A case of Lentigo Maligna in an elderly Filipino manLunardi Bintanjoyo, MDa; Johannes F. Dayrit, MD, FPDSb; Alexander R. Castillo, MD, FPDSb

Introduction: Lentigo maligna (LM) is a form of melanoma in situ (MIS) occurring as a melanocytic lesion mostly on the head and neck of the elderly. It mainly affects Caucasians and is associated with light skin color. The occurrence of LM in Asians is rare. This report highlights the occurrence of lentigo maligna in an elderly Filipino male with Fitzpatrick skin phototype IV.

Case Summary: A 71-year-old Filipino male presented with a 3-year history of solitary asymptomatic brown patch on the right cheek, gradually increasing in size and intensity of pigmentation. Patient worked as warehouse supervisor with little occupational sun exposure, but often had recreational sun exposure due to his fishing hobby. Physical examination showed a 1.5 cm x 1.5 cm ill-defined irregularly-shaped asymmetric brown-to-black patch on the right cheek. Dermoscopy showed rhomboidal structures with asymmetric perifollicular opening and multiple black dots. Histological examination showed focal atrophy of the epidermis, basal cell hyperpigmentation and presence of atypical melanocytes at the dermo-epidermal junction. Some of the atypical melanocytes are also found lining up the follicular infundibulum. Focal pagetoid spread is seen. The dermis reveals solar elastosis, numerous pigment-laden macrophages and a sparse perivascular inflammatory infiltrate of lymphocytes. Diagnosis of lentigo maligna was made. Patient was treated with carbon dioxide laser ablation.

Conclusion: LM is the most frequent type of MIS, developing in individuals older than 40 years and linked to cumulative ultraviolet radiation exposure. LM presents as a patch with shades of dark to tan pigmentation on actinic-damaged skin, most commonly on the cheek. Dermoscopy revealed characteristic rhomboidal structures and asymmetric perifollicular openings. Histopathology showed atrophy of the epidermis, confluent proliferation of atypical melanocytes along the dermoepidermal junction with minimal pagetoid spread, extending to the adnexal structures, and extensive solar elastosis in the dermis. Surgical excision continues to be the treatment of choice for LM. Laser ablation with carbon dioxide has not been a first-line treatment. However it may be beneficial for LM in cosmetically significant locations and owing to its short duration and minimal morbidity in predominantly aging population of LM. LM may develop into LMM in 5% of cases.

Keywords: lentigo maligna, Filipino skin, melanocytic lesions

INTRODUCTION

Lentigo maligna (LM) is a form of melanoma in situ (MIS) occurring on sun-damaged skin.1,2 LM presents as a melanocytic lesion developing mostly on the head and

neck of elderly individuals. It mainly affects Caucasians and are associated with light skin color. LM occurring in Asians is rare.2,3 This report highlights occurrence of Lentigo Maligna in a skin-type IV Filipino male.

CASE REPORT

A 71-year-old Filipino male presented with a 3-year history of solitary nontender nonpruritic brown patch on the right cheek. Gradual increase in size and amount of pigmentation were noted. Past medical history and family medical history were noncontributory. On personal social history, patient worked as warehouse supervisor for 50 years with little occupational sun exposure. However, patient often had recreational sun exposure due to his fishing hobby. Patient previously was a 40-pack-year smoker. Physical examination

showed a 1.5 cm x 1.5 cm ill-defined irregularly-shaped asymmetric brown-to-black patch on the right cheek (Figure 1). Dermoscopy of the lesion shows rhomboidal structures with asymmetric perifollicular opening and peppering (Figure 2).

A 4-mm skin punch biopsy shows focal atrophy of the epidermis, basal cell hyperpigmentation and presence of atypical melanocytes at the dermo-epidermal junction. Some of the atypical melanocytes are also found lining up the infundibulum. Focal pagetoid spread is seen. The dermis reveals solar elastosis, numerous pigment-laden macrophages and a sparse perivascular inflammatory infiltrate of lymphocytes (Figure 3).

Patient was treated with carbon dioxide laser ablation. Two passes of the laser with peak power of 248W, pulse duration of 600μs and repeat time of 10ms were given, followed by one pass with peak power of 261W, pulse duration of 400μs, and repeat time of 20ms.

