Background
Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon, vasoproliferative, idiopathic condition that manifests in adults as isolated or grouped papules, plaques, or nodules in the skin of the head and neck. Most patients present with lesions in the skin of the periauricular region, [1] forehead, or scalp. Rare sites of involvement include the hands, [2] shoulders, breasts, penis, oral mucosa, the scrotum. [3] Extracutaneous sites have also been noted to include the orbit, peripheral arteries, the colon, the mandible, the lacrimal gland, the parotid gland, and throat.
A distinct pathologic entity, ALHE is marked by a proliferation of blood vessels with distinctive large endothelial cells. These blood vessels are accompanied by a characteristic inflammatory infiltrate that includes eosinophils. The lesion is benign but may be persistent and is difficult to eradicate.
While ALHE shows some similarity to Kimura disease, it is generally regarded as a separate entity. [4, 5] While ALHE lesions are superficial, Kimura disease involves deeper tissues such as lymph nodes, salivary glands, and the subcutis. Patients also typically have peripheral blood eosinophilia and elevated serum IgE. However, a 2006 report describes ALHE involving the nail bed and underlying bone. [6] Only one report describes a patient with simultaneous tumors, one consistent with Kimura disease and one consistent with ALHE. [7] Such findings challenge whether or not Kimura disease and ALHE represent a spectrum of the same disease.
Pathophysiology
Although angiolymphoid hyperplasia with eosinophilia (ALHE) may be a benign tumor, numerous factors suggest that it is an unusual reactive process. Approximately half the patients have multifocal lesions that are grouped anatomically. ALHE has occurred following various forms of trauma or infection. Histologically, most cases of ALHE show damaged and/or tortuous arteries and veins at the base of the lesion, suggesting that arteriovenous shunting may play a role in the pathogenesis. Hyperestrogenemia (eg, in pregnancy [8, 9] or with oral contraceptive use) may foster growth. Additionally, the distinctive inflammatory infiltrate in ALHE appears to be an intrinsic (not secondary) component of the lesion. Approximately 20% of patients have blood eosinophilia. However, immunoglobulin E levels are not elevated. [10]
Additionally, three reported cases describe follicular mucinosis and ALHE occurring in the same biopsy specimen. [11] T-cell gene rearrangement was detected in 5 of 7 cases of ALHE in one series, raising the possibility that ALHE or a subset of ALHE may be a low-grade T-cell lymphoma, [12] though T-cell gene rearrangement and monoclonality may be seen in reactive phenomenon. Another recent report of ALHE on the scrotum also demonstrated T-cell clonality. [3] Interestingly, two reports of ALHE occurring in patients with either a subsequent [13] or metasynchronous [14] diagnosis of peripheral T-cell lymphoma pose the question of whether ALHE could be an early form of T-cell lymphoma. It should be stressed that the vast majority of cases are entirely benign.
Etiology
Angiolymphoid hyperplasia with eosinophilia (ALHE) is idiopathic. Whether this condition is a neoplastic or reactive state is uncertain; a reactive cause is favored.
Epidemiology
Frequency
Although frequency is unknown, cases have been reported worldwide. Angiolymphoid hyperplasia with eosinophilia (ALHE) is uncommon but not rare; it may be more common in Japan than in other countries.
Race
ALHE is seen most commonly in Asians, followed by whites. Although less common, blacks can develop ALHE.
Sex
ALHE is slightly more common in females; however, a male predominance has been noted in selected Asian studies.
Age
ALHE presents most commonly in patients aged 20-50 years, with mean onset of 30-33 years. This condition is rare in elderly patients and in the non-Asian pediatric population. It only rarely is seen in children, though its occurrence in a 2-year-old boy on the arm post vaccination [15] and in an 8-month-old Japanese infant [16] have been reported.
Prognosis
Surgical excision is the reported to be the most effective treatment for angiolymphoid hyperplasia with eosinophilia (ALHE). Yet, treatment failure rates as high as 41% are reported for this mode of therapy. Laser approaches are less successful in the management of ALHE, with pulsed-dye laser having the lowest reported failure rate at 50%, followed by carbon dioxide laser at 55%. [17]
ALHE can persist for years, but serious complications do not occur. A few cases of nephropathy have been reported in patients with ALHE; however, the association is not strong. This is in contrast to the related entity, Kimura disease, for which the association with nephrotic syndrome is strong. Of note, although, coexistence of Kimura disease and ALHE in the same patient, along with minimal-change glomerulopathy, has been reported. [18]
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Angiolymphoid hyperplasia with eosinophilia typically exhibits flesh-color to erythematous nodules in the vicinity of the ear.
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Pronounced erythema and nodularity due to angiolymphoid hyperplasia with eosinophilia.
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Histologically, angiolymphoid hyperplasia with eosinophilia is marked by thick-walled blood vessels with protuberant endothelium and a prominent inflammatory infiltrate, which typically includes eosinophils.
