Pigment International

: 2021  |  Volume : 8  |  Issue : 3  |  Page : 190--192

Kissing nevus/divided nevus of the penis: reporting a rare case with dermoscopic findings

Preema Sinha, Afreen Ayub, K. Lekshmipriya, Saikat Bhattacharjee 
 Department of Dermatology, Base Hospital, Lucknow, Uttar Pradesh, India

Correspondence Address:
Dr. Preema Sinha
Department of Dermatology, Base Hospital, Lucknow 226002, Uttar Pradesh

How to cite this article:
Sinha P, Ayub A, Lekshmipriya K, Bhattacharjee S. Kissing nevus/divided nevus of the penis: reporting a rare case with dermoscopic findings.Pigment Int 2021;8:190-192

How to cite this URL:
Sinha P, Ayub A, Lekshmipriya K, Bhattacharjee S. Kissing nevus/divided nevus of the penis: reporting a rare case with dermoscopic findings. Pigment Int [serial online] 2021 [cited 2023 Mar 26 ];8:190-192
Available from: https://www.pigmentinternational.com/text.asp?2021/8/3/190/330885

Full Text

Kissing nevus/divided nevus/split nevus is a rare clinical variant of the congenital melanocytic nevi characteristically observed on adjacent sites of the body at which cleavage occurs during embryogenesis.[1] The first description of a divided nevus was in 1908 on the eyelids, and since then few reports have been published. A kissing nevus appears to be a single lesion when the lids are closed. Other rare sites have been described which include the penis,[1] fingers,[2] and mast cell tumors.[3] Divided nevus of the penis is exceedingly rare, with infrequent mentions in the literature.[4],[5] We discuss one such rare case here along with its dermoscopic features.

A 21-year-old healthy uncircumcised male, with no high-risk sexual behavior presented to the dermatology outpatient department with two asymptomatic darkly pigmented patches on the glans and prepuce for 2 years. There was a history of the lesion increasing in size and becoming darker in color which caused the patient aesthetic and psychologic concerns over the last 6 months. He gave no history of any local trauma, drug intake before the onset of lesions, or risk factors for sexually transmitted infections. No personal or family history of melanoma or other types of skin cancer was present.

Physical examination of the lesion revealed two well-defined hyperpigmented plaques of size 18 × 11 mm and 15 × 12 mm on the right lateral aspect of the prepuce and glans, respectively [Figure 1]. These lesions did not affect the coronal sulcus but were seen on each side of it and overlapped each other like a mirror image when the prepuce was retracted. Inguinal lymph nodes were not palpable. Laboratory tests were within normal limits.{Figure 1}

Dermoscopy of both lesions revealed melanocytic lesions in a compound pattern. Lesion on the prepuce showed a globular pattern with dense symmetrically distributed globules while that on the glans penis showed dots and globules in a cobblestone pattern. No vascular structures were identified [Figure 2] and [Figure 3].{Figure 2}{Figure 3}

Based upon these highly distinctive clinical features and the benign dermoscopic features, a diagnosis of kissing nevus of the penis was reached. The patient was unwilling for a biopsy hence it was not done. Clinical and dermoscopic images were obtained after consent and the patient was counseled thoroughly and put under clinical follow-up with regular evaluations.

The divided nevus was first described on the eyelids in 1908 by Van Michael Paul and the name divided nevus or kissing nevus was given by Fuchs in 1919.[6] The first case on the penis was described by Desruelles in 1998. It has been defined as two adjacent brownish to black pigmented lesions which are mirror image of one another due to split along with the division of the body during embryogenesis. Other types of kissing nevi that have been reported in the literature include nevus spilus of the eyelids, a divided mast cell nevus, and epidermal nevi of the finger.[6]

The kissing nevus of the penis originates from a single melanoblast lesion at the distal edge of the penis that is divided during the separation of the glans from the prepuce in the 11 to 14 weeks of gestation. According to the hypothesis proposed by Desruelles et al. migration of melanoblasts precedes the embryologic separation of the epithelial glandular placode and the epithelial preputial placode; however, Kono et al. suggested that the migration of melanoblasts occurs soon after the embryonic separation of the glans and prepuce.[1],[4] This results in the clinical presentation of divided nevi, which continue to grow independently after separation.[1],[7]

Clinically, they are well-defined oval- to round-shaped pigmented brown to black macules, with a smooth surface presenting as two mirrored lesions, symmetrical to the coronal sulcus. The diagnosis of divided nevus is clinical, and dermoscopy and histopathology are important ancillary tests for the diagnosis and patient follow-up.[6],[8]

On histopathology, most lesions present as intradermal or compound melanocytic nevi.

The differential diagnosis includes melanotic macule, fixed drug eruption, and melanoma mainly in adults. Usually, almost all kissing nevi lesions of the penis are benign melanocytic nevi. Malignant melanoma of the penis is rare, accounting for <2% of primary penile malignancies. Most cases of malignant melanoma of the penis occur in patients in their sixth and seventh decades.

Dermoscopy is useful in the analysis of these pigmented lesions. It helps in long-term follow-up and avoids unnecessary biopsy and surgery.[8] Mendes et al. demonstrated the presence of large globules and compound patterns, formed by a peripheral pigment network and an area with central globules in case of divided nevus of the penis.[9] Dermoscopic findings in most cases that are typical of cutaneous melanoma which is the main differential include: streaks, blue-whitish veil, and an atypical vascular pattern, besides an irregular pigment network. Dermoscopic features of other pigmented lesions of mucosae kept as differentials include the following three patterns (1) a “structureless pattern” predominantly found in vulvar melanosis with a blue hue, (2) a “parallel pattern” often found in clinically typical melanotic macules of the lips and penis, and (3) a “reticular-like pattern” associated with melanosis occurring commonly on the areola or lip.[10]

The therapy if given should focus on functional and aesthetic results. Some authors performed the surgical treatment with satisfactory results in which nevi are excised and the repair is done using a graft from labial mucosa or remaining foreskin.[11] However, for large nevi, there is the concern of aesthetic or functional damage; hence, the use of Nd:YAG laser may be a therapeutic alternative.[6],[11]

In our case, the patient is undergoing six monthly dermatologic follow-ups as an outpatient, with dermoscopy and photographic documentation of the lesion.

We report here a rare case of kissing nevus of the penis that showed an obvious mirror-image symmetry relative to the coronal sulcus with characteristic dermoscopic findings.

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Conflicts of interest

There are no conflicts of interest.


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