Sub-Saharan African Journal of Medicine

CASE REPORT
Year
: 2018  |  Volume : 5  |  Issue : 4  |  Page : 138--141

Giant Congenital Melanocytic Nevi: Case Report and Review of Literature


Yakubu Abubakar1, Hafsat Rufai Ahmad2, Jamilu Abdullahi Faruk2,  
1 Department of Paediatrics, Ahmadu Bello University/Teaching Hospital, Zaria, Kaduna State, Nigeria
2 Haematology/Oncology Unit, Department of Paediatrics, Ahmadu Bello University/Teaching Hospital, Zaria, Kaduna State, Nigeria

Correspondence Address:
Dr. Yakubu Abubakar
Department of Paediatrics, Ahmadu Bello University/Teaching Hospital, Zaria, Kaduna State
Nigeria

Abstract

Background: Giant congenital melanocytic nevus is defined as a melanocytic lesion present at birth that reaches a diameter of more than 20 cm in adulthood. Its incidence is estimated as below 1:500,000 newborns. These lesions have a major psychosocial impact on the patient and the family because of its unsightly appearance in addition to neurological complications and high risk of malignant transformation into a melanoma. Case: A 6-month-old girl presented with hyperpigmented skin lesions over the back, gluteal regions, perineum, thighs, and scalp since birth with a progressive increase in number and sizes of satellite lesions all over the body. A clinical diagnosis of giant cell melanocytic nevi was made because of the sizes, location, and color of the lesions. Although she was planned to have a thorough neurological assessment due to the number and sizes of the lesions, she was lost to follow-up because of financial constraints and the perception that no medical/surgical intervention could be offered to her. Conclusions: Giant congenital melanocytic nevi are rarely seen or reported. It is however worthy to note that adequate investigation, proper and effective communications between physicians and the parents/patient, and monitoring for neurological complications are essential in ensuring satisfaction in the quality of life of these patients.



How to cite this article:
Abubakar Y, Ahmad HR, Faruk JA. Giant Congenital Melanocytic Nevi: Case Report and Review of Literature.Sub-Saharan Afr J Med 2018;5:138-141


How to cite this URL:
Abubakar Y, Ahmad HR, Faruk JA. Giant Congenital Melanocytic Nevi: Case Report and Review of Literature. Sub-Saharan Afr J Med [serial online] 2018 [cited 2019 Nov 14 ];5:138-141
Available from: http://www.ssajm.org/text.asp?2018/5/4/138/267126


Full Text



 Introduction



Melanocytic nevi are benign proliferations of melanocytes (nevus cells) arranged in nests in the epidermis, dermis, or other tissues. Congenital melanocytic nevi (CMN) are present at birth.[1] Giant congenital melanocytic nevus (GCMN) is defined as melanocytic lesion present at birth that reaches a diameter of more than 20 cm in adulthood.[2] Incidence of CMN is estimated at below 1:20,000 newborns,[2] and seen in 1% to 6% of neonates.[3] It commonly occurs on the posterior trunk and then head or extremities. Congenital nevi are characterized by the presence of nevus cells in the lower reticular dermis; between collagen bundles, surrounding cutaneous appendages, nerves, and vessels in the lower dermis; and occasionally extending to the subcuticular fat.[2] The diagnosis of GCMN is basically clinical.[4] The risk of malignant degeneration (melanoma) and the psychosocial impact on patients because of unsightly appearance often requires surgical excision with reconstruction of the resultant defect.[5],[6]

 Case History



HM, a 6-month-old girl, presented with hyperpigmented skin lesions over the back, gluteal regions, perineum, thighs, and scalp since birth. The increasing number of other smaller satellite lesions on the trunk, extremities, and skull increase in sizes of the initial ones in the preceding 4 weeks made the parents to bring the child for consultation at a secondary health facility. There was no history of convulsion or abnormal body movement. The child had achieved appropriate developmental milestones for age. There was no family history of similar lesions. She had head circumference of 43 cm, weight of 7.2 kg, and height of 65 cm. Neurological examination was essentially normal. An extensive black nevus on the back extending from T12 vertebrate to the gluteal regions [Figure 1]a, right iliac region, right thigh, perineal region [Figure 1]b measuring 31 cm in its largest diameter, and the scalp [Figure 1]c with some multiple satellite nevi on the abdomen, back, scalp, and extremities were seen with diameters ranging from 0.5 to 2 cm. Full blood count, and renal and liver function tests were within normal limits. Electroencephalogram, computed tomography of the brain, and skin biopsy could not be done because of nonavailability of the facilities. The diagnosis of GCMN was made basically on clinical features; however, nevus spilus (speckled lentiginous nevus) and dermatofibroma were differential diagnosis. The parents were counselled on the illness, complications, and the need for neurological evaluation and monitoring but were, however, lost to follow-up because of financial constraint and the perception that the child will not benefit from medical/surgical intervention after 3 months period of follow-up.{Figure 1}

