both nasal cavities, extending posteriorly to the left choana and contralateral nasal cavity. The mass causes central thinning of the nasal septum and demonstrates strong enhancement with early wash-in and delayed washout. No definite diffusion restriction is observed.

The patient underwent left endoscopic endonasal resection following appropriate preoperative assessment. Histopathological examination confirmed GPC, with immunohistochemical positivity for SMA and nuclear β-catenin. The patient was followed for four years postoperatively and remained disease-free, with no clinical evidence of recurrence.

Case 2

A 71-year-old woman with a history of hypertension presented with epistaxis of 10 days’ duration, accompanied by bilateral watery rhinorrhea and sneezing for three weeks. She reported longstanding hyposmia for approximately 30 years but denied trauma, nasal obstruction, facial pain, headache, or snoring. Endoscopic examination revealed a mass arising from the right middle meatus.

CT demonstrated a homogeneously enhancing mass measuring approximately 3.7 cm, involving the right ethmoid sinuses, with erosive changes affecting the nasal septum and right cribriform plate (Fig. 4). Differential diagnoses included olfactory neuroblastoma and other sinonasal malignancies. Positron emission tomography/computed tomography revealed a mildly hypermetabolic sinonasal tumor without evidence of regional or distant metastasis.

Fig. 4.

Computed tomography and magnetic resonance images demonstrate a homogeneously enhancing mass measuring approximately 3.7 cm, involving the right ethmoidal sinuses, with erosive changes are noted in the nasal septum and the right cribriform plate.

The patient underwent right endoscopic endonasal resection with skull base reconstruction. Histopathological examination confirmed GPC. Immunohistochemistry demonstrated positivity for nuclear β-catenin, SMA (weak), calponin (focal), and TLE-1, and negativity for CD34, cytokeratin, S100, STAT6, and SOX-10. The Ki-67 labeling index was low at 2.6%, consistent with indolent tumor behavior. The patient remained disease-free during three years of postoperative follow-up.

Case 3

A 56-year-old woman presented with snoring and sleep apnea. She denied nasal obstruction, rhinorrhea, facial pain, headache, postnasal drip, trauma, sneezing, itching, cough, or sputum production.

CT revealed a soft tissue mass involving the left buccal space, extending into the retroantral and masticator spaces, with insinuative growth into the pterygopalatine fossa and inferior orbital fissure, measuring up to 4 cm in greatest dimension (Fig. 5). The mass demonstrated heterogeneous intermediate T2 signal intensity, well-defined contrast enhancement, and linear calcification on CT. No significant diffusion restriction or regional lymphadenopathy was identified. Differential diagnoses included SFT, fibromatosis, and, less likely, hemangioma.

Fig. 5.

Computed tomography findings demonstrating a soft tissue mass (*) involving the left buccal space, with extension into the retroantral and masticator spaces. The lesion exhibits insinuative growth into the pterygopalatine fossa and inferior orbital fissure, measuring up to 4 cm in greatest dimension.

The patient underwent preoperative embolization followed by tumor excision via an endoscopic transmaxillary and transpterygoid approach with navigation guidance, including endonasal medial maxillectomy and resection of the posterior and lateral walls of the maxillary sinus.

Histopathological examination revealed a low-grade spindle cell lesion favoring GPC, with low mitotic activity, absence of necrosis, and indeterminate resection margins. There was no involvement of the inferior orbital fissure or foramen rotundum. Immunohistochemistry demonstrated positivity for SMA and negativity for CD34, desmin, and STAT6, with a Ki-67 index of less than 5%, supporting the diagnosis. The patient remained disease-free during five years of postoperative follow-up.

DISCUSSION

Our findings are consistent with previously published reports describing the demographic and clinical characteristics of GPC, including a mean patient age in the seventh decade of life and a slight female predominance. The etiology of GPC remains uncertain. Although factors such as hypertension, trauma, and prolonged corticosteroid use have been proposed as potential contributors, these associations have not been systematically evaluated in clinical studies or supported by statistical analysis [14–16]. Notably, our study is the first to systematically delineate the most frequently involved nasal subsites in GPC. Consistent with prior reports, the nasal cavity was most commonly affected, followed by the ethmoid and sphenoid sinuses [1,2,5,6]. Within the nasal cavity, the posterior nasal septum, sphenoethmoidal recess, and middle turbinate were the predominant subsites in our cohort, reflecting the tumor’s apparent predilection for regions with a rich vascular supply.

Clinical presentation and imaging findings

Patients most commonly presented with unilateral nasal obstruction, rhinorrhea, headache, and recurrent epistaxis, whereas hyposmia and snoring were reported less frequently [4,6,13,17,18]. On endoscopic examination, tumors typically appeared as vascular, friable, erythematous polypoid masses. Imaging played a critical role in diagnosis and surgical planning: CT generally demonstrated well-circumscribed, contrast-enhancing lesions with occasional bony remodeling, while MRI typically revealed T1 isointensity, T2 hyperintensity, and avid post-contrast enhancement [1,3,4,17,19,20].

