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 Table of Contents  
Year : 2021  |  Volume : 8  |  Issue : 2  |  Page : 112-114

Bathing trunk naevus: a case report with dermoscopic findings in a brown child

Department of Dermatology and Venereology, Vijayanagar Institute of Medical Sciences, Ballari, Karnataka, India

Date of Submission13-Aug-2020
Date of Decision23-Oct-2020
Date of Acceptance10-Feb-2021
Date of Web Publication22-Jul-2021

Correspondence Address:
Sambasiviah Chidambara Murthy
Department of Dermatology and Venereology, Vijayanagar Institute of Medical Sciences, Ballari, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/Pigmentinternational.Pigmentinternational_

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Giant congenital melanocytic naevus is a naevus measuring more than 20 cm in adulthood. Its incidence is 1:20,000 and is more common in girls. Bathing trunk naevus, a specific form of giant congenital melanocytic naevus is even rarer with incidence of 1:500,000. Giant congenital melanocytic naevus usually presents as a brown lesion, with flat or mamillated surface, well-defined borders and hypertrichosis. Dermoscopic examination of melanocytic naevi shows brown-blackish background, globules, reticular network and vascular structures. Although giant congenital melanocytic naevus is often diagnosed clinically, dermoscopy aids in detecting early changes of complications such as malignant melanoma. We report a case of bathing trunk naevus with multiple satellite lesions in a brown child with dermoscopic findings.

Keywords: Congenital, dermoscopy, giant, melanocytic, naevus

How to cite this article:
Shankar M, Murthy SC. Bathing trunk naevus: a case report with dermoscopic findings in a brown child. Pigment Int 2021;8:112-4

How to cite this URL:
Shankar M, Murthy SC. Bathing trunk naevus: a case report with dermoscopic findings in a brown child. Pigment Int [serial online] 2021 [cited 2022 Jun 25];8:112-4. Available from: https://www.pigmentinternational.com/text.asp?2021/8/2/112/322065

  Introduction Top

Giant congenital melanocytic naevi (GCMN) are rare, disfiguring lesions which may result in significant psychological distress to the parents and require a thorough counselling by the treating dermatologist. It is important to recognize GCMN for its associated central nervous system involvement and development of complications such as malignant melanoma and neurocutaneous melanosis.[1] Bathing trunk naevus may be associated with several other conditions such as neurocutaneous melanosis, diffuse lipomatosis, von Recklinghausen disease, structural brain malformations, vitiligo, hypertrophy of skull bones and skeletal asymmetry.[2] We report an occurrence of bathing trunk naevus in a young child with its dermoscopic findings.

  Case report Top

A 5-year-old girl born out of a consanguineous marriage presented with asymptomatic, multiple, large, blackish skin lesions covered with thick, black, long hairs involving the entire lower three-fourths of the trunk up to the knees, encircling the entire area circumferentially, since birth. Proportionate increase in size without systemic involvement was seen. Her past, antenatal and family history were unremarkable. Her general condition and vitals were normal.

Cutaneous examination revealed a large, black, thick plaque measuring 43 × 51 cm covering the entire lower three-fourths of the trunk, extending up to the knees, encircling the trunk circumferentially [Figure 1]. The plaque was covered with thick, black terminal hairs, measuring 3 to 6 cm in length, more marked over the thighs. Satellite lesions were present over scalp, face, chest, upper back, right forearm, left arm and left leg with hypertrichosis [Figure 2]. Mucosae, hair, nails, palms and soles were normal. Ophthalmic and systemic examinations were normal.
Figure 1 Giant hairy melanocytic naevus involving trunk up to lower thighs.

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Figure 2 Satellite lesions over chest and upper limbs.

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Her routine haematological, biochemical and urine investigations were normal except for anaemia. X-ray and computed tomography scan of the lumbosacral spines were normal. On dermoscopic examination (DermLite 3; 3Gen, Inc., 31521 Rancho Viejo Road, Suite 104 San Juan Capistrano, CA, USA), there was brownish background with loss of normal reticular network, bluish globular structures, cobblestone-like globules, hypertrichosis and perifollicular scaling with hypopigmentation [Figure 3].
Figure 3 Dermoscopic examination showing brownish background, bluish globular structures (black arrow), cobblestone-like globules (white arrow) and perifollicular scaling with hypopigmentation (DermLite 3, 10×, polarized view).

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  Discussion Top

A melanocytic naevus is an abnormal collection of melanocytes of neuroectodermal origin in an ectopic location. Melanocytic naevi have been generally divided into congenital melanocytic naevi (CMN) which are present at birth and acquired naevi which appear postnatally. GCMN are always present at birth; however, their extent may not be totally visible because of variable degrees of pigmentation at birth, which may increase over time. Consequently, some congenital naevi that are underappreciated at birth may be better visualized within the first 2 years of life and are referred to as tardive naevi.[1]

CMN can be divided into three classes according to their largest diameter in adulthood: small (<1.5 cm); medium (from 1.5–19.9 cm) and large (or giant: ≥20 cm).[3] The GCMN would be further subdivided into three categories: G1 (21–30 cm), G2 (31–40 cm) and G3 (>40 cm).[3]

