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Hemangiopericytoma of the parapharyngeal space
Hemangiopericytoma of the parapharyngeal space JOSÉ L. LLORENTE, MD, CARLOS SUÁREZ, MD, PILAR ABLANEDO, MD, MARCOS CARREÑO, MD, JUAN C. ALVAREZ, MD, and JUAN P. RODRIGO, MD, Oviedo, Asturias, Spain
H
emangiopericytoma is a vascular tumor originating from the pericytes that surround the capillaries. The tumor occurs anywhere in the body; the head and neck, the nasal cavity, and the paranasal sinuses are most often involved. The clinical presentation is nonspecific. Diagnostic imaging is helpful in narrowing the differential diagnoses, delineating the extent of tumor spread, and planning the surgical approach. Definitive diagnosis is made only by careful histologic examination. Treatment with radical surgery, if possible, is effective, and preoperative embolization can reduce the risk of hemorrhage. CASE REPORT At presentation a 22-year-old woman had a nearly 1-year history of slight pharyngeal pain after an upper respiratory viral infection. The patient denied other symptoms such as neurologic deficits, dysphagia, otalgia, or trismus. Examination of the nasopharynx under general anesthesia revealed a soft, round tumor on the right side that obscured the right choana beneath an intact mucosa. A biopsy specimen was taken at another institution, resulting in severe bleeding that required posterior nasal packing. The patient was then referred to our hospital with a diagnosis of parapharyngeal hemangiopericytoma. At our institution the physical examination revealed a nontender mass displacing the lateral wall of the oropharynx and the tonsillar region, enlarging superiorly and projecting the lateral nasopharyngeal wall. The overlying pharyngeal mucosa was normal with a scar just below the Rosenmüller fossa. The cervical nodes were not palpable. The rest of the examination and routine test results were unremarkable. As other authors1,2 have pointed out, CT scans do not show any characteristics that indicate the pathologic nature of the tumor. In our case, an MRI of the head demonstrated a wellcircumscribed mass in the parapharyngeal space, separated from the carotid artery, the internal jugular vein, and the skull base. The lateral wall of the pharynx was mildly displaced by the mass. Axial T1-weighted images demonstrated hypointense signals, whereas coronal T2-weighted images had high From the Departments of ENT (Drs Llorente, Suárez, Carreño, Alvarez, and Rodrigo) and Pathology (Dr Ablanedo), Hospital Central de Asturias, Universidad de Oviedo. Reprint requests: José Luis Llorente Pendás, c/Picayón n° 23, 33006, Oviedo, Asturias, Spain. Otolaryngol Head Neck Surg 1999;120:531-3. Copyright © 1999 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/99/$8.00 + 0 23/78/82443
signal intensities in the tumor (Fig 1). In both, vascular flow voids were present. After gadolinium administration, the signal from the lesion was enhanced. Superselective angiography clearly demonstrated an extensive vascular network with a main feeding vessel: the ascending pharyngeal artery (Fig 2). Embolization of this vessel was done 1 day before surgery, and postembolization angiogram showed that tumor blush was almost completely absent (Fig 3). A cervical-parotid approach was carried out with, a cervical incision in a standard parotidectomy fashion. The main trunk of the facial nerve was identified, and the digastric, stylohyoid, and styloglossus muscles were divided. The styloid process was removed, and the external carotid artery and the ascending pharyngeal artery were tied. The mass was then dissected and completely excised, including the lateral nasopharyngeal wall where the tumor was adherent, although with no clear infiltration. Peroperative frozen-section biopsy specimens showed free margins in the nasopharyngeal mucosa. Closure was achieved primarily and reinforced by the superior pharyngeal constrictor muscle. All cranial nerves, the internal carotid artery, the internal jugular vein, and the cervical sympathetic chain were preserved. Postoperative recovery was uneventful except for a slight paresis of the marginal mandibular branch of facial nerve. which recovered completely after 4 weeks. The patient showed no recurrence after 2 years, and at present she is free of symptoms. The resected specimen consisted of a piece of soil tissue, measuring approximately 5 × 4 cm. Microscopic examination showed uniform vascular spaces throughout the tumor, lined by well-differentiated endothelial cells that were surrounded by tightly spindle-shaped cells, with an area of central necrosis. No mitotic figures were noted in any of the sections examined. Most tumor cells were weakly positive to vimentin. There was no reactivity with S-100 protein, factor VIII, actin, or cytokeratin. DISCUSSION Hemangiopericytoma of the head and neck can invade the parapharyngeal space,3 but primary hemangiopericytoma of the parapharyngeal space is a very rare neoplasm, and to our knowledge only few cases had been reported previously in the literature (Table 1). The parapharyngeal space shows a wide variety of neo531
532
Otolaryngology– Head and Neck Surgery April 1999
LLORENTE et al
Fig 1. Coronal T2-weighted MRI shows the tumor. Note tumor signal enhancement image.
