Precision through innovation: Intralesional radiofrequency with an insulated microneedle probe for angiolymphoid hyperplasia with eosinophilia

INTRODUCTION

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare benign vaso-proliferative disorder characterized by dense eosinophilic inflammatory infiltrate in the dermis or subcutis.¹ It most commonly affects women between 20 and 40 years of age (mean 32 years).^2,3 Clinically, ALHE typically presents as solitary or grouped papules, plaques, or nodules, most often involving the auricle, forehead, and scalp, and less frequently on the trunk, oral mucosa, and genitalia.^3,4Lesions at exposed sites may produce significant cosmetic concern.⁵ ALHE may be asymptomatic or associated with pruritus, pain, or bleeding, but the frequency and prognostic significance of these symptoms remain poorly defined.² Management of ALHE is challenging because of a high recurrence rate. Surgical excision is widely employed, while other modalities including pulsed-dye and carbon-dioxide lasers, oral retinoids, and topical or systemic corticosteroids have been used with variable efficacy.⁵ Intralesional radiofrequency (ILRF) is an emerging treatment option that delivers energy directly into the lesion while sparing the surrounding epidermis. This approach reduces the risk of post-inflammatory pigmentation and scarring and has proven effective in treating conditions such as keloids, hypertrophic scars, syringoma, and hidrocystoma.⁶ Although a small number of ALHE cases treated with ILRF using a cannula have been reported, none have employed any alternative technique of delivering ILRF. To our knowledge, this is the first case of ALHE treated with ILRF using an insulated microneedle radiofrequency (MNRF) needle.

CASE REPORT

A 40-year-old woman presented with a 2½-year history of multiple papulonodular lesions involving the helix and antihelix of the right ear. The lesion began as a single small nodule that progressively enlarged and became lobulated over time, with a few smaller papules developing perilesionally. Symptoms included mild pruritus, intermittent bleeding, and occasional pain; the patient’s main concern was cosmetic disfigurement. There was no history of discharge, fever, systemic symptoms, precipitating trauma, or infection. She had received multiple treatments for variable duration elsewhere, including 6–7 sessions of intralesional corticosteroid injections for presumed keloid, with minimal response. On examination, multiple well-circumscribed, round-to-oval erythematous papules and nodules were present on the superior aspect of the right ear pinna, involving the helix and antihelix. The lesions were firm, non-tender, and adherent to underlying tissue; the largest measured 1.5 × 2.0 cm [Figure 1]. The rest of the mucocutaneous and systemic examination was unremarkable. Histopathology of skin biopsy revealed proliferating blood vessels lined by plump endothelial cells with a dense lymphohistiocytic and eosinophilic infiltrate, consistent with ALHE [Figure 2]. Complete blood count and coagulation profile were within reference ranges. Peripheral eosinophils were 10% (reference range: 1–6%), with an absolute eosinophil count of 386 cells/µL (reference range: 30–350 cells/µL). Correlation of clinical and histopathological features supported the diagnosis of ALHE.

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Figure 1: Clinical photograph of the right ear pinna showing multiple well-circumscribed, round-to-oval erythematous papules and nodules with the largest nodule measuring approximately 1.5 × 2.0 cm involving the superior aspect of the helix and antihelix.

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Figure 2: (a) Low-power view of skin biopsy (Hematoxylin and eosin stain, ×4) showing proliferation of blood vessels (yellow arrows). (b) High-power view (Hematoxylin and eosin stain, ×10) showing proliferation of blood vessels (yellow arrows) along with dense perivascular lymphohistiocytic infiltrate (black arrow) with eosinophils, consistent with angiolymphoid hyperplasia with eosinophilia.

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Given the lesion’s sensitive location, its firm consistency, and the documented failure of prior therapy, there was a clear need for a treatment modality which is more targeted, yet minimally invasive approach was required that could deliver energy precisely within the lesion while minimizing epidermal trauma and cosmetic risk. Therefore, we selected ILRF delivered through a customized insulated MNRF needle assembly specifically designed to enhance control, depth accuracy, and therapeutic efficacy. To address the limitations of conventional probes and ILRF through the traditional cannula-based method which can compromise precision and uniform energy dispersion, we adapted a previously described modification of disposable tips of MNRF probes originally reported for papular scarring.⁶ In our technique, a single microneedle from the MNRF cartridge was carefully removed and seated within the lumen of a 26½-gauge needle. No adhesive was needed, as the internal diameter of the 26½-G needle ensured a secure friction fit that maintained the stability of the assembled insulated needle unit [Figure 3]. Each microneedle within the MNRF cartridge is individually sterile and intended for single use. For every treatment session, a new microneedle was used, even when taken from the same cartridge housing. No microneedle was reused or subjected to resterilization.

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Figure 3: Insulated microneedle and the assembled unit, showing the insulated microneedle securely fitted within a 26½-gauge needle cannula.

