RESEARCH LETTER

A Small Series of Large Congenital Nevi: Clinical and Dermoscopic Follow-up

Christina STEFANAKI^1* and Alexander STRATIGOS¹

¹First Dermatology Clinic, Andreas Sygros University Skin Hospital, Athens, Greece. ^*Email: cstefana@otenet.gr

 

 

Dear Editor,

Melanoma in large congenital nevi (CMN) originating from the deep dermis or subcutis, presenting as a nodule or a lump, is difficult to detect dermoscopically (1). However, although large CMN display multiple islands of colour and irregular topography, each “island” within the large CMN tends to be fairly organized and homogeneous in its dermoscopic appearance (2). Following up large CMN dermoscopically is very challenging but can be useful, particularly if combined with good clinical follow-up and palpation.

We followed up clinically and dermoscopically 6 children with large CMN attending our clinic for up to 13 years. The size of the nevus (APS) was estimated according to the classification system by Krengel et al (3). Clinical characteristics were recorded and pictures were taken. The whole nevus was examined by sliding the camera of a digital dermatoscope on its surface and pictures were taken from areas of interest. All children were followed up yearly, unless an alarming change justified an earlier visit. At each visit, clinical and dermoscopic changes were recorded.

Four large and two giant CMN were included in the study, and all were asymmetric and irregularly coloured and shaped. None of the children underwent surgery. Only one large nodule from the upper back was excised from patient 5 with a giant nevus for cosmetic reasons and the pathology revealed neurotized configuration. No melanoma was detected in our cohort.

Patient demographics and nevi clinical and dermoscopic characteristics and changes are presented in Table I.

Table I. Clinical and dermoscopic characteristics of large and giant CMN and changes

	Age	Sex	Location	APS	Nodularity	Nodules	Hair	Satellites	Derm type	AN	HG/ TG	Blo	Milia	Per hyp	SFH	V	BWV	Years	C	nod	Hair	derN	Milia	MA	LA	H
1	6 m	F	L arm	20–30	2	1	2	0	glob	Y	Y	Y	N	Y	N	N	N	13	d	Y	Y	Y	Y	N	N	Y
2	1	M	Abdomen – thighs-genitalia	40–60	0	0	0	20–50	glob	N	Y	Y	N	N	N	N	N	7	l	Y	N	Y	N	Y	N	N
3	5	M	Buttocks-genitalia	30–40	1	1	0	0	hom	N	Y	Y	N	Y	N	N	Y	9	l	N	N	Y	N	N	N	N
4	8	M	R thigh-shin	20–30	0	0	2	0	hom	N	Y	Y	N	Y	Y	N	N	12	l	N	Y	N	N	N	N	N
5	7	M	Back- chest-upper arm-scalp	>60	0	1	2	20–50	glob	N	Y	Y	N	N	N	N	N	6	l	N	Y	N	N	N	Y	Y
6	6 m	M	R hand and palm	20–30	1	0	2	0	glob	N	N	N	N	N	Y	N	N	10	0	Y	Y	N	Y	N	N	Y
AN:atypical network; APS:adult projected size; blo:blotches; BWV:blue white veil; C:color; d:darker; derm type:dermoscopic type; derN:dermal nodules; H:homogenous dermoscopic picture; HG/TG:haloed globules, target globules; l:lighter; LA:less atypical; MA:more atypical; nod:nodularity; per hyp:perifollicular hypopigmentation; SFH:skin furrow hypopigmentation; V:vessels.

It is a common belief that CMN and particularly the large ones may develop any type of change through the years, hypertrichosis, nodularity, homogenous or heterogenous lightening or darkening, but those changes have not been recorded systematically. In our study, a gradual and proportional increase in size with advancing age was observed in all cases, as expected, and the commonest clinical change was the reduction in colour (4/6) (Fig. 1) compatible with the observation in previous studies that CMN commonly become lighter and regress over time (4). Large CMN in our study commonly demonstrated a more nodular-mamillated surface (3/6), but most importantly an increased and excessive hairiness, which was noted in four patients and raised serious cosmetic concerns. Three children developed benign dermal nodules on follow-up, which appeared dermoscopically as areas of focal hypopigmentation and 2 nevi demonstrated milia-like cysts dermoscopically, possibly related to the nevus evolution. Other investigators not focusing on children and adolescents with medium and large CMN and after a short 6 month follow-up period found only a symmetric enlargement without architectural changes (5).

Fig. 1. A giant CMN on the upper back of a child. A soft, large nodule on the upper part. 2: the same giant nevus after 10 years. The colour is lighter and the nodule has been removed surgically. 5: a dermoscopic island of the nevus – homogenous appearance, blotches and blue/white colour. 6: the same dermoscopic island with the basic features remaining unchanged but less atypical.

Increased atypia, defined as an increase in variegation of colour, or development of large and asymmetric globules or pigment network asymmetry and thickening was observed only in one child, whereas reduced atypia was observed in another child. Large CMN commonly demonstrate atypical and alarming features. On the other hand, spontaneous lightening and flattening of those aspects of CMN that appeared atypical towards a more benign homogeneous appearance has been described before in a small number of medium and large CMN with a long follow-up (6). One would expect melanoma originating from the deep dermis in large CMN not to display any particular dermoscopic features; however, a blue/white veil over the palpable nodule could help with detection.

The reported absolute risk of melanoma in large CMN is estimated between 1.25% and 2.9% and the risk increases with the size of the nevus, being highest in giant >60 cm CMN, with a peak before puberty (1). Prophylactic excision of large CMN poses several difficulties and does not eliminate the risk, given that central nervous system melanomas may develop and this correlates with the number of CMN (1). None of our patients developed a melanoma during the follow-up period.

Although our series includes a small number of patients, the long follow-up period including dermoscopic characteristics increases its strength.

REFERENCES

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