Hemangiopericytoma was first described by Stout and Murray as a less organoid form of glomus tumour arising from pericytes.(Hemangiopericytoma: a vascular tumour featuring Zimmermann's pericytes. Ann Surg 1942: 116: 26-33).

Enzinger and Smith (Hemangiopericytoma. An analysis of 106 cases.Hum Pathol. 1976 Jan;7(1):61-82.) divided this tumour into two groups:
  I. Adult   II. Infantile or congenital hemangiopericytoma.

The concept of 'Hemangiopericytoma' has been questioned my many authors due to absence of reproducible  diagnostic criteria.

(Hemangiopericytoma: a dying breed? Reappraisal of an ‘entity’ and its variants: a hypothesis. Curr Diagn Pathol 1994;1:19–23.)
 

Many soft tissue tumours focally display 'hemangiopericytoma- like' pattern.

Differential diagnosis: 

Solitary fibrous tumour ; Synovial sarcoma ; Infantile myofibromatosis ;  Infantile fibrosarcoma ; Malignant fibrous histiocytomas  ;  Malignant peripheral nerve sheath tumors ;

Low-grade endometrial stromal sarcoma. (Mod Pathol. 2005 Jan;18(1):40-7) ; 

Juxtaglomerular  tumour ;  (Am J Clin Pathol 2001 Dec;116(6):854-63)

Mesenchymal chondrosarcoma ;  Phosphaturic mesenchymal tumour;  Osteosarcoma;   Malignant mesotheliomas ; Thymomas ; Sarcomatoid carcinomas ; Melanoma

Occurs in  elderly patients  and is usually located in deep soft tissue, lower extremities, pelvis and retroperitoneum.

Gross:    Solitary well circumscribed solid tumour with a smooth surface. Sectioning reveals greyish white to reddish brown areas . Areas of hemorrhage, necrosis and cystic degeneration are often present.

Microscopic features:  The tumour is characterized by tightly  packed cellular areas surrounding thin walled branching blood vessels. The tumour cells are small, ovoid to spindle shaped with ill-defined cell boundaries.
The collapsed  blood vessels, lined by flat endothelial cells, are arranged in a 'stag-horn' pattern .
The spindle cells are each surrounded by a reticulin  sheath and are separated from the endothelial cells by a basement membrane.
Silver stain demonstrates extravascular location of the tumour cells and individual cells display pericellular reticulin pattern.

Immunohistochemistry:   Actin and other myoid markers are negative. Vimentin and CD34 shows nonspecific positivity.

The features indicating  poor prognosis include increased cellularity, necrosis , hemorrhage, more than 4 mitotic figures per 10 high power fields.

                       Pathology Quiz Case16:

Diagnosis:

       Path Case 16:Case history and images:

Sinonasal hemangiopericytoma  is a rare upper aerodigestive tract tumour of unknown histogenesis.
The most frequent site of occurence is the nasal cavity and paranasal sinuses.

Microscopic features:   Image Link1 ; Image Link2 ; Image Link3 ; Image Link4 .

The tumour is composed of uniform, spindle shaped cells with round to oval  nuclei arranged in short fascicles.  The vascular component includes capillary size to large sinusoidal spaces. Some vessels have  a staghorn like appearance.  Perivascular hyalinization is often present.

Subtypes of sinonasal hemangiopericytoma:

  I) Soft tissue type hemangiopericytoma:    Aggressive tumour;  Locally destructive and may metastasize to regional lymphnode and lung  ; Do not show myoid differentiation ;  Smooth muscle actin and other myoid markers are negative; Very recently intimate relationships between hemangiopericytoma and solitary fibrous tumor have been reported. It is important to differentiate these tumours, because most solitary fibrous tumors of the soft tissue are benign.

 II) True hemangiopericytoma:    Benign behaviour ; Do not metastasize ;  Tumour has a myogenic appearance and shows convincing pericytic differentiation ; Smooth muscle actin is positive ; Some of these tumours recur locally. 

 III) Sinonasal glomus tumours:   Histology ranges from a typical glomus tumor composed of compact epithelioid cells to tumours indistinguishable from perivascular myoma. Glomus and glomus-like tumours and true hemangiopericytomas are likely to belong to one cellular spectrum.

Abstracts:

-Intranasal glomus tumor.Arch Otolaryngol. 1984;110(11):755-6.

-Aggressive glomus tumor of the nasal region. Report of a case with multiple local recurrences.Arch Pathol Lab Med. 1993;117(6):649-52.

-Nasal glomus tumors: report of two cases with emphasis on immunohistochemical features and differential diagnosis.Hum Pathol. 1999 ;30(10):1259-61. 

Differential diagnosis of sinonasal hemangiopericytoma:   Sinonasal true hemangiopericytoma should be differentiated from soft tissue- type hemangiopericytoma because of its far better prognosis.

