Red nodular melanoma of the penile foreskin: A case report and literature review

Abstract

The penis is an extremely rare primary site for malignant melanomas, and the clinical presentation may vary greatly. We herein present the case of a 71-year-old male patient who presented with a 6-year history of two slow growing, asymptomatic red macules on the penile foreskin. On physical examination, the mobility of the foreskin was good, and there was no metastasis on computed tomography and magnetic resonance imaging. The patient underwent segmental circumcision for treatment and histological diagnosis, and the histological examination revealed a malignant melanoma. As cancer cells were identified at the edge of the tissue specimen and computed tomography-positron emission tomography revealed increased uptake of ¹⁸F-fluorodeoxyglucose in the penis, wider resection and a right sentinel lymph node biopsy were performed; both specimens came back negative. Two years after the surgery, there has been no evidence of locoregional recurrence or distant metastases. The aim of this report is to alert physicians to include melanoma in the differential diagnosis of red-pigmented lesions of the penile foreskin.

Keywords: circumcision; melanoma; penile foreskin; penis.

Figure 1.

Macroscopic appearance of nodular malignant melanoma involving the penile foreskin.

Figure 2.

(A) The histological characteristics of the penile lesion included atypical melanocytic cells proliferating in the dermis and invading the basal cells of the epidermis [hematoxylin and (H&E) staining; magnification, ×400]. (B) Increased uptake of ¹⁸F-fluorodeoxyglucose (arrow) was detected in the penis (standardized uptake value=3.23) on computed tomography-positron emission tomography. (C) A right sentinel lymph node was emphasized by scintigraphy with Tc-99m-phytate (arrow). (D) The histological examination of the sentinel lymph node biopsy revealed that the inguinal lymph nodes maintained a normal structure with some melanin pigment (H&E staining; magnification, ×400).