Applied Radiology

Prepared by Lewis Shin, BS and Glenn Tung, MD of the Department of Diagnostic Imaging, Brown University School of Medicine, Providence, RI.

CASE SUMMARY

The patient is a 19-year-old man with a 10-month history of nasal congestion and worsening epistaxis for the past 3 months. Previous medical history is significant for bilateral retinoblastoma at age 3 that was treated with left eye enucleation and ocular implant, and conventional radiation treatment of the right globe. Computed tomography (CT), enhanced magnetic resonance (MR) imaging, MR angiography, and conventional catheter angiography were performed.

DIAGNOSIS

Juvenile nasopharyngeal angiofibroma (JNA) of the nasal cavity.

IMAGING FINDINGS

A left eye prosthesis and calcification of the right globe is consistent with treated bilateral retinoblastoma (figure 1). A large, enhancing nasal cavity mass extending into the nasopharynx with feeding vessels from branches of the left external carotid artery was found (figures 2 and 3).

DISCUSSION

Juvenile nasopharyngeal angiofibroma constitutes < 0.5% of all head and neck neoplasms. It is a histologically benign, yet locally aggressive, vascular tumor that occurs most frequently in males from 5 to 25 years of age. Complications occur when there is local invasion of surrounding tissues. The most common route of local spread is medially through the sphenopalantine foramen to the posterior oropharynx and nasal cavity. Consequently, JNA should be suspected in a boy or adolescent male with a history of chronic nasal obstruction or recurrent, atraumatic epistaxis and a soft-tissue mass in the nose or nasopharynx. ¹

Diagnostic imaging should be performed prior to an invasive procedure since it may suggest the diagnosis, thereby reducing the risk of catastrophic hemorrhage associated with biopsy. In a study of 72 patients, Lloyd et al ¹ report three findings on CT and MR imaging that should suggest a diagnosis of JNA: 1) a soft-tissue mass in the nasopharynx or nasal cavity; 2) a mass in the pterygopalatine fossa; and 3) erosion of posterior osseous margin of the sphenopalantine foramen extending to the base of the medial pterygoid plate. In addition, JNA can grow into the maxillary and sphenoid sinuses, orbit, and central skull base. ² There have been rare reports of JNA originating in the maxillary and sphenoid sinuses. ^3,4 On CT, bone involvement can best be seen on thin-section axial or coronal images. On MR imaging, JNA appears as a heterogeneous mass with signal voids that are consistent with the highly vascular tumor; intense enhancement with gadopentetate contrast material is typical (figure 2). ^1,2

The differential diagnosis for this large nasal mass includes antrochoanal polyp; inflammatory sinonasal polyp; neurofibroma; adenoidal hypertrophy; and malignant neoplasm, such as nasopharyngeal carcinoma, lymphoma, or rhabdomyosarcoma. CT and MR imaging of nasopharyngeal carcinoma show an inhomogeneous mass arising from the nasopharyngeal mucosa or submucosal space with skull-base erosion or intracranial extension. ² Lymphoma may arise from adenoidal tissues of the nasopharynx or Waldeyer's ring and can be associated with lymphadenopathy. Imaging of rhabdomyosarcoma reveals a soft-tissue mass with frequent bone destruction and mild enhancement on CT, but marked enhancement on MR imaging. ²

The carcinogenic effects of radiation therapy have been confirmed since the classic study of radiogenic osteosarcoma by Cahan et al. ⁵ Four criteria were cited in this study for a tumor to be considered radiation-induced. These criteria include: 1) absence of microscopic and radiographic evidence of malignancy prior to radiation treatment; 2) development of the tumor in the field of radiation treatment; 3) a relatively long latency (exceeding 5 years) between treatment and discovery of tumor; and 4) histologic confirmation of the tumor. ⁵ Sarcoma is the most common malignant, radiation-induced neoplasm; most often, osteosarcoma in bone and malignant fibrous histiocytoma in soft tissue. The most common benign radiogenic tumor is osteochondroma. ⁶ This case of JNA fulfills the criteria for radiogenic tumor, since it arose in the treatment field 16 years following conventional radiation therapy for retinoblastoma. Furthermore, there was no radiologic or histologic evidence of a naso-pharyngeal tumor prior to radiotherapy.

Interestingly, patients with retinoblastoma are at increased risk for developing a second primary tumor even without radiation treatment. Even though the majority of cases of retinoblastoma are unilateral, the majority of second neoplasms arise in patients with bilateral retino-blastoma. ⁷ This risk of second tumors is increased even further in patients receiving radiation therapy. In a study of 688 patients with retinoblastoma, tumors that developed in the field of radiation treatment included 24 cases of osteosarcoma, 6 cases of fibrosarcoma, and 5 cases of soft tissue sarcoma; no cases of juvenile angiofibroma were reported. ⁸

In conclusion, we believe that this may represent a rare case of radiogenic angio-fibroma following radiation treatment of bilateral retinoblastoma. However, we cannot exclude the alternative that it represents the rare occurrence of two unusual diseases in the same patient.

REFERENCES

1. Lloyd G, Howard D, Phelps P, Cheesman A: Juvenile angiofibroma: The lessons of 20 years of modem imaging. J Laryngol Otol 113:127-134, 1999.

2. Som PM, Curtin HD: Head and Neck Imaging. St. Louis, Mosby,1996.

3. Kitano M, Landini G, Mimura T: Juvenile angiofibroma of the maxillary sinus. Int J Oral Maxillofac Surg 21:230-232, 1992.

4. Tsunoda A, Kohda H, Ishikawa N, Komatsuzaki A: Juvenile angiofibroma, limited to the sphenoid sinus. J Otolaryngol 27:37-39, 1998.

5. Cahan WG, Woodward HQ, Higinbotham NL, et al: Sarcoma arising in irradiated bone. Cancer 1:3-29, 1948.

6. Rabin BM, Meyer JR, Berlin JW, et al: Radiation-induced changes in the central nervous system and head and neck. Radiographics 16:1055-1072, 1996.

7. Abramson DH, Ellsworth RM, Zimmerman LE: Nonocular cancer in retinoblastorna survivors. Trans Am Acad Ophthalmol Otolaryngol 81:454-457, 1976.

8. Abramson DH, Ellsworth RM, Kitchin FD, Tung G: Second nonocular tumors in retinoblastoma survivors: Are they radiation induced? Ophthalmol 91:1351-1355, 1984.