Solitary fibrous tumour(CD34 is diffusely positive); Cellular Angiofibroma ; Fibrohistiocytic tumour ; Lobular capillary hemangioma ; Glomus tumour ;

Abstracts:

-Sinonasal hemangiopericytoma-like tumor with true pericytic myoid differentiation: a clinicopathologic and immunohistochemical study of five cases.Head Neck. 2005;27(2):124-9.

-Sinonasal type hemangiopericytoma: a clinicopathologic and immunophenotypic analysis of 104 showing perivascular  myoid differentiation. Am J Surg. Pathol. 2003(6); 737- 49

-Intranasal pericytic tumors (glomus tumor and sinonasal hemangiopericytoma-like tumor): report of two cases with review of the literature.Pathol Int. 2003 ;53(5):303-8.

-Sinonasal hemangiopericytoma like tumour: a sinonasal glomus tumour or a hemangiopericytoma? Histopathology.  2002; 40(6) 510- 7

Usually present at  birth or noted soon after. This tumour has a benign course.

Site:   Mostly solitary lesion, located on the head and neck area, extremities or the trunk.

Microscopic features:  The multilobulated tumour displays polymorphic population of cells consisting of spindle cells with myofibroblastic features and a more primitive round cells (both are smooth muscle actin positive).

There are distinct intravascular and perivascular satellite nodules outside the main tumour mass.  There is evidence of intravascular endothelial cell proliferation. 

Mitotic figures are noted together with focal necrosis and vascular invasion (this is not related to bad prognosis).

It has been suggested that infantile myofibromatosis and infantile hemangiopericytoma represent different stages of maturation  of the same lesion.

Abstracts:

Infantile hemangiopericytoma versus infantile myofibromatosis. Study of a series suggesting a continuous spectrum of infantile myofibroblastic lesions.
Am J Surg Pathol. 1994;18(9):922-30.

Hemangiopericytoma in pediatric ages: a report from the Italian and German Soft Tissue Sarcoma Cooperative Group.Cancer. 2001;92(10):2692-8.

Hemangiopericytoma in children and infants. Cancer 2000 ;88(1):198-204

Myopericytoma include a range of lesions displaying features ranging from  myofibromatosis to those resembling glomus tumour  with hemangiopericytoma-like blood vessels.

Microscopic features:   The tumour exhibits biphasic pattern characterized by primitive spindle cell with hemangiopericytoma-like vascular pattern and fascicles of spindle cells with eosinophilic cytoplasm, resembling smooth muscle.

Glomangiopericytoma is characterized by branching blood vessels lined by endothelial cells surrounded by epithelioid cells (glomoid appearance).

Abstracts:

-Malignant myopericytoma: expanding the spectrum of tumours with myopericytic differentiation. Histopathology. 2002;41(5):450-60.

-Intravascular myopericytoma.J Cutan Pathol 2002;29(9):557-61

Lipomatous hemangiopericytoma, a rare soft tissue tumour with unpredictable biologic behavior,was reported in 1995 by Nielsen et al.

The tumour shows clinical, pathologic, immunohistochemical, and ultrastructural features of a solitary fibrous tumour and probably represent, in most cases, a fat-containing variant of solitary fibrous tumour.

Age: Usually occurs in middle-aged patients. (mean age 54 years)

Site:  The locations included the sinonasal area, orbit , neck, mediastinum, epicardium, soft tissue of the shoulder and the retroperitoneum, right iliac fossa , upper and lower extremity.

Gross feature: The tumour usually ranges in size from 4 to 10 cm in greatest diameter. Macroscopically, it is a solid mass with a tan to yellow cut surface.

Microscopic features:

The tumour has a relatively sharp border and is composed of a variable admixture of benign lipomatous and hemangiopericytomatous components.

The hemangiopericytomatous component included oval to round cells surrounding a sinusoidal and staghorn vasculature often with perivascular hyalinization.

Mature fat varied in amount but usually occupied approximately one quarter to three quarters of the area of tumour. 

The mitotic activity usually ranged from 1 to 3 mitoses per 10 high-power fields (HPF).

In one case, many multivacuolated adipocytes of variable size with characteristic nuclear scalloping (lipoblast-like cells) are present.

Immunohistochemistry:  The tumour stained with antibodies to vimentin and not to alpha-smooth-muscle actin, muscle-specific actin, desmin, S-100 protein, glial fibrillary acidic protein, epithelial membrane antigen  or keratin.

Differential diagnosis :    

Spindle cell neoplasms mixed with adipose tissue include-  Extrathoracic solitary fibrous tumours ;  Cellular angiofibroma ; Spindle cell lipoma ; Dendritic fibromyxolipoma.

Angiolipoma ;  Liposarcoma ;  Tumours showing smooth muscle and adipocytic differentiation ;  Hemangiopericytoma infiltrating fat.