Many theories exist to explain the aetiology of ALHE. The main contention remains controversial whether it is a neoplastic or an atopic hypersensitivity reaction (unusual reactive process) with the latter receiving more support.9
Several reports also indicate the possibility that ALHE may be secondary to infection or trauma.9
However, the exact relationship of these lesions to each other, including Kimura’a disease, which represents an allergic or autoimmune response, remains incompletely understood.
First described in 1969 by Wells and Whimster,1
ALHE is a disfiguring lesion characterised by isolated or small numbers of pinkish to reddish-brown papules, frequently in the head and neck region. Although the range of diameters of lesions in ALHE is stated in dated literature between 1 and 10 cm,8
the vast majority of reported presentations are within 0.5 cm and 3 cm in diameter.7
Larger lesions, falling into the upper end of the spectrum are relatively rare, and as far as the authors could find have not been reported in the last 30-years.
Although our patient exhibited all of the cardinal and distinguishing histopathological features of ALHE, the initial diagnosis of ALHE was difficult because the lesion was exceptionally large, with no obvious surface changes. The lesion's clear demarcation, insidious growth, and sub-mucosal limitations indicated a benign neoplasia.7
Hence the differential diagnosis was primarily a mesenchymal tumour of the vessels, nerves or muscles in the head and neck, namely, neurilemmoma, leiomyoma, hemangioma, and fibrosarcoma.7
Though there are several treatment options, including intra-lesional injections of isotretinoin, glucocorticoids, interferon alpha-2a, cytotoxic agents, and irradiation therapy,9
the most effective therapy is complete excision and follow-up.1
Despite a 33% recurrence rate,9
our patient had a successful recovery with no recurrence in his 18-month follow-up.
ALHE has rarely been reported to exceed 3 cm in diameter, but based on our case report, it should be a viable differential diagnosis when encountering large subcutaneous tumours of the head & neck.