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After prepping the area with povidone-iodine and maintaining standard aseptic precautions, local anesthesia was administered by infiltrating 2% plain lignocaine into the lesion. Once adequate anesthesia was achieved, the insulated 26½-G needle assembly was introduced directly to create the epidermal entry point and positioned to target the deepest palpable portion of the lesion. The RF external electrode was then applied to the proximal end of this 26½-G needle assembly, which allowed controlled and focused delivery of radiofrequency (RF) energy while minimizing collateral epidermal injury [Figure 4]. RF energy was delivered for approximately 10 s at four intralesional entry points, guided by tissue resistance and clinical endpoints. A topical antibiotic was applied after each treatment session to minimize the risk of secondary infection. Post-procedure, mild transient erythema was noted. No ulceration, infection, scarring, pigmentary alteration, cartilage damage, or delayed healing was observed. Six treatment sessions were subsequently performed at monthly intervals. A consistent and marked reduction in lesion size was observed after every sitting [Figure 5]. No adjunctive systemic or topical therapies were required throughout the treatment course. At 6-month follow-up, there was no evidence of recurrence, and the patient reported satisfaction with the better therapeutic and cosmetic outcome.

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Figure 4: Intralesional radiofrequency procedure using an insulated microneedle, demonstrating (a) introduction of the insulated 26½-gauge needle assembly to create a single epidermal entry point. (b) Followed by advancement of the needle to the deepest palpable portion of the lesion. (c) The radiofrequency external electrode is applied to the proximal end of the needle assembly, enabling controlled and focused intralesional delivery of radiofrequency energy while minimizing collateral epidermal injury.

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Figure 5: (a-f) Sequential clinical photographs demonstrating treatment response. Progressive reduction in lesion size and thickness is evident after successive intralesional radiofrequency sessions performed at monthly intervals. Near-complete flattening with significant cosmetic improvement is seen after completion of six treatment sessions.

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DISCUSSION

ALHE is a benign yet chronically persistent vascular proliferation that often exhibits therapeutic resistance.^5,7Its precise etiopathogenesis remains uncertain, though it is generally regarded as a reactive endothelial process triggered by local trauma, inflammation, hormonal influences such as elevated estrogen or pregnancy, and occasionally infections like chronic otitis media.^3,7,8 It is synonymous with terms such as pseudo pyogenic granuloma, histiocytoid hemangioma, epithelioid hemangioma, and inflammatory angiomatoid nodules.³ The main differential diagnoses are Kimura disease, pyogenic granuloma, epithelioid hemangioendothelioma, and Kaposi sarcoma.⁸

A wide range of therapeutic modalities has been explored for ALHE, yet outcomes remain inconsistent. Surgical excision is generally regarded as the treatment of choice; however, it carries a recurrence rate of up to 41% and the risk of postoperative scarring, particularly at cosmetically sensitive sites.⁴Laser therapies, including pulsed dye and carbon dioxide lasers, have shown variable efficacy.⁴ In a comprehensive review, Adler et al. reported treatment failure rates (defined as incomplete resolution or recurrence) of 40.8% for excision, 50.0% for pulsed dye laser, and 54.6% for carbon dioxide laser, whereas higher recurrence was observed with argon laser (66.7%), intralesional corticosteroids (79.1%), cryotherapy (80.5%), and systemic or topical corticosteroids (87.8% and 98.2%, respectively).⁹ Other reported therapies, such as systemic retinoids, pentoxifylline, indomethacin, topical tacrolimus, and newer agents including bevacizumab, mepolizumab, and beta-blockers, have demonstrated variable and often transient benefits.^3,7 Despite this broad therapeutic armamentarium, ALHE remains a challenging condition to manage, with high recurrence and unsatisfactory long-term results.³

ILRF operates by increasing the frequency and voltage while reducing the amperage of alternating current, producing ultra-high frequency radio waves that generate heat through tissue resistance and induce controlled thermal destruction of tissue.⁷ ILRF ablation is a simple, cost-effective, and minimally invasive technique widely applied in dermatology. Only a few reports have documented its use in ALHE: Yadav et al. utilized an 18-gauge cannula, Aruna et al. employed a 22-gauge hypodermic needle, and Subhadarshini et al. treated three ALHE cases with similar techniques, all showing satisfactory improvement.^5,10,11

Conventional RF probes are typically stainless-steel electrodes coated with polytetrafluoroethylene (Teflon) and are often limited by bending, breakage, and post-inflammatory hyperpigmentation resulting from epidermal injury.⁶ In contrast, our approach utilizes an insulated MNRF needle that delivers focused energy directly into the lesion while sparing surrounding tissue. The silicone-insulated shaft, with only the distal tip exposed, concentrates RF energy at the lesion core, minimizing collateral damage. Compared with conventional Teflon-coated probes, the MNRF needle-based assembly offers superior durability and electrical efficiency: gold-coated stainless-steel needles enhance conductivity, reduce tip charring, and allow smooth reinsertion with consistent energy transmission. Furthermore, disposable MNRF tips markedly lower per-needle cost, permitting frequent replacement and maintenance of sharp tips. Collectively, these features minimize tissue trauma and reduce the risk of post-inflammatory hyperpigmentation and scarring. While ILRF using MNRF needles has been described previously for papular scars by Nehete and Chandrashekar,⁶ its application in ALHE has not been reported. To the best of our knowledge, this represents the first documented case of ALHE successfully treated with ILRF using an insulated MNRF needle.

CONCLUSION

Our case demonstrates that an alternative approach of ILRF using an insulated MNRF needle is a simple, safe, reliable, minimally invasive, and cost-effective alternative to conventional modalities of treatment.

By overcoming the limitations of traditional insulated electrodes, the MNRF needle-based assembly offers improved safety, energy precision, and less collateral damage to the surrounding tissue. This approach broadens the therapeutic scope of ILRF and represents a valuable addition to the dermatologic surgeon’s armamentarium for managing ALHE and similar lesions. Future studies are needed to identify more effective treatment approaches for ALHE.