Fig 3. Postembolization angiogram of ascending pharyngeal artery.
Table 1. Reported cases of hemangiopericytoma of the parapharyngeal space Author
Year
No. of patients
Histology
McIlrath et al11 McMaster et al12 Robb et al1 Kairemo et al8 Rosignoli et al13 Daniels et al2 Llorente et al
1963 1975 1987 1991 1993 1996 1996
1 2* 1 1 1 1 1
Unknown Unknown Malignant Malignant Benign Benign Benign
*Might
Fig 2. Superselective angiography demonstrates a highly vascularized tumor in the parapharyngeal region. Tumor is fed almost exclusively by the right ascending pharyngeal artery.
plastic tumors, but overall approximately 50% of tumors are of salivary gland origin.4 Clinical detection of parapharyngeal space tumors in early stages usually is not possible, and physical examination is unreliable in predicting origin, vascularity, and relationship to the great vessels.4 It has been reported that
include same patient as in McIlrath’s series.
all the masses bulging in the oropharyngeal area were larger than 3 cm,5 and 20% of these masses were found incidentally during routine physical examination.4 However, CT and MRI are currently accurate in determining the origin of hemangiopericytoma. The use of contrast during CT imaging ascertains the vascularity of the tumor,5 and it is very helpful in the evaluation of bony erosion. MRI provides the most useful preoperative information about the extent of the tumor and its relationship to surrounding structures and distinguishes between intraparotid and extraparotid neoplasms. MRI demonstrates increased signal on T2-weighted images and isointensity on T1-weighted images.2 Angiography is recommended for all enhancing lesions to confirm the diagnosis of a vascular neoplasm and allows preoperative definition of the blood supply and embolization of the tumor.6 It is possible that magnetic resonance angiography may replace formal angiography in the future for many lesions.7 Other specific imaging tests, such as radioimmunoscintigraphy with
Otolaryngology– Head and Neck Surgery Volume 120 Number 4
indium-111–labeled monoclonal anticarcinoembryonal antigen antibody, have been recommended.8 According to Carrau et al,4 the use of embolization in vascular tumors is controversial because it may produce a severe inflammatory reaction around the tumor (especially in paragangliomas). However, in our patient the embolization was performed 1 day before surgery, and it was very helpful in decreasing the size of the tumor, reducing the blood loss, and making the surgery safer. Although transoral or transnasal biopsy before surgery is contraindicated for most parapharyngeal space tumors, it was performed in this patient. This technique causes the pharyngeal mucosa to adhere to the tumor capsule, and subsequent removal is more difficult and increases morbidity. In addition, there is a risk of hemorrhage and tumor rupture, with a greater risk of subsequent recurrent lesions.7 Fine-needle aspiration transorally (guided by ultrasound or CT scan if necessary) is an alternative option but is unnecessary when a vascular tumor is suspected. The definitive treatment is surgical resection with adequate margins. In agreement with most authors, we have used an external approach (cervical-parotid approach) to get adequate tumor visualization and wide control of the surrounding nerves and vessels. Diagnostic imaging techniques are very helpful in planning the surgical approach and showing extent of the tumor spread and the relationships with adjacent structures. In view of the pathologic nature of the tumor, adjuvant radiotherapy was not indicated. However, some authors recommend postoperative irradiation in case of a high mitotic rate or when a malignant behavior is suspected.3,9 The median follow-up of our patient was only 2 years. During this period the patient remained well and free from recurrence or metastatic disease. Prognosis depends on many factors, including histologic grading, age, and location of the tumor,2 and it could be appropriate to consider all hemangiopericytomas as potentially malignant,l0 Thus lifetime clin-
