LAUSR

Dear Editor Angiolymphoid hyperplasia with eosinophilia (ALHE) is a chronic, vasoproliferative disorder involving the skin and subcutaneous tissues. ALHE mainly occurs in the head and neck area, especially around the ears, forehead, and scalp. Since ALHE can develop in other area, such as the trunk and extremities, clinical diagnosis for ALHE with atypical presentation at the first visit is sometimes difficult for dermatologists. In this report, we described a case of multiple ALHE on the upper arm, and diagnosed by immunohistochemical staining focused on CD163+ MMP9+ M2 macrophages and CCL26. A 24-year-old Japanese man visited our outpatient clinic with multiple pruritic nodules on the right upper arm. He had been diagnosed with prurigo nodularis and treated with topical steroids by a private dermatologist without any improvement. On his initial visit, physical examination revealed multiple, disseminated purpuric to skincolored nodules on the right upper arm (Figure 1A,B). Dermoscopy findings revealed central epidermal necrosis and prominent radiating vessels on the papules (Figure 1C). A full blood count and biochemical profile revealed eosinophilia (11.4%) (<8.5%), although the IgE level (69 IU/mL [<170]) and serum CCL17/TARC level (387 pg/mL [<449]) were within normal ranges. Histopathological findings revealed multiple small vessels and proliferation of lymphatic vessels and small blood vessels in the dermis (Figure 2A). There was a mixed inflammatory infiltration mainly composed of lymphocytes with a few eosinophils and histiocytes around the vessels (Figure 2B). Immunohistochemical staining revealed that these small vessels were surrounded by CD163 + cells (Figure 2C), CD206+ cells (Figure 2D), MMP9-bearing cells (Figure 2E), and CCL26-producing cells (Figure 2F). The majority of AHLE develops in head and neck lesion (87.1%) (Table 1). From the above findings, our diagnosis was multiple angiolymphoid hyperplasia with eosinophilia showing unusual presentation. We administered intralesional triamcinolone acetonide, and the papules gradually diminished within 1 month. There were no signs of recurrence at the injected site for at least 3 months. Several topical treatments (steroid, tacrolimus, etc.) have been reported for the treatment of ALHE, but the treatment of ALHE is still controversial. Among the previously reported treatment for ALHE, Bito et al reported the effectiveness of suplatast tosilate, which inhibits the production of IL-4 and IL-5 from type 2 helper T (Th2) cells. Since ALHE is recognized as a distinct entity from Kimura's disease, and previous reports suggested a correlation between Kimura disease and Th2 related cytokines and chemokines (IL-4, IL-5, CCL17, and CCL26), these Th2 related factors might correlate with the pathogenesis of ALHE as in Kimura's disease. Indeed, substantial numbers of CCL26-producing cells were detected in the lesional skin of the present case. As previous report suggested, CCL26 could be produced from CD163+ CD206+ M2 macrophages and be a target for eosinophil-related skin disease such as bullous pemphigoid (BP). CD163+ M2 macrophages and CD206+ M2 macrophages are prominent in the perivascular lesion in the dermis of ALHE like BP, suggesting that these M2 macrophages might play a role in the pathogenesis of ALHE.