Sinonasal hemangiopericytomas: clinicopathologic and imaging findings.

Abstract

Hemangiopericytomas are rare soft-tissue neoplastic lesions that can arise in any part of the body. They are mesenchymal tumors that account for 3 to 5% of all soft-tissue sarcomas and 1% of all vascular tumors. They originate in extravascular cells (pericytes). Some 15 to 30% of all hemangiopericytomas occur in the head and neck; of these, approximately 5% occur in the sinonasal area. We describe our brief retrospective review of 7 histologically proven cases of sinonasal hemangiopericytoma, and we discuss the imaging characteristics and clinical and pathologic findings in these patients.

Introduction

Hemangiopericytomas are unusual vascular tumors that were first described by Stout and Murray in 1942. (1) These tumors originate in extravascular cells called pericytes, which presumably are modified contractile smooth-muscle cells found on the external surface of capillaries and post-capillary venules. (2,3) Hemangiopericytomas represent 3 to 5% of all soft-tissue sarcomas (4) and 1% of all vascular tumors. (5) They can arise in any location where capillaries are found, primarily in the lower extremities and the retroperitoneum. (3,6-8)

Approximately 15 to 30% of all hemangiopericytomas occur in the head and neck; of these, approximately 5% arise from the sinonasal cavity. (5,7-10) Sinonasal hemangiopericytomas are believed to behave less aggressively than do hemangiopericytomas that occur in other parts of the body. The 5-year survival rate for patients with sinonasal hemangiopericytoma is approximately 88%. (8,9,11)

In this article, we describe 7 cases of sinonasal hemangiopericytoma, and we discuss the imaging characteristics and clinical and pathologic findings.

Case reports

We identified 7 cases of histologically proven sinonasal hemangiopericytoma that occurred over 12 years at tour different institutions (Loyola University Hospital in Maywood, Ill.; Mac Neal Memorial Hospital in Berwyn, Ill.; the Louisiana State University Health Sciences Center in New Orleans; and the Fundacion Santa Fe de Bogota in Bogota, Colombia). We retrospectively reviewed the results of each patient's clinical, pathologic, and imaging examinations.

The 7 patients included 4 men and 3 women aged 23 to 66 years (mean: 51). All were evaluated clinically and imaged by computed tomography (CT); 3 patients also underwent magnetic resonance imaging (MRI). Four patients (patients 2, 3, 6, and 7) had involvement of the nasal cavity; 2 of them (patients 6 and 7) exhibited nasopharyngeal extension. Three patients (patients 1, 3, and 5) had ethmoid sinus involvement. One patient (patient 4) exhibited sphenoid sinus involvement with extension into the sellar area, cavernous sinuses, and optic chiasm. Two patients (patients 3 and 6) experienced a recurrence.

Patient 1. A 60-year-old man presented with a 2-year history of intermittent epistaxis. CT revealed a well-marginated soft-tissue mass in the superior portion of the right ethmoid sinus (figure 1). The tumor extended into the right cribriform plate. The patient underwent endoscopic surgery with complete removal of the hemangiopericytoma from the right ethmoid area. He developed a cerebrospinal fluid leak, which was repaired intraoperatively. At 22 months postoperatively, the patient was asymptomatic.

[FIGURE 1 OMITTED]

Patient 2. A 35-year-old woman complained of intermittent nasal obstruction and epistaxis on the left. MRI detected a soft-tissue mass in the nasal cavity on the left (figure 2). She was treated with a complete surgical resection of the mass. At the 12-month follow-up, she was asymptomatic and showed no sign of recurrence.

[FIGURE 2 OMITTED]

Patient 3. A 66-year-old man complained of nasal obstruction, pain in the nasal and malar areas, and epistaxis. He had a history of a nasopharyngeal angiofibroma that had been resected 16 years earlier. CT identified a large nasal soft-tissue mass that proved to be a sinonasal hemangiopericytoma. Following preoperative embolization, the mass was partially excised.

Follow-up CT and MRI (figure 3) 2 years later revealed the recurrence of a large soft-tissue mass in the nasal cavity. The mass had destroyed the turbinates and nasal septum and extended superiorly into both ethmoid sinuses, laterally into both maxillary sinuses, and inferiorly into the oral cavity. The recurrent mass was partially resected and treated with embolization and radiation therapy.

[FIGURE 3 OMITTED]

Patient 4. A 23-year-old woman reported a 6-month history of persistent and generalized headaches and occasional episodes of a spontaneous decrease in visual acuity in the right eye. In light of the progression of her symptoms, CT and MRI (figure 4) were performed. Imaging revealed the presence of a sphenoid mass that had extended into the sella, cavernous sinuses, and optic chiasm. The lesion was partially resected and treated with radiation. The patient continued to experience persistent neurologic deficits, but she exhibited no obvious evidence of recurrence at the 8-month follow-up.