LLORENTE et al
533
ical and radiologic (CT/MRI) follow-up is warranted because late recurrences have been reported. We thank Drs Rubio and Rama (Hospital Valdecilla Santander) for referral of the patient and Drs Quintana, Canga, and Cerezal for the radiographic studies and the embolization of the tumor. REFERENCES 1. Robb PJ, Singh S, Hartley RB, et al. Malignant hemangiopericytoma of the parapharyngeal space. Head Neck Surg 1987;9:17983. 2. Daniels RL, Haller JR, Harnsberger HR. Imaging case study of the month. Hemangiopericytoma of the masticator space. Ann Otol Rhinol Laryngol 1996;105:162-5. 3. Katsantonis GP, Friedman WH, Rosenblum BN. The surgical management of advanced malignancies of the parotid gland. Otolaryngol Head Neck Surg 1989;101:633-40. 4. Carrau RL, Myers EN, Johnson JT. Management of tumors arising in the parapharyngeal space. Laryngoscope 1990;100:583-9. 5. Som PM, Biller HF, Lawson W, et al. Parapharyngeal space masses: an updated protocol-based upon 104 cases. Radiology 198;153:149-56. 6. Miller FR, Wanamaker JR, Lavertu P, et al. Magnetic resonance imaging and the management of parapharyngeal space tumors. Head Neck 1996;18:67-77. 7. Olsen KD. Tumors and surgery of the parapharyngeal space. Laryngoscope Suppl 1994;104:1-28. 8. Kairemo KJA, Hopsu EVM, Melartin EJ, et al. Imaging of a parapharyngeal hemangiopericytoma. Radioimmunoscintigraphy (SPECT) with indium-111 labeled anti-CEA antibody, and comparison to digital subtraction angiography, computed tomography, and immunohistochemistry. Cancer 1991;67:61-6. 9. Weber BP, Schrader M, Inniger R. Maligne Hamangioperizytome im Kopf-Hals-Bereich. HNO 1990;38:326-33. 10. Philippou S, Gellrich NC. Hemangiopericytoma of the head and neck region. A clinical and morphological study of three cases. Int J Oral Maxillofac Surg 1992;21:99-103. 11. McIlrath DC, ReMine WH, Devine KD, et al. Tumors of the parapharyngeal region. Surg Gynecol Obstet 1963;116:88-94. 12. McMaster MJ, Soule EH, Ivins JC. Hemangiopericytoma. A clinicopathologic study and long-term follow-up of 60 patients. Cancer 1975;36:2232-44. 13. Rosignoli M, Cadoni G, Rabitti C, et al. Emangiopericitoma Dello spazio parafaringeo. Acta Otorhinol Ital 1993;13:455-65.
H
emangiopericytoma is a vascular tumor originating from the pericytes that surround the capillaries. The tumor occurs anywhere in the body; the head and neck, the nasal cavity, and the paranasal sinuses are most often involved. The clinical presentation is nonspecific. Diagnostic imaging is helpful in narrowing the differential diagnoses, delineating the extent of tumor spread, and planning the surgical approach. Definitive diagnosis is made only by careful histologic examination. Treatment with radical surgery, if possible, is effective, and preoperative embolization can reduce the risk of hemorrhage. CASE REPORT At presentation a 22-year-old woman had a nearly 1-year history of slight pharyngeal pain after an upper respiratory viral infection. The patient denied other symptoms such as neurologic deficits, dysphagia, otalgia, or trismus. Examination of the nasopharynx under general anesthesia revealed a soft, round tumor on the right side that obscured the right choana beneath an intact mucosa. A biopsy specimen was taken at another institution, resulting in severe bleeding that required posterior nasal packing. The patient was then referred to our hospital with a diagnosis of parapharyngeal hemangiopericytoma. At our institution the physical examination revealed a nontender mass displacing the lateral wall of the oropharynx and the tonsillar region, enlarging superiorly and projecting the lateral nasopharyngeal wall. The overlying pharyngeal mucosa was normal with a scar just below the Rosenmüller fossa. The cervical nodes were not palpable. The rest of the examination and routine test results were unremarkable. As other authors1,2 have pointed out, CT scans do not show any characteristics that indicate the pathologic nature of the tumor. In our case, an MRI of the head demonstrated a wellcircumscribed mass in the parapharyngeal