Glomangiopericytomas (GPC), also known as sinonasal-type haemangiopericytomas, are rare vascular tumours that typically arise in the nasal cavity and paranasal sinuses characterised by a perivascular myoid pattern 1.
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Terminology
Glomangiopericytomas (GPCs) are often referred to as sinonasal haemangiopericytomas. However, they are distinct from conventional haemangiopericytomas in their location, biological behaviour, and histological features 2.
Epidemiology
Glomangiopericytomas are rare, accounting for less than 0.5% of sinonasal tumours. They primarily affect older adults and have a slight female predominance 1.
Clinical presentation
Patients typically present with symptoms such as nasal obstruction, epistaxis (nosebleeds), and facial pain. Less commonly, they may experience anosmia, headaches, and proptosis if the tumour extends to adjacent structures 3.
Pathology
Glomangiopericytomas are characterised by a proliferation of spindle-shaped cells around blood vessels.
Location
Glomangiopericytomas primarily occur in the nasal cavity and paranasal sinuses. Rarely, they can be found in other locations such as the spinal cord or the pterygomandibular space 4,5.
Macroscopic appearance
Macroscopically, glomangiopericytomas appear as reddish, polypoidal masses. They are often friable and prone to bleeding upon manipulation 6.
Microscopic appearance
Microscopically, glomangiopericytomas consist of closely packed spindle cells arranged around a distinctive vascular network. The cells are uniform, with bland nuclei, and are surrounded by thin-walled, branching vessels, often described as having a "staghorn" appearance 3.
Immunophenotype
Immunohistochemistry is positive for α-smooth muscle actin, indicating myoid differentiation 1.
Radiographic features
Plain radiograph
They can show an unspecific soft tissue mass in the nasal cavity.
CT
CT is useful for evaluating the extent of the tumour and any potential bone involvement. Glomangiopericytomas typically appear as well-defined masses with uniform enhancement after contrast administration 1.
MRI
Provides superior soft tissue contrast and is useful for defining the tumour's relationship with adjacent structures 5.
Signal characteristics
T1: isointense to muscle
T2: heterogeneous high signal intensity
T1 C+ (Gd): vivid enhancement
Treatment and prognosis
The primary treatment for glomangiopericytomas consists of complete surgical resection. Endoscopic surgery is preferred due to its minimally invasive nature and effectiveness in complete tumour removal. The prognosis is generally good, with a low rate of malignancy and high survival rates if the tumour is fully excised. However, recurrence rates can be as high as 30%, necessitating long-term follow-up 7.
Differential diagnosis
General imaging differential considerations include 2,8:
solitary fibrous tumour: the heterogeneity and presence of cystic or necrotic areas can help distinguish SFTs from glomangiopericytomas, which tend to have more uniform enhancement
leiomyoma: the homogenous low signal on T2-weighted images can help differentiate leiomyomas from glomangiopericytomas, which generally show a more heterogeneous signal
angiofibroma: the presence of flow voids and intense enhancement on MRI can help distinguish angiofibromas from glomangiopericytomas, which typically do not exhibit flow voids
lobular capillary haemangioma: the small size and superficial location, combined with intense homogeneous enhancement, can help differentiate these from glomangiopericytomas, which are typically larger and deeper
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schwannoma: the presence of cystic areas and the "target sign" (central low signal with peripheral high signal on T2-weighted images) can help differentiate schwannomas from glomangiopericytomas