Histopathology and immunohistochemistry

GPC is characterized by submucosal proliferation of uniform spindle to oval cells arranged around thin-walled, branching (“staghorn”) vessels [1,4]. This architectural pattern assists in distinguishing GPC from epithelial tumors such as squamous cell carcinoma or inverted papilloma [1]. Immunohistochemically, GPC commonly expresses α-SMA, vimentin, and nuclear β-catenin, whereas CD34, Bcl-2, S100, cytokeratins, and STAT6 are typically negative, although focal CD34 or Bcl-2 expression may be observed [2,4,8,18,21]. In a systematic review of 337 cases, Park et al. [2] reported α-SMA positivity in 86%, CD34 negativity in 76%, and Bcl-2 negativity in 90% of cases, with nuclear β-catenin expression identified in all tumors tested.

At the molecular level, activating mutations in CTNNB1 drive aberrant nuclear accumulation of β-catenin, which represents a defining feature of GPC [2,3,4,18]. Lasota et al. [11] confirmed uniform nuclear β-catenin expression in all 13 cases examined, underscoring the role of Wnt/β-catenin pathway dysregulation in tumor pathogenesis, although their study did not include clinical or surgical outcome data.

Differential diagnosis

GPC must be distinguished from vascular and spindle cell neoplasms that exhibit overlapping histological features. Hemangiomas lack perivascular spindle cell proliferation and demonstrate CD31 and CD34 positivity limited to endothelial cells. Juvenile nasopharyngeal angiofibroma occurs predominantly in adolescent males and lacks a uniform perivascular cellular arrangement. Angiosarcoma is characterized by atypical endothelial cells forming irregular vascular channels with diffuse endothelial marker positivity.

Among spindle cell tumors, SFT most closely resembles GPC because of its prominent vasculature, but it typically shows a “patternless” architecture, alternating hypercellular and hypocellular areas, ropy collagen, and CD34 and STAT6 positivity. Schwannomas and neurofibromas express S-100 and SOX10, with schwannomas additionally demonstrating characteristic Antoni A and Antoni B areas. Inflammatory myofibroblastic tumor shows a mixed inflammatory infiltrate and ALK positivity. Sarcomatoid squamous cell carcinoma, sinonasal undifferentiated carcinoma, and spindle cell melanoma may also mimic GPC morphologically, but they express cytokeratin or melanocytic markers, in contrast to GPC [4,8,18,21].

A concise immunohistochemical panel—including β-catenin, SMA, CD34, STAT6, S-100, SOX10, cytokeratin, and CD31—can facilitate accurate diagnosis, particularly when only limited biopsy material is available [4,8,18,21].

Management and prognosis

All tumors in our series were managed successfully by endoscopic endonasal resection, supporting its role as a minimally invasive and effective surgical approach. Preoperative embolization may be considered for large or highly vascular lesions. No external approaches were required in our cohort; such interventions should be reserved for recurrent disease or tumors with extensive skull base or cavernous sinus involvement [4,5,17,19,21].

GPC responds poorly to radiotherapy and chemotherapy, and complete surgical excision remains the treatment of choice. Surgical re-excision is recommended for recurrent cases. Overall prognosis is favorable, with a reported 5-year survival rate of approximately 88% and recurrence rates ranging from 10% to 17%, most commonly associated with positive surgical margins. Distant metastasis is rare, occurring in fewer than 5% of cases [1–3,19]. Park et al. [2] identified predictors of improved survival, including younger age, right-sided tumor location, negative margins, and the absence of recurrence or metastasis. Favorable immunoprofiles included actin positivity and CD34 and Bcl-2 negativity. CD34-positive GPCs may mimic SFTs and exhibit more aggressive features; Arnous et al. [13] reported a skull base case with CD34 positivity but absent STAT6 expression, supporting a diagnosis of GPC.

Given the potential for late recurrence, long-term follow-up is essential. Our surveillance protocol includes endoscopic examinations every 3 to 6 months during the first two postoperative years, followed by annual visits thereafter. Although all patients in our study remained free of recurrence, the duration of follow-up varied widely, ranging from 1 month to 15 years. Because GPC may recur years after initial treatment, these findings should be interpreted as preliminary and do not confirm curative outcomes. Longer and more uniform follow-up is required to establish durable long-term disease control.

Study contribution and limitations

In 2023, Schauwecker et al. [19] reported six cases of GPC, representing the largest purely single-center clinical series at that time. Our cohort of 11 patients therefore constitutes a larger single-institution dataset focused exclusively on this rare tumor, providing integrated clinical, radiologic, surgical, and histopathological correlations.

This study is limited by its retrospective, single-center design, and the relatively small sample size restricts the generalizability of the findings. Nevertheless, it provides valuable evidence supporting endoscopic resection as a safe and potentially curative approach for GPC. Future multicenter, prospective studies incorporating molecular and immunohistochemical profiling are warranted to validate prognostic factors and guide evidence-based management strategies.

Conclusion

GPC is a rare, low-grade neoplasm characterized by perivascular growth and nuclear β-catenin expression. Endoscopic surgical excision was the treatment of choice in our cohort, with preoperative embolization reserved for select large or hypervascular tumors. With appropriate surgical management, prognosis is generally favorable; however, the risk of delayed recurrence underscores the importance of long-term surveillance. This single-center retrospective series provides a descriptive overview of the clinical features, diagnostic approaches, and management of GPC. These findings add to the existing literature and highlight areas in which larger, collaborative studies are needed.