space, separated from the carotid artery, the internal jugular vein, and the skull base. The lateral wall of the pharynx was mildly displaced by the mass. Axial T1-weighted images demonstrated hypointense signals, whereas coronal T2-weighted images had high From the Departments of ENT (Drs Llorente, Suárez, Carreño, Alvarez, and Rodrigo) and Pathology (Dr Ablanedo), Hospital Central de Asturias, Universidad de Oviedo. Reprint requests: José Luis Llorente Pendás, c/Picayón n° 23, 33006, Oviedo, Asturias, Spain. Otolaryngol Head Neck Surg 1999;120:531-3. Copyright © 1999 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/99/$8.00 + 0 23/78/82443
signal intensities in the tumor (Fig 1). In both, vascular flow voids were present. After gadolinium administration, the signal from the lesion was enhanced. Superselective angiography clearly demonstrated an extensive vascular network with a main feeding vessel: the ascending pharyngeal artery (Fig 2). Embolization of this vessel was done 1 day before surgery, and postembolization angiogram showed that tumor blush was almost completely absent (Fig 3). A cervical-parotid approach was carried out with, a cervical incision in a standard parotidectomy fashion. The main trunk of the facial nerve was identified, and the digastric, stylohyoid, and styloglossus muscles were divided. The styloid process was removed, and the external carotid artery and the ascending pharyngeal artery were tied. The mass was then dissected and completely excised, including the lateral nasopharyngeal wall where the tumor was adherent, although with no clear infiltration. Peroperative frozen-section biopsy specimens showed free margins in the nasopharyngeal mucosa. Closure was achieved primarily and reinforced by the superior pharyngeal constrictor muscle. All cranial nerves, the internal carotid artery, the internal jugular vein, and the cervical sympathetic chain were preserved. Postoperative recovery was uneventful except for a slight paresis of the marginal mandibular branch of facial nerve. which recovered completely after 4 weeks. The patient showed no recurrence after 2 years, and at present she is free of symptoms. The resected specimen consisted of a piece of soil tissue, measuring approximately 5 × 4 cm. Microscopic examination showed uniform vascular spaces throughout the tumor, lined by well-differentiated endothelial cells that were surrounded by tightly spindle-shaped cells, with an area of central necrosis. No mitotic figures were noted in any of the sections examined. Most tumor cells were weakly positive to vimentin. There was no reactivity with S-100 protein, factor VIII, actin, or cytokeratin. DISCUSSION Hemangiopericytoma of the head and neck can invade the parapharyngeal space,3 but primary hemangiopericytoma of the parapharyngeal space is a very rare neoplasm, and to our knowledge only few cases had been reported previously in the literature (Table 1). The parapharyngeal space shows a wide variety of neo531
532
Otolaryngology– Head and Neck Surgery April 1999
LLORENTE et al
Fig 1. Coronal T2-weighted MRI shows the tumor. Note tumor signal enhancement image.
Fig 3. Postembolization angiogram of ascending pharyngeal artery.
Table 1. Reported cases of hemangiopericytoma of the parapharyngeal space Author
Year
No. of patients
Histology
McIlrath et al11 McMaster et al12 Robb et al1 Kairemo et al8 Rosignoli et al13 Daniels et al2 Llorente et al
1963 1975 1987 1991 1993 1996 1996
1 2* 1 1 1 1 1
Unknown Unknown Malignant Malignant Benign Benign Benign
*Might
Fig 2. Superselective angiography demonstrates a highly vascularized tumor in the parapharyngeal region. Tumor is fed almost exclusively by the right ascending pharyngeal artery.
plastic tumors, but overall approximately 50% of tumors are of salivary gland origin.4 Clinical detection of parapharyngeal space tumors in early stages usually is not possible, and physical examination is unreliable in predicting origin, vascularity, and relationship to the great vessels.4 It has been reported that
include same patient as in McIlrath’s series.