DISCUSSION

LM is the most frequent histologic type of MIS and also the precursor of Lentigo Maligna Melanoma (LMM).4,5 The incidence of LM, as well those of MIS and LMM, is reported to be rising.2,3,5,6 The annual incidence of LM in Australia is approximately 1.3:100,000. The highest incidence of LM is reported in Hawaii, while the lowest is in Scandinavian region.2-4 LM usually develops in individuals aged older than 40 years, predominantly on the seventh to eighth

Department of Dermatology, Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippinesa Resident b Consultant

Source of funding: noneConflict of interest: none Corresponding author: Lunardi Bintanjoyo, MDEmail: lunardi_bintanjoyo@hotmail.com

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decades. LM is most commonly linked to cumulative ultraviolet radiation (UVR) exposure, but no dose-effect relationship is observed. LM has also been associated with previous sunburn, level of actinic damage, and history of nonmelanoma skin cancer (NMSC).2-4,7 Predominance of LM in Caucasian and association with light skin color2,3 however, are not observed in our patient.

LM presents as a gradually-enlarging ill-defined patch with various shade of black, dark brown, brown and tan pigmentation. It usually arises on the background of actinic-damaged skin of the head and neck, most commonly on the cheek.1-3 Characteristic rhomboidal structures and asymmetric perifollicular openings are seen in dermoscopy.8 These findings are consistent with the features observed in our patient.

Histopathologic examination in cases of LM shows atrophy of the epidermis with confluent proliferation of atypical melanocytes along the dermoepidermal junction, extending to the adnexal structures and with minimal pagetoid spread. The dermis revealed extensive solar elastosis. Extension of atypical melanocytes to the hair follicle is frequently seen and is responsible with high recurrence of LM treated with ablation.1

Surgical excision continues to be the treatment of choice for LM with staged surgical excision and Mohs micrographic surgery providing the lowest recurrence rate.1,9 Cryotherapy and various lasers such as argon, Q-switched Nd:YAG, ruby

Figure 3. Histopathology showing focal atrophy of the epidermis (green arrow), basal cell hyperpigmentation and atypical melanocytes (red arrows) at the dermo-epidermal junction. Focal pagetoid spread is seen (yellow arrow). Some of the atypical melanocytes are also found lining up the infundibulum. The dermis reveals solar elastosis (blue arrow), numerous pigment-laden macrophages and a sparse perivascular inflammatory infiltrate of lymphocytes (H&E, 100x, a; 400x, b-d).

Figure 1. Clinical findings. Solitary 1.5 cm x 1.5 cm ill-defined irregularly-shaped asymmetric brown patch on the right cheek (a), close-up view of the lesion (b)

Figure 2. Dermoscopy. Rhomboidal structures with asymmetric perifollicular opening and multiple black dots (a) close-up view of the lesion (b)

and short-pulsed dye lasers are also used in LM.1 Non-surgical management may be considered due to predominance of LM in aging population.1 Topical medications include imiquimod 5% cream, azelaic acid 20% cream, 5-fluorouracil and tazarotene 0.1% gel.1,10 Laser ablation with carbon dioxide has not been suggested as first-line treatment of LM due to lack of controlled studies and high risk of recurrence. However it

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may be beneficial for LM located in cosmetically significant locations due to its short duration of treatment and minimal morbidity.11

The rate of recurrence of LM ranges from 4-5% for Mohs

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7. Gaudy-Marqueste C, Madjlessi N, Guillot B, Avril MF, Grob JJ. Risk factors in elderly people for lentigo maligna compared with other melanomas: a double case-control study. Arch Dermatol. 2009; 145(4):418-23.

8. Chamberlain A. Cutaneous melanoma: atypical variants and presentations. Aust Fam Physician. 2009; 38(7):476-82.

9. McLeod M, Choudhary S, Giannakakis G, Nouri K. Surgical treatments for lentigo maligna: a review. Dermatol Surg. 2011; 37:1210-28.

10. Chimenti S, Carrozzo AM, Citarella L, De Felice C, Peris K. Treatment of lentigo maligna with tazarotene 1% gel. J Am Acad Dermatol. 2004; 50(1):101-3.

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micrographic surgery and staged surgical excision, 8-20% for standard excision, to 20-100% for other therapeutic modalities. The risk of progression of LM to LMM is estimated at 5%.1

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