Disseminated perforating necrobiosis lipoidica: A case report and literature review

Key Clinical Message Necrobiosis lipoidica is a rare cutaneous granulomatous disease that mainly affects diabetic patients. The perforating type of the disease is an uncommon variant that is resistant to therapy and can be easily identified using dermoscopy. Abstract Perforating necrobiosis lipoidica (NL) is a rare NL variant that primarily affects patients with diabetes mellitus (DM). Dermoscopy helps to differentiate this type of disease. The disseminated form of perforating NL mainly occurs in the setting of DM. Here we present a case of disseminated perforating NL in a 24‐year‐old woman with type 1 DM.


| INTRODUCTION
Necrobiosis lipoidica (NL) is an uncommon chronic granulomatous disease that typically presents as ovoid plaques with a violaceous border and atrophic yellow center. 1 It is typical for NL to occur in the pretibial region, but it can also occur in less typical and rare locations such as upper extremities, face, trunk, and scalp. 1,2Controversy still exists concerning the pathogenesis of the disease; however, microangiopathy has been suggested as the primary cause of altered collagen seen in NL. 2 A deposition of glycoprotein in the blood vessel walls of diabetic patients leads to microangiopathy and abnormal collagen fibrils, all considered end organ damage in diabetic patients. 3he incidence of NL in diabetic patients is 0.3%-1.2%.Perforating NL is an even rarer variant of the disease that was first described by Parra et al in 1977 4 with less than 30 cases reported in the literature.5][6][7][8] However, to the best of our knowledge, only one previous report has described the dermoscopic pattern of perforating NL. 8 Herein, we present a case of disseminated perforating NL in a 25-year-old woman with type 1 diabetes mellitus along with its dermoscopic pattern.Then, we review the literature on disseminated forms of perforating NL.

| CASE REPORT
A 25-year-old woman with type 1 diabetes mellitus was referred to a university-affiliated dermatology clinic with a 2-year history of disseminated cutaneous lesions.She was a known case of diabetes mellitus and hypothyroidism in the past 8 years and was taking insulin and thyroxine.During these years, she had uncontrolled diabetes.The skin lesions first appeared as erythematous patches on her legs (Figure 1A) and gradually spread to other parts of the body including upper extremities and back (Figure 1B-D).Clinically, the lesions consist of well-demarcated yellowbrown atrophic plaques and papules with comedo-like openings and keratinous plugs.
Dermoscopy revealed diffuse structureless yellowishpinkish background and well-focused linear vessels.Additionally, there were comedo-like openings that correspond to perforating degenerated collagen on histopathology.Scattered white structureless areas, follicular plugging, and silvery-white lamellated scales were additional dermoscopic findings (Figure 2A,B).
The biopsy specimen from the right arm showed interstitial granulomatous dermatitis involving total dermis and subcutaneous tissue accompanied by areas of collagen degeneration with sclerosis.These areas were surrounded by a variable lymphohistiocytic infiltrate (Figure 3).
The patient received topical potent corticosteroid for a duration of 1 year along with five separate injections of triamcinolone acetonide administered at monthly intervals.Unfortunately, these treatments did not yield any significant results.As the next step, we commenced a therapeutic trial by prescribing hydroxychloroquine at 400 mg daily for a period of 6 months.However, she did not exhibit any response to this medication and ultimately opted against pursuing further treatment.

| DISCUSSION
Necrobiosis lipoidica is a rare granulomatous and inflammatory cutaneous disorder characterized by collagen degeneration associated with diabetes mellitus. 1linical manifestations of the perforating form include well-demarcated yellow-brown atrophic plaques with comedo-like papules. 2 Dermoscopy is a useful technique helping to identify perforating type of NL due to its ability to show transepidermal elimination of degenerated collagen as comedo-like opening and keratotic plug. 8Most theories on pathogenesis revolve around microvascular damage.Microangiopathic vessel changes seen in diabetic patients could contribute to the development of collagen degeneration and subsequent dermal inflammation. 2,5his altered material causes the expression of keratinocyte receptors for the specific types of collagen and elastin (e.g., collagen IV, V, VI, and 67-kDa elastin receptor) resulting in the transepidermal and transfollicualr perforation of collagen, elastin, necrotic connective tissue, and calcium. 6isseminated perforating NL represents an exceedingly very rare variant of NL.This form was defined as affecting at least the trunk and either the upper or lower, or both extremities. 9To the best of our knowledge, there have been only five previously reported cases of this variant.5][6][7][8] (Table 1).
As shown in Table 1, there were a total of six patients, including our case, with four being female and two being male.The mean age of patients excluding our case, was 56.8 years, which was significantly older than the current case.All patients had lesions on their extremities, and four patients (66.6%) had additional lesions on the chest, back, or abdomen.The histology in all cases showed collagen degeneration or granulomatous dermatitis with transepidermal and/or transfollicualr elimination.
Perforating NL is often resistant to conventional modalities such as topical or intralesional corticosteroids and immunosuppressive agents for stubborn lesions, and its management is a subject of debate. 2,5It is evident that no treatment for NL has been proven effective in large randomized controlled trials (RCTs).However, the first-line treatment is topical or intralesional steroid therapy.In cases where the disease is refractory to treatment, other options include topical photochemotherapy or systemic treatment with TNFα inhibitors, systemic steroids (preferably in nondiabetic patients), pentoxifylline, or hydroxychloroquine. 10Based on our literature review, unlike some localized forms, all cases of disseminated perforating NL including the current case were refractory to treatment.In light of this, dermoscopic examination helps not only to detect the perforating form of the disease but also becomes important from a prognostic point of view.
In conclusion, we present a case of disseminated perforating NL in a 24-year-old woman with type 1 diabetes mellitus.Diagnosis of perforating NL can be achieved through a clinical-pathological correlation.However, dermoscopy provides additional clues for identifying the perforating type by examining the entire lesions and determining the best site for biopsy to observe the transepidermal elimination.

F I G U R E 1
Clinical images.Multiple atrophic plaques involving patient's lower (A) and upper extremities (B,C).Similar lesions on the back (D).

F I G U R E 2
Dermoscopic images.Well-focused linear vessels, comedolike openings, white structureless areas, follicular plugging, and silvery-white lamellated scales on a pinkish-yellowish background.F I G U R E 3 Histopathological images.Interstitial granulomatous dermatitis involving total dermis and subcutaneous tissue accompanied by areas of collagen degeneration with sclerosis.(H&E, ×40, and ×100 [inset]).T A B L E 1 Reported cases of disseminated perforating necrobiosis lipoidica a .