GCMN are a CMN measuring 20 cm or greater in diameter in adults or predicted to reach 20 cm in diameter by adulthood. This number translates to an estimated diameter of 9 cm on an infant’s head or 6 cm on an infant’s body.[1],[3] GCMN have many synonyms varying with anatomical location, including bathing trunk naevus, vest-like naevus, garment naevus, vest with collar naevus, shoulder stole naevus and cape-like naevus.[1]

The incidence of GCMN is estimated at below 1:20,000 newborns. The variety “garment-like” of GCMN is even rarer, 1:500,000.[3],[4] Histological features include the presence of naevus cells within the lower two-thirds of the dermis and within the subcutaneous tissue, extending between collagen bundles of the reticular dermis as single cells or cords of cells. Naevus cells can also be seen in and around sebaceous glands, hair follicles, eccrine and apocrine sweat glands, blood vessel walls and nerves. GCMN can have naevus cells that extend beyond the subcutaneous tissue and into the fascia or muscle.[1]

GCMN most often occur on the trunk, followed by the extremities and the head and neck presenting as a brownish lesion with well-defined borders and hypertrichosis. In newborns it may have a lighter colouration with few or no hair follicles, occurring as a macule or an elevated lesion. The surface of the nevus may be papular, roughed, warty or cerebriform.[3] The clinical presentation often changes with age; a hairless, pale brown, flat lesion at birth may evolve to have hyperpigmentation and colour variegation, hypertrichosis, erosions or ulcerations, a verrucous texture, and nodularity representing neurotization of the lesion.[1] GCMN have solitary or multiple satellite naevi associated with them dispersed over the trunk, extremities or head and neck. The differential diagnosis includes naevus sebaceous, epidermal naevus, capillary malformations and macular stains.[1]

Dermoscopy is a more useful tool for evaluating small to medium CMN compared to GCMN because of presence of naevus cells in deeper dermis. Most giant naevi show a brownish homogeneous background with darker pigmentation islands. It may also show light brown diffuse pigmentation, the dark brown/black diffuse pigmentation, the variegated diffuse pigmentation and the dark brown/black globular types.[5] Braun et al.[6] found globular architecture arranged in a “cobblestone-like” pattern in 73% of lesions; whereas Changchien et al.[7] found in only 8% of lesions. Other dermoscopic findings include target globules, hypertrichosis, perifollicular hypo- or hyperpigmentation, pseudomilia and vascular structures.[3] Most of the dermoscopic features seen in our case were similar to western literature except for perifollicular scaling and cobblestone-like globules which are less commonly reported.

Complications of GCMN include ulceration, psychosocial dysfunction, melanoma, extracutaneous melanocyte deposits, rarely rhabdomyosarcoma, liposarcoma and malignant peripheral nerve sheath tumour. Leptomeningeal involvement may present with seizures and other clinical findings associated with symptomatic neurocutaneous melanosis.[4]

Treatment may include surgical and nonsurgical procedures with psychological intervention. Various procedures used in partial removal of GCMN are dermabrasion, skin curettage, tangential excision (shave excision), chemical peels and laser treatment which mainly have cosmetic purposes, since only the most superficial cells of the lesion are removed.

Giant bathing trunk naevus is a rare hamartomatous malformation. Early recognition and frequent follow-up is important due to the associated complications. Dermoscopy can be utilized for the follow-up and detection of early changes of malignant transformation. Malignant melanoma shows pseudopods, radial streaming and grey-blue veils.[6] Although, the dermoscopic findings in GCMN are almost comparable to the western population, further reports in our population, need to be awaited.


Authors thank Dr Balachandra S. Ankad, Bagalkot, India, for his valuable opinion on dermoscopic images.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Arneja J, Gosain A. Giant congenital melanocytic nevi. Plast Reconstr Surg 2007;120:26e-40e.  Back to cited text no. 1
Bhagwat PV, Tophakhane RS, Shashikumar BM, Noronha TM, Naidu V. Giant congenital melanocytic nevus (bathing trunk nevus) associated with lipoma and neurofibroma: report of two cases. Indian J Dermatol Venereol Leprol 2009;75:495-8.  Back to cited text no. 2
[PUBMED]  [Full text]  
Viana AC, Gontijo B, Bittencourt FV. Giant congenital melanocytic nevus. An Bras Dermatol 2013;88:863-78.  Back to cited text no. 3
Sasmaz S, Celik S, Ciralik H, Arican O, Gumusalan Y. A case of bathing trunk nevus studded with neurofibroma-like papules. Clin Dysmorphol 2005;14:41-3.  Back to cited text no. 4
Ingordo V, Iannazzone SS, Cusano F, Naldi L. Dermoscopic features of congenital melanocytic nevus and Becker nevus in an adult male population: an analysis with a 10-fold magnification. Dermatology 2006;212:354-60.  Back to cited text no. 5
Braun RP, Calza AM, Krischer J, Saurat JH. The use of digital dermoscopy for the follow-up of congenital nevi: a pilot study. Pediatr Dermatol 2001;18:277-81.  Back to cited text no. 6
Changchien L, Dusza SW, Agero AL et al. Age- and site-specific variation in the dermoscopic patterns of congenital melanocytic nevi: an aid to accurate classification and assessment of melanocytic nevi. Arch Dermatol 2007;143:1007-14.  Back to cited text no. 7


  [Figure 1], [Figure 2], [Figure 3]


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