Sir, Congenital melanocytic nevus (CMN) is described as a type of melanocytic lesion that appears at birth or develops during infancy from pre-existent melanocytes.1,2 It is reported to occur in approximately 1% of newborns.1 CMNs commonly affect the trunk, proximal lower limbs, scalp, and neck and are classified according to size. Most of these nevi do not grow >20 cm in size.1,2 CMNs contain a number of conditions, including the spotted grouped pigmented nevi (SGPNs). These were first described by Scholtz3 in 1932 as a form of pigmented nevi consisting of spotted lesions. They were later reclassified by Morishima et al.4 into three types based on the presence of nevus cells either around the hair follicles or around the eccrine glands.4 SGPNs are a rare clinical presentation, and most reported cases are of the nongiant type, i.e., not exceeding 20 cm in diameter.1–[1–5 We report the case of a giant SGPN. A 21-year-old male presented with asymptomatic diffuse hyperpigmentation associated with raised skin lesions affecting the left lower limb. History revealed that these lesions had been present since birth. The lesions were initially small but increased in size proportionately with the patient’s age. There was no history of itching, burning, pain, or color change nor was there a rapid increase in the size of the lesions. On examination, there were multiple grouped hyperpigmented to black follicular papules measuring 5 × 3 mm studded on a background of hyperpigmentation measuring 35 × 20 cm, involving the entire left lower limb extending from the knee to the ankle Figure 1. In addition, a hyperpigmented patch measuring 5 × 4 cm with hypertrichosis was also observed below the chin on the anterolateral aspect of the neck Figure 2. Another similar hyperpigmented patch measuring 7 × 6 cm with hypertrichosis was observed on his lower back Figure 3. Dermoscopic examination revealed a cobblestone and reticular–globular pattern. The differentials considered included CMN, congenital follicular melanocytic nevus, and hair follicle nevus Figure 4.Figure 1: Multiple grouped follicular black papules forming a plaque encircling the left lower limb.Figure 2: Hyperpigmented patch measuring 5 × 4 cm with hypertrichosis below the chin on the anterolateral aspect of the neck.Figure 3: Hyperpigmented patch measuring 7 × 6 cm with hypertrichosis over the lower back.Figure 4: 40× hematoxylin and eosin (H&E) orthokeratotic and acanthotic epidermis showing few nevus cell nests along the basal layer of the epidermis and dermis.A biopsy was taken from the lesion on the left lower limb. Histopathology demonstrated an orthokeratotic and acanthotic epidermis showing a few nevus cell nests along the basal layer of the epidermis. The dermis also showed nevus cell nests. Similar cells, with a few having spindled wavy nuclei, were seen infiltrating the subcutis up to the deeper margin Figures 5 and 6. Our case was diagnosed as a giant SGPN in association with classic CMN. Figs. 5 and 6Figure 5: Cobblestone and reticular–globular pattern on dermoscopy.Figure 6: 10× hematoxylin and eosin (H&E) orthokeratotic and acanthotic epidermis showing few nevus cell nests along the basal layer of the epidermis and dermis.The term SGPN was originally used for nongiant forms of CMN.1 These nevi were classified by Morishima et al. into three types: type I (grouped follicular black papules forming a plaque), type II (aggregated pigmented macules), and type III (freckling over a background of pigmentation).4 Histopathology demonstrates localization of melanocytes around the eccrine glands in type II and type III, whereas perifollicular localization is seen in type I. Types II and III were reclassified as “agminated nevi” and “nevus spilus,” respectively.4 Although the histopathology of all three types differs, clinically all these present predominantly as grouped papular or macular lesions. Owing to its clinical presentation, Sardana et al.3 suggested the term “congenital follicular melanocytic nevus” to be more appropriate than “SGPN.” Our case had features of type I clinically and types I and II groups histopathologically as classified by Morishima et al.4 SGPN with features of both types I and II are not commonly recognized. Type I is a rare condition with infrequent reporting with a mention in only one major textbook.1 The SGPNs are uncommonly reported, probably because of the difficulty in diagnosis. Our case had the clinical distinction of grouped follicular papules with localized area of hypertrichosis and terminal hair. This clinical picture can be easily mistaken for other nevi with a follicular/papular morphology, such as hair follicle nevus, collagenoma, nevus comedonicus, and basaloid follicular hamartoma. However, the presence of aggregated follicular papules with terminal hair in a patient with history of congenital onset is a diagnostic lead in a case of SGPN. In the largest series reported by Morishima et al.,4 there was a consistent finding of follicular localization of nevus cells, with aggregated follicular papules (type 1), as was observed in our patient. The management of giant CMN is still uncertain. Treatment depends on two major factors: cosmetically satisfactory outcomes and monitoring for risk of melanoma development.1 Due to the significant size of the lesion and potential risk of malignant transformation, the patient was educated on the importance of regular follow-up and explained the signs of progression of the lesions.
Dhawan et al. (Thu,) studied this question.