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Page 8 of 18 Padoan et al. Vessel Plus 2021;5:41 https://dx.doi.org/10.20517/2574-1209.2021.41

color with petechial hemorrhages that resemble strawberries [61-64] . The differential diagnosis of mucosal
ulcers should include sarcoidosis, Crohn’s disease, infections (mycobacterial, leishmaniasis, and
[14]
paracoccidioidomycosis), and drug abuse . Finally, in GPA and other granulomatous infectious diseases,
[65]
palatal perforation is exceedingly unusual .

TUMOR-LIKE MANIFESTATIONS
Atypical lesions are often the presenting feature in GPA, including mass lesion. This manifestation may
present as parapharyngeal mass, parotid mass, sinonasal and maxillary sinus lesions, and subglottic
paratracheal mass [66-69] . Typically, masses are associated with PR3-ANCA and occur at early stage of the
disease, usually as part of a systemic disease (lung and kidney). Pseudotumor in the ENT region may
present with secondary cranial neuropathies. Nerve palsy may occur as single or multiple cranial nerve
involvement. Evolution to osteomyelitis by invasive mass is possible . Parapharyngeal involvement is
[70]
reported by description of a parapharyngeal mass or secondary to local extension from contiguous parotid
mass.

Tumor-like lesions in the ENT region are associated with a higher rate of partial response or refractory
disease. Furthermore, surgical procedures can be difficult in this region.

HISTOLOGICAL FINDINGS
As the nose and paranasal sinuses are frequently involved in AAV and easily accessible, an intranasal biopsy
is believed to be the one of the best ways to achieve histological confirmation. Thus, diagnostic biopsies of
the nasal mucosa can be performed under local anesthesia, being relatively minimally invasive; however, the
maxillary and ethmoid sinuses are also alternative regions for representative biopsies .
[14]

However, biopsy specimens from the ENT region are often small, making it therefore difficult to achieve a
conclusive histological diagnosis of AAV. It is recommended to take multiple large biopsies (> 5 mm) from
the edge of the inflamed area, in order to maximize the chance of obtaining a diagnostic biopsy . It is rare
[71]
to see at the same time all the typical features, including necrotizing granulomata with giant cells and
[72]
neutrophil-predominant vasculitis . Indeed, non-specific features, such as acute or chronic inflammation,
are usually found in most head and neck biopsy specimens, which does not help in confirming the diagnosis
of AAV . Only in up to 16% of GPA cases can the classic triad of vasculitis, necrosis, and granulomatous
[73]
inflammation be seen, while vasculitis and granulomas are found 21% of cases and vasculitic and necrosis in
23% of specimens . However, when the clinical picture fits the diagnosis of AAV despite a negative
[74]
histopathological result, a high index of suspicion must be preserved.

Although intranasal biopsies are the most common way to validate a diagnosis in GPA and EGPA,
intranasal biopsies from MPA patients seldom reveal the existence of vasculitis and therefore are of limited
[73]
value .
It is not recommended to perform biopsy of middle ear or mastoid region, given the technical difficulty of
obtaining an appropriate biopsy specimen and the high rate of inconclusive histological findings .
[74]

In EGPA patients, during the prodromal phase, it is extremely difficult to clearly distinguish chronic
rhinosinusitis from inflammation due to vasculitis. Histologically, nasal specimens usually show diffuse
eosinophilic tissue infiltration , as in eosinophilic-type nasal polyposis, while only less than 10% of
[75]
specimens reveal necrotizing vasculitis or eosinophilic granuloma. The diagnostic yield can be increased up
to 50% if histological examination is performed on deep biopsy or surgical specimens of sinus tissue