HEMANGIOPERICYTOMA

DR SUHAS K R

3-5% of all soft tissue sarcomas

1% of all vascular tumors.

The head and neck incidence is 15-30%

Usually seen in the orbit, nasal cavity, oral cavity, jaw, parotid

gland, parapharyngeal space, masticator space and jugular

foramen

5th to 6th decade of life

Introduction

History

The first reported case of HPC in head and neck was of nasal

HPC, another was in the tongue base in 1949 by Stout and

Murray

Since then, only approximately 300 cases of HPCs have been

mentioned in the literature

Head and neck

Vascular tumors arising from Zimmerman’s pericytes

These cells are arranged alongside capillary vessels and have

smooth muscle characteristics

Responsible for vessel caliber regulation owing to their contractile

capability, modulating both flux and permeability

Origin

No etiological factors identified

a past history of trauma,

prolonged steroid use and

hypertension

Etiology

Slow-growing painless mass

No outward sign of the vascular nature of the tumour is usually

evident

Pain occurs in locally invasive large lesions or when it is

confined in unyielding spaces such as the paranasal sinuses

However, pain is characteristic of bone or pulmonary

metastases.

Clinical features

juvenile hemangioma,

glomus tumor, angiosarcoma,

leiomyoma, leiomyosarcoma, schwannoma, mesothelioma,

liposarcoma, benign and malignant histiocytoma,

synovial sarcoma, chondrosarcoma, neuroblastoma

Differential diagnosis of

hemangiopericytoma

FNAC – Cant confirm the diagnosis

INCISIONAL BIOPSY - when there is suspicion of malignancy

Risk of bleeding

Avoided in para spinal, closed spaces.

Investigation

Radiology

The tumour usually appears as a

solid mass, hypodense on CT and

isointense on T1-weighted images

on MRI.

On T2- weighted images, the

tumour shows equal or lower

signal intensity

Hypervascularity, cystic low

attenuation zones, septations and

speckled calcifications

Non-HPC neoplasms that occasionally display HPC-like features (e.g.

synovial sarcoma)

True HPCs - clear evidence of myoid/pericytic differentiation -

glomangiopericytoma/myopericytoma, infantile myofibromatosis, and

a subset of sinonasal HPCs.

Solitary fibrous tumor (SFT) lesional group, which includes fibrous-

to-cellular SFTs, and related lesions - giant cell angiofibromas and

lipomatous HPCs

HPC like neoplasms

HPC is a well-circumscribed, brown, spongiform lesion,

surrounded by a pseudo-capsule

Small satellite nodules separate from the main tumor mass

They can be lobulated or nodular, firmly attached to muscle or

fascia, and soft, firm or friable

Pathology

Small closely packed cells with ill defined cytoplasm and darkly

stained nuclei

Slit like or sinusoidal vascular spaces are interspersed between cells

Vimentin is the only marker expressed consistently

Pathology

Factors to differentiate benign from malignant

> four mitosis per field,

high cellularity,

pleomorphic tumour cells and

foci of haemorrhage and necrosis

size greater than 6.5 cm

Prognostic factors

HPE

Metastatic disease - in up to 50% of patients with the haematogenous

route.

It mostly metastasizes to lungs, bones and liver whereas lymph node

involvement is rare.

In head and neck - 40% recur locally and 10% have distant metastases

Biological behaviour of these neoplasms is rather peculiar, as benign-

looking, non-mitotic HPCs have been reported to metastasize

Tumor behaviour

The most common site of origin - palate, followed by the

mandible and the lower lip

Most of the oral hemangiopericytomas - invasive

Local recurrence or distant mets - 25 %

Oral cavity

Reported cases

Surgery - wide local excision

Angiography and pre-operative embolization may be

performed in large tumours with significant vascularity, in order

to decrease the size and vascularity of the tumour

Management

In general, haemangiopericytomas are considered to be radioresistant

and radiation therapy is not suggested as the primary treatment.

Reserved only for inoperable metastases or treatment of post-operative

surgical fields in case of close or positive margins

Someya et al 2001 - post op RT showed significantly improved local

control - 4 cases only

Adjuvant therapy

Infantile type has high response to chemo (Del Rosario and Saleh

1997)

Vincristine, cyclophosphamide, doxorubicin, methotrexate have all

been tried with limited success

CT in inoperable and metastatic patients

No role in R0 resections

Adjuvant chemo

Median age at diagnosis 13.5 years or less than one year

Better clinical behavior than the adult type

Chemoresponsiveness and spontaneous regression have been reported

in children younger than 1 year

Aggressive multimodality therapy

Childhood hemangiopericytoma

Usually worse in adult type

Enzinger and smith (1976 )reported 10 yr survival rate of 70 %

Espat et al 2002 - 93 % and 86 % two and five year survival rate

Even though there is high local recurrence and distant metastasis rate

HPC has low disease associated mortality

Prognosis

Relatively uncommon vascular tumours more so in head and neck

HPC is "defined" - by reactivity for vimentin, with or without CD34

and CD57 and lacks other immunodeterminants of epithelial, neural,

and myogenous differentiation.

Of all the vascular tumors the diagnosis of hemangiopericytoma is one

of the most controversial

Take home message

Surgical excision still remains the treatment of choice.

Role of adjuvant therapy is largely undefined

Clinical behaviour is difficult to predict

Patients need to be followed up closely for an extended period

Take home message

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