[FIGURE 4 OMITTED]

Patient 5. A 64-year-old man sought evaluation for a history of chronic intermittent epistaxis and nasal obstruction. CT identified a soft-tissue mass that extended into the left ethmoid sinus. Complete resection of the mass was performed endoscopically. At 3 years postoperatively, he exhibited no evidence of recurrence.

Patient 6. A 48-year-old woman presented with a left nasopharyngeal mass with involvement of cranial nerves III, IV, and V. On CT, a mass was seen extending into the nasal cavity and left parasellar area. The lesion was surgically resected but, 8 years later, the patient experienced a recurrence of the mass and symptoms.

Patient 7. A 58-year-old man complained of nasal obstruction. CT identified a soft-tissue mass in the posterior nasal cavity that extended into the nasopharynx. The mass was surgically resected. After 4 years of follow-up, no sign of recurrence was evident.

Discussion

Sinonasal hemangiopericytoma usually affects middle-aged patients; its gender distribution is generally equal. (3,6-8,10) Although its etiology remains unknown, it has been tentatively associated with trauma, long-term steroid use, pregnancy, and hypertension. (7-10) It occurs in the nasal cavity approximately twice as often as it does in the paranasal sinuses. When it does involve the sinuses, it occurs in the ethmoid and sphenoid sinuses four times more often than it does in the maxillary sinuses. (7,8)

Endoscopically, hemangiopericytomas in the nasal cavity are soft and tan-colored. (8,9) These lesions typically enlarge slowly over a period of months or years, and they often cause nasal and sinus obstruction. Symptoms such as spontaneous or induced bleeding and impaired nasal breathing can begin to manifest long before diagnosis. (5,7,8) When these lesions invade the orbits and intracranial structures, ophthalmologic findings--including proptosis and visual loss secondary to cranial nerve involvement--may be observed. (5,12)

The propensity of sinonasal hemangiopericytomas to expand gradually may suggest a benign process. (5) In fact, an expansile growth with smooth borders is more common than infiltration into the surrounding tissues.

A diagnosis cannot be made on the basis of clinical and gross morphologic characteristics; a careful histologic examination and reticulum staining are required. (7) Biopsies should be performed carefully because of the high risk of bleeding. (13)

Pathology. Some authors believe that the composition of sinonasal hemangiopericytomas is different from that of hemangiopericytomas that arise in other areas. (14,15) Sinonasal tumors contain uniform oval or spindle-shaped cells that form tight aggregates with only a small amount of intervening collagenous stroma (figure 5, A). (16) Mitoses are rare and necrosis is absent. The vasculature is dilated with "staghorn-like" vascular spaces.

[FIGURE 5 OMITTED]

The neoplastic cells do not stain for epithelial, melanocytic, or neural markers. A finding of positive staining for cytokeratin excludes a diagnosis of hemangiopericytoma. The tumor cells are typically positive for vimentin (98% of specimens) and smooth-muscle actin (92%) stains. (11) Special stains for reticulin show positivity surrounding individual tumor cells throughout the entire tumor (figure 5, B). On electron microscopy, some features--such as thin cytoplasmic filaments and pinocytic vesicles--suggest pericytic differentiation (figure 5, C). (15)

Imaging features. Plain radiographs of the sinonasal area are of limited diagnostic value, although they may suggest the presence of a space-occupying lesion with a mass effect that distorts the adjacent bony structures. (6)

CT clearly demonstrates tumor involvement of soft tissues of the nasal cavity and paranasal sinuses that may enhance after intravenous contrast administration. (8,17) With large lesions, CT can clearly demonstrate bone destruction in the nasal cavity, paranasal sinuses, and adjacent orbital and intracranial structures. (12)

On MRI, sinonasal hemangiopericytomas appear as solid masses with isointense signals on T1-weighted imaging with diffuse enhancement after intravenous administration of gadolinium; on T2-weighted imaging, they reflect isointense to low-intensity signals. (8,17) MRI is of value in differentiating tumor tissue from inflammatory fluid caused by sinus obstruction. Contrast-enhanced MRI is the best means of demonstrating tumor extension to the base of the skull. (5,6-8,12,17) In highly vascularized tumors, voids in vascular signal flow may also be seen on MRI. (5) However, on postcontrast MRI, inflammation of the normal mucosa adjacent to the tumor sometimes enhances, which can lead to an overestimation of the size and extension of the tumor. (8)

Conventional digital angiography may be the best method of demonstrating the vascular supply to the tumor in order to plan preoperative embolization. (8,10,17) Imaging of sinonasal hemangiopericytomas may be nonspecific, and these lesions should be differentiated from other types of tumors that involve the sinonasal area, such as esthesioneuroblastomas, adenoid cystic carcinomas, squamous cell carcinomas, and nasopharyngeal angiofibromas, among others. (9,10)