all the masses bulging in the oropharyngeal area were larger than 3 cm,5 and 20% of these masses were found incidentally during routine physical examination.4 However, CT and MRI are currently accurate in determining the origin of hemangiopericytoma. The use of contrast during CT imaging ascertains the vascularity of the tumor,5 and it is very helpful in the evaluation of bony erosion. MRI provides the most useful preoperative information about the extent of the tumor and its relationship to surrounding structures and distinguishes between intraparotid and extraparotid neoplasms. MRI demonstrates increased signal on T2-weighted images and isointensity on T1-weighted images.2 Angiography is recommended for all enhancing lesions to confirm the diagnosis of a vascular neoplasm and allows preoperative definition of the blood supply and embolization of the tumor.6 It is possible that magnetic resonance angiography may replace formal angiography in the future for many lesions.7 Other specific imaging tests, such as radioimmunoscintigraphy with
Otolaryngology– Head and Neck Surgery Volume 120 Number 4
indium-111–labeled monoclonal anticarcinoembryonal antigen antibody, have been recommended.8 According to Carrau et al,4 the use of embolization in vascular tumors is controversial because it may produce a severe inflammatory reaction around the tumor (especially in paragangliomas). However, in our patient the embolization was performed 1 day before surgery, and it was very helpful in decreasing the size of the tumor, reducing the blood loss, and making the surgery safer. Although transoral or transnasal biopsy before surgery is contraindicated for most parapharyngeal space tumors, it was performed in this patient. This technique causes the pharyngeal mucosa to adhere to the tumor capsule, and subsequent removal is more difficult and increases morbidity. In addition, there is a risk of hemorrhage and tumor rupture, with a greater risk of subsequent recurrent lesions.7 Fine-needle aspiration transorally (guided by ultrasound or CT scan if necessary) is an alternative option but is unnecessary when a vascular tumor is suspected. The definitive treatment is surgical resection with adequate margins. In agreement with most authors, we have used an external approach (cervical-parotid approach) to get adequate tumor visualization and wide control of the surrounding nerves and vessels. Diagnostic imaging techniques are very helpful in planning the surgical approach and showing extent of the tumor spread and the relationships with adjacent structures. In view of the pathologic nature of the tumor, adjuvant radiotherapy was not indicated. However, some authors recommend postoperative irradiation in case of a high mitotic rate or when a malignant behavior is suspected.3,9 The median follow-up of our patient was only 2 years. During this period the patient remained well and free from recurrence or metastatic disease. Prognosis depends on many factors, including histologic grading, age, and location of the tumor,2 and it could be appropriate to consider all hemangiopericytomas as potentially malignant,l0 Thus lifetime clin-
LLORENTE et al
533
ical and radiologic (CT/MRI) follow-up is warranted because late recurrences have been reported. We thank Drs Rubio and Rama (Hospital Valdecilla Santander) for referral of the patient and Drs Quintana, Canga, and Cerezal for the radiographic studies and the embolization of the tumor. REFERENCES 1. Robb PJ, Singh S, Hartley RB, et al. Malignant hemangiopericytoma of the parapharyngeal space. Head Neck Surg 1987;9:17983. 2. Daniels RL, Haller JR, Harnsberger HR. Imaging case study of the month. Hemangiopericytoma of the masticator space. Ann Otol Rhinol Laryngol 1996;105:162-5. 3. Katsantonis GP, Friedman WH, Rosenblum BN. The surgical management of advanced malignancies of the parotid gland. Otolaryngol Head Neck Surg 1989;101:633-40. 4. Carrau RL, Myers EN, Johnson JT. Management of tumors arising in the parapharyngeal space. Laryngoscope 1990;100:583-9. 5. Som PM, Biller HF, Lawson W, et al. Parapharyngeal space masses: an updated protocol-based upon 104 cases. Radiology 198;153:149-56. 6. Miller FR, Wanamaker JR, Lavertu P, et al. Magnetic resonance imaging and the management of parapharyngeal space tumors. Head Neck 1996;18:67-77. 7. Olsen KD. Tumors and surgery of the parapharyngeal space. Laryngoscope Suppl 1994;104:1-28. 8. Kairemo KJA, Hopsu EVM, Melartin EJ, et al. Imaging of a parapharyngeal hemangiopericytoma. Radioimmunoscintigraphy (SPECT) with indium-111 labeled anti-CEA antibody, and comparison to digital subtraction angiography, computed tomography, and immunohistochemistry. Cancer 1991;67:61-6. 9. Weber BP, Schrader M, Inniger R. Maligne Hamangioperizytome im Kopf-Hals-Bereich. HNO 1990;38:326-33. 10. Philippou S, Gellrich NC. Hemangiopericytoma of the head and neck region. A clinical and morphological study of three cases. Int J Oral Maxillofac Surg 1992;21:99-103. 11. McIlrath DC, ReMine WH, Devine KD, et al. Tumors of the parapharyngeal region. Surg Gynecol Obstet 1963;116:88-94. 12. McMaster MJ, Soule EH, Ivins JC. Hemangiopericytoma. A clinicopathologic study and long-term follow-up of 60 patients. Cancer 1975;36:2232-44. 13. Rosignoli M, Cadoni G, Rabitti C, et al. Emangiopericitoma Dello spazio parafaringeo. Acta Otorhinol Ital 1993;13:455-65.