Pigmented and polypoid tumor of the pubis.

Seborrheic keratosis is a common benign epidermal tumor occurring in patients aged over 50 years. It is located preferentially in the trunk, head and neck. The genital location is rare. We report a case of 59 year-old-men presenting a seborrheic keratosis of the pubis.

INTRODUCTION

Seborrheic keratosis (SK) is a common, benign, epidermal tumor with predominance in adult patients aged over 50 years. It is preferentially located in the trunk, head, and neck. The genital location is rare. We report an original case of a 59‐year‐old man presenting a SK of the pubis.

CASE PRESENTATION

A 59‐year‐old man, with no medical history, presented to our department with a 15‐year history of a gradually enlarged and pigmented tumor of the pubis. Physical examination showed a humped, well‐defined, verrucous lesion measuring 6 cm in diameter with a rough and warty appearance (Figure 1). No ulceration, crusts, or bleeding was noted. Dermoscopy revealed cerebriform convolutions with densely packed exophytic papillary structures, which were separated by black irregular crypts. Black comedo‐like openings, fissures, and hairpin and dotted vessels were present (Figure 2). The lesion was excised. Histological examination revealed papillomatous hyperplasia of the epidermis with hyperpigmentation of the basal membrane. It also showed tunnels and multiple pseudohorn cysts with ortho‐keratotic hyperkeratosis. The dermis was richly inflammatory with no melanocytic cells. There were no koilocytes. The diagnosis of SK was retained.

FIGURE 1

Humped and pigmented tumor of the pubis, measuring 6 cm in diameter

FIGURE 2

Dermoscopic image showing brain‐like appearance with comedo‐like openings (black arrows), hairpin and dotted vessels (white arrows), and fissures (blue arrows)

DISCUSSION

SK is a common, benign, epidermal tumor with predominance in adult patients aged over 50 years. They are preferentially located in the trunk, head, and neck. The genital location is rare and can mimic genital warts. Different clinical and histologic subtypes have been identified (hyperkeratotic type, acanthotic type, reticular/adenoid type, clonal type, irritating type, regressing type, melanoacanthoma, and verrucous SK with keratoacanthoma‐like features). For our patient, the histologic features match more with the hyperkeratotic type in which hyperkeratosis and papillomatosis of the epidermis are pronounced.

The clinical variability of SK raises some diagnostic difficulties. Dermoscopy is the preferred non‐invasive diagnostic method. Most cases of SK exhibit the typical dermoscopic findings of fissures and ridges, hairpin vessels with white halo, comedo‐like openings, and milia‐like cysts. Histopathologically, these dermoscopic characteristics correspond to papillomatous surface of the epidermis, enlarged capillaries of the dermal papillae, pseudohorn cysts in the epidermis opened to the surface of the lesion, and intraepidermal cysts, respectively.

Dermoscopy of genital warts reveals distinctive patterns and vascular features. The pattern, mosaic in a flat lesion, and finger‐like and knob‐like in papillomatous lesions, reflects the life stages of genital warts. The vascular features include hairpin, glomerular, or dotted vessels. Unna nevus is a variant of melanocytic nevus. It corresponds to a papillomatous dermal or compound nevus. Clinically, it presents as a soft polypoid or sessile lesion, usually papillomatous, light to dark brown in color. On dermoscopy, it shows a typical globular pattern composed of numerous round to oval, tan to dark brown globules and can, in some instances, display exophytic papillary structures. Moreover, dermoscopy usually shows, especially at the periphery, the typical “comma‐like” vessels. Sometimes, milia‐like cysts and comedo‐like openings are also detected by dermoscopy. The wobble sign is useful to distinguish Unna nevus from SK, as papillomatous dermal nevi, unlike SK, wobble when the dermoscope is pushed from site to site.

CONCLUSION

Making a definitive diagnosis of SK can be challenging. The dermoscopy facilitates the diagnosis, but histology may be necessary in some cases, especially in pubic location. In the latter, dermoscopy may show papillary structures, which can be seen not only in SK but also in Unna nevus and genital warts.

CONFLICTS OF INTEREST

None.

AUTHOR CONTRIBUTION

RM and SK wrote the manuscript. AM revised the manuscript. BM, HF, and TH contributed to the management of the patient and revised the article. TH critically reviewed the manuscript and gave final approval. All authors have read and approved the final manuscript and agree to take full responsibility for the integrity and accuracy of the work.

ETHICAL APPROVAL

Hereby, I /Rekik Mariem/ consciously assure that for the manuscript/Pigmented and polypoid tumor of the pubis/ the following is fulfilled: This material is the authors’ own original work, which has not been previously published elsewhere. The paper is not currently being considered for publication elsewhere. The paper reflects the authors’ own research and analysis in a truthful and complete manner. The paper properly credits the meaningful contributions of co‐authors and co‐researchers. The results are appropriately placed in the context of prior and existing research. All sources used are properly disclosed (correct citation). Literally copying of text must be indicated as such by using quotation marks and giving proper reference. All authors have been personally and actively involved in substantial work leading to the paper, and will take public responsibility for its content. The violation of the Ethical Statement rules may result in severe consequences. To verify originality, your article may be checked by the originality detection software iThenticate. See also http://www.elsevier.com/editors/plagdetect. I agree with the above statements and declare that this submission follows the policies of Solid State Ionics as outlined in the Guide for Authors and in the Ethical Statement.

CONSENT

Written consent from the patient was obtained to publish this report in accordance with the journal's patient consent policy.