Management. Wide local excision is the treatment of choice, but adequate negative surgical margins are usually difficult to achieve in the sinonasal area. (5,7,9) Endoscopic resection might be adequate when the lesion is small and its site of origin is definitively identified. (5) A craniofacial approach is necessary when the cribriform plate or the base of the skull is breached. (6) Although radiation therapy has been used for both adjuvant treatment and palliation, it is not clear whether it is better than surgery alone in terms of improving survival. (5,7,8)

Reported rates of metastasis for all hemangiopericytomas vary greatly, ranging from 12 to 60%; most metastases occur in the lungs and skeleton. (7,8,17) The reported rates for sinonasal hemangiopericytomas are generally lower, ranging from 5 to 10%. (7,8,17)

Recurrence has been reported to precede the development of metastasis. (7,9) Local recurrence rates for sinonasal hemangiopericytomas range from 8 to 53%; most recurrences are probably the result of inadequate surgical excisions. (5-9) Because recurrence can develop years after treatment, lifelong follow-up must be observed. (5-9)

References

(1.) Stout AP, Murray MR. Hemangiopericytoma: A vascular tumor featuring Zimmerman's pericytes. Ann Surg 1942;116:26-33.

(2.) Zimmerman KW. Der feinere bau der blutcapillaren. Z Anat Entwicklungsgesch 1923;68:29-109.

(3.) Millman B, Brett D, Vrabec DP. Sinonasal hemangiopericytoma. Ear Nose Throat J 1994;73:680-2, 687.

(4.) Hekkenberg RJ, Davidson J, Kapusta L, et al. Hemangiopericytoma of the sinonasal tract. J Otolaryngol 1997;26:277-80.

(5.) Bhattacharyya N, Shapiro NL, Metson R. Endoscopic resection of a recurrent sinonasal hemangiopericytoma. Am J Otolaryngol 1997;18:341-4.

(6.) Boey HP, Mitra S, Yanagisawa E. Intranasal hemangiopericytoma. Ear Nose Throat J 1998;77:944-5.

(7.) Reiner SA, Siegel GJ, Clark KF, Min KW. Hemangiopericytoma of the nasal cavity. Rhinology 1990;28:129-36.

(8.) Herve S, Abd Alsamad I, Beautru R, et al. Management of sinonasal hemangiopericytomas. Rhinology 1999;37:153-8.

(9.) Catalano PJ, Brandwein M, Shah DK, et al. Sinonasal hemangiopericytomas: A clinicopathologic and immunohistochemical study of seven cases. Head Neck 1996;18:42-53.

(10.) Weber W, Henkes H, Metz KA, et al. Haemangiopericytoma of the nasal cavity. Neuroradiology 2001;43:183-6.

(11.) Thompson LD, Miettinen M, Wenig BM. Sinonasal-type hemangiopericytoma: A clinicopathologic and immunophenotypic analysis of l04 cases showing perivascular myoid differentiation. Am J Surg Pathol 2003;27:737-49.

(12.) Morrison DA, Bibby K. Sellar and suprasellar hemangiopericytoma mimicking pituitary adenoma. Arch Ophthalmol 1997;115:1201-3.

(13.) Stout AP. Hemangiopericytoma: A study of 25 new cases. Cancer 1949;2:1027-35.

(14.) Compagno J, Hyams VJ. Hemangiopericytoma-like intranasal tumors. A clinicopathologic study of 23 cases. Am J Clin Pathol 1976;66:672-83.

(15.) Watanabe K, Saito A, Suzuki M, et al. True hemangiopericytoma of the nasal cavity. Arch Pathol Lab Med 2001;125:686-90.

(16.) Mills SE, Gaffey MJ, Frierson HF. Tumors of the upper aerodigestive tract and ear. In: Atlas of Tumor Pathology. 3rd series. Fascicle 26. Washington, D.C.: Armed Forces Institute of Pathology, 2000: 248.

(17.) Ravenel JG, Goodman PC. Late pulmonary metastases from hemangiopericytoma of the mandible: Unusual findings on CT and MR imaging. AJR Am J Roentgenol 2001;177:244-5.

From the Department of Radiology (Dr. Palacios, Dr. Restrepo, Dr. Mastrogiovanni, and Dr. Rojas) and the Department of Pathology (Dr. Lorusso), Louisiana State University Health Sciences Center, New Orleans.

Reprint requests: Enrique Palacios, MD, Department of Radiology, LSUHSC, 1542 Tulane Ave., New Orleans, LA 70112. Phone: [phone]; fax: [phone]; e-mail: [e-mail]