[Differential diagnosis of tumorous space-occupying lesions of the parotid gland: angiolymphoid hyperplasia with eosinophilia and Kimura disease].

Background: Subcutaneous mass lesions of the head and neck are common in angiolymphoid hyperplasia with eosinophilia (ALHE) as well as in Kimura's disease, most often in a periauricular location in young and middle aged adults. Often these benign angioproliferative lesions of unknown etiology will be misdiagnosed as parotid tumors although the majority are paraglandular. Whereas ill-defined lesions involving the parotid gland are frequently observed in Kimura's disease, only one case of intraparotid ALHE is reported in the literature.
Case Report: To this we add one further case: a 24-year-old man with a solid and well displaceable tumor of the left preauricular region. At ultrasound and intraoperatively we found a well demarcated tumor with high central vascularization surrounded by multiple networks of veins. One larger artery entered the lesion directly, visible as vascular structure on the cut surface. This blood vessel may have represented a vascular pattern (3 mm in diameter) that was identified as an artery by flow velocity measurement at duplex sonography. Histopathologically we saw the characteristic features of ALHE: numerous capillary proliferations showing prominent epithelioid endothelia cells with typical "hop nail" appearance, focal lympho-plasmacellular infiltrations and many eosinophils. The most conspicuous microscopic feature was a large thick-walled artery with total occlusions of the lumen that partially corresponded to duplex sonographic and macroscopic findings.
Conclusion: In our opinion, this may be indicative of a primary arterial disorder with secondary vascular proliferation and chronic inflammation. The treatment of choice is local excision with a safe margin of healthy tissue, since insufficient removal can result in recurrence.