 Discussion



Although most CMN become apparent only months or years after birth,[1] our patient’s lesions were noted at birth. The vast majority are sporadic cases with probable multifactorial inheritance pattern, but GCMN is thought to be caused by spontaneous mutation that may be inherited in some families.[7] Chromosomal rearrangements involving 1p, 12p, and 19p regions had been shown from melanocyte cultures of such lesions.[7]

The incidence of CMN is about less than 1:20,000 newborns,[2] and the “garment-like” GCMN variety is even rarer seen in 1:500,000 newborns.[2] Although some studies show slightly higher prevalence of GCMN in female patients, with ratios ranging from 1.17:1 to 1.46:1,[8] there is, however, no clear sex predilection reported for the development of melanocytic nevi. Several criteria have been used to classify (CMN) based on size. A recent classification categorized CMN as small (<1.5 cm), medium (M1: 1.5–­10, M2: >10-–20 cm), large (L1: >20–30, L2: >30–40 cm), and giant (G1: >40–60, G2: >60 cm).[9] In addition, the number of satellite nevi in the first year of life is categorized into none, 1 to 20, more than 20 to 50, and more than 50 satellites.[9] Our patient was of the L2 category, as the largest lesion extending from the perineal region to T12 vertebrate measured 31 cm. Sites of predilection for small CMN are the lower trunk, upper back, shoulders, chest, and proximal limbs. GCMN occurs most commonly on the posterior trunk but may also appear on the head or extremities. The lesions may be flat, elevated, verrucous, or nodular, and may be of various shades of brown, blue, or black. Our patient had about 30 small black flat lesions all over the trunk, limbs, and the scalp.

The diagnosis of GCMN is basically clinical[4] done by examining for clinical and dermoscopic features. The larger CMN can be diagnosed solely based on their sizes, and for smaller CMN, their presence since birth, surface topography, presence of hair, or globular dermoscopic pattern can assist in diagnosis. Our patient had large lesion (31 cm) that were black, flat with some nodules at the lumbosacral area with no hair except those on the scalp. When biopsied, the histological features of CMN are similar to those found in acquired nevi that arise later in life; however, CMN tend to have greater cellularity with deeper extension of nevus cells into the deep dermis and subcutis, and cells extend along adnexal structures such as hair follicles and around blood vessels and nerves.

Neurological complications such as tethered spinal cord, epilepsy, and hydrocephalous may occur in patients with multiple CMN or a large CMN with >20 satellite lesions. Patients with >20 lesions are five times more likely to have neurocutaneous melanocytosis and become symptomatic.[4] Our patient had about 30 satellite lesions, and by the above criteria she is likely to become symptomatic such as epilepsy, hydrocephalous, and tethered spinal cord syndrome.[4] Neurological evaluation with appropriate imaging such as computed tomography or magnetic resonance imaging is therefore recommended for such patients especially if they develop new symptoms like enuresis and tiptoeing.[4]

Surgical excision is the standard care for GCMN; however, extensive size of the lesions coupled with hypertrophic scarring and keloid formation continues to play a major limiting factor in surgical intervention. The use of hair removal laser may be safe and effective for small nevi; however, there is risk of malignancy developing from a dermal component of the nevus that is not reached by the laser. Repigmentation after laser treatment or superficial curettage have led to proliferative nodules that may or may not be benign.[10]

The goal of surgical treatment is to reduce nevocytic density and prevent malignant transformation, as well as providing good cosmetic appearance.[6]

The risk of melanoma arising within small and medium CMN is <1% over a lifetime and virtually nonexistent before puberty.[3] Cutaneous or extra cutaneous melanoma develops in approximately 5% of patients with a large CMN, with half of this risk occurring in the first few years of life. Melanoma and neurocutaneous melanocytosis are most likely in patients with CMN that have a final size of >40 cm in diameter, numerous satellite nevi, and a truncal location.[3] Although in our patient, the largest lesion measured 31 cm, it could not be said to have reached the final size as the child was just 6 months, hence the possibility of increase in size with growth of the child. The numerous satellite nevi and truncal lesion in our patient suggests high risk factor of likely developing melanoma.

 Conclusion



GCMN are rarely seen or reported. It is, however, noteworthy that adequate investigation, proper and effective communications between physicians and the parents/patient, and monitoring for neurological complications are essential in ensuring satisfaction in the quality of these patients.

Financial support and sponsorship

Nil.

Conflicts on interest

There are no conflicts of interest.

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