Eosinophilic Angiocentric Fibrosis: An Unusual Entity of the Sinonasal Tract

Eosinophilic angiocentric fibrosis (EAF) is a very rare neoplasm of the sinonasal tract and the upper respiratory system. It was first described by Roberts and McCann in a case report of 3 patients and in a postscript of 2 additional patients in 1985 and 1997, respectively.1,2 To our knowledge, not more than 10 new cases have been reported in the English language literature since those initial descriptions.3–9 In the opinion of several authors, this mucosal fibrotic lesion is a variant of granuloma faciale, owing to the histologic similarities between the 2 lesions.1,3 The exact mechanism of the neoplasm and its relation with other diseases are still being debated. We report a new case of EAF in a 45-year-old man.

A 45-year-old man presented with bilateral nasal obstruction. He had had this complaint since his adolescence. He had no known history of allergy or any other significant disease. Nasal obstruction occurred periodically. He had been given allergy medications, but only symptomatic relief was obtained. After worsening of the symptoms, he underwent an operation and nasal septoplasty was performed.

The surgical specimen consisted of the nasal septum and irregular, mucosal, polypoid tissues. The cut surface of the nasal septum was firm, fibrotic, and white. Histologically, a very dense fibrotic stroma was observed beneath an intact surface mucosa. Thick collagen bundles characteristically showed an onionskin appearance due to concentric perivascular whorling, resulting in obliteration of vessels in their centers. Within the stroma were scattered polymorphous inflammatory cells, including eosinophils (Figure 1). Trichrome stain highlighted collagen whorls around vessels (Figure 2). There was neither necrosis nor granuloma formation. No destruction or fibrin deposition was observed in vessel walls. All these microscopic findings corresponded to the typical features of EAF that have been reported previously in the literature.

Eosinophilic angiocentric fibrosis is a very rare fibrosing lesion of the sinonasal tract. It is most commonly seen in the nasal septum and sinus mucosae. One case has been reported in the larynx.4 Patients are mostly women and are approximately 40 years of age. To our knowledge, the literature contains only 13 previous case reports, 9 of which involved women. The mean age of these patients was 44 years. The pathogenesis of EAF is not well known. A probable allergic origin is suggested because of such history in some patients and the typical eosinophil-rich inflammatory reaction that is present in all patients. Our patient had no significant past history or known allergic condition. Laboratory tests, however, could not be performed. Eosinophilic angiocentric fibrosis is also considered to be a mucosal variant of granuloma faciale, owing to the histologic similarities between these 2 entities3 and its association with granuloma faciale in some cases.1,5 

The histologic appearance of the neoplasm seems to be unique. Thick collagen bundles that whorl around vessels, an inflammatory reaction that is rich in eosinophils, and a fibrotic stroma are highly characteristic of this lesion. Some lesions that mimic EAF, however, must be ruled out. Granuloma faciale, an inflammatory vascular reaction, presents clinically as papules that are localized almost always on the face. Histologically, there is a polymorphous inflammatory infiltrate and it consists in large part of neutrophils and eosinophils, mainly in the dermis. Vasculitis, with deposition of fibrinoid material within the vessel walls is seen frequently, which has never been reported in EAF. On the other hand, characteristic perivascular collagen whorling is not a feature of granuloma faciale. Kimura disease may also mimic EAF, because of its proliferation of thin-walled vessels and tissue eosinophilia, but the typical microscopic features of EAF allow separation histologically.

Other systemic conditions, such as Wegener granulomatosis and Churg-Strauss syndrome, may warrant exclusion, particularly when any history of allergy is present or when specific laboratory values, such as serum antineutrophilic cytoplasmic antibodies or immunoglobulin E, are found to be high. One of the cases of EAF in the literature was reported to be associated with Wegener granulomatosis.6 The sinonasal tract is frequently the site of involvement for many granulomatous diseases, but no granuloma formation, giant cell histiocytic reaction, or necrosis is present in EAF.

The treatment of choice of EAF is not clear. Some symptomatic relief and local control may be obtained by corticosteroids and dapsone. While most patients had to undergo multiple resections, surgery alone may not be sufficient. Most of the patients described in the literature were reported to live with the disease.

It still remains unclear whether EAF is a separate entity with a characteristic histomorphology or whether it is associated with other systemic allergic disorders, which are not invariably present in all patients. More new cases are needed to clarify this issue.