A case of complication after a degloving operation of melanoma of the penis—repairing urethrocutaneous fistula with a pedicled gracilis flap
KeywordsMelanoma Sentinel Lymph Node Wide Excision Gracilis Muscle Scrotal Skin
Melanoma of the penis is a rare clinical condition. In this case report, our patient had a wide excision for melanoma of the penile skin. After the operation, he developed a urethrocutaneous fistula at the bulbar urethra. The defect was then repaired successfully with a pedicled gracilis flap. The surgical treatment of melanoma of the penis and various reconstructive options for the iatrogenic urethrocutaneous fistula will be discussed.
The skin graft was healthy on the first few days after operation. The urinary catheter was removed on post-operation day 6, but a urethrocutaneous fistula was noted at the region of the bulbar urethra (Fig. 3). The histological examination confirmed the diagnosis of melanoma for all subdermal nodules; the maximum tumour thickness was 13 mm. Both radial and deep resection margins were clear. The sentinel lymph node at the left groin showed metastatic melanoma. Repair of the urethrocutaneous fistula and left groin dissection were therefore performed.
Melanoma of the penis is a rare clinical condition which has been presented previously only in case reports and short series [1, 2, 3, 4]. The mainstay of treatment is surgical. For lesions at the glans or urethra, penectomy is usually required for disease control. For lesions arising from the penile skin, the extent of operation should be judged by the tumour thickness. In the largest series to date, Sánchez-Ortiz et al. found that wide excision without penectomy can provide effective local control for low-stage (i.e. T1, T2) penile melanoma. On the other hand, for thick tumour (i.e. T3, T4), there is still a lack of evidence on the optimal surgical treatment for local control . In our case, as the glans and urethra were not involved and there was no deep involvement of the tumour, wide excision of penile skin was performed for local control.
After the degloving operation of the penis, the structures left behind were the corpora cavernosa and the corpus spongiosum. The penile urethra, particularly the bulbar part, is situated superficially in the corpus spongiosum. The bulbar urethra is therefore the most vulnerable part of the penile urethra. In our case, we postulated that the development of urethrocutaneous fistula is due to the cutting through of stitches at this region. After the excision of the penile and scrotal skin, the residual scrotal skin was sutured to the corpus spongiosum to assist wound closure. As the corpus spongiosum is not a strong structure that can hold stitches firmly, together with the pulling force conferred by the erection of penis, the stitches placed at this region cut through easily. This caused the injury to the underlying bulbar urethra and the subsequent fistula formation. To avoid this complication, a tension-less wound closure should be adopted at this region.
In conclusion, melanoma of the penis is a rare condition. Surgery is the mainstay of treatment. During a degloving operation of the penis, a tension-less closure should be provided at the region of the bulbar urethra to avoid urethral injury. The development of urethrocutaneous fistula in the setting of a denuded penis is a challenge in reconstructive surgery. The pedicled gracilis flap is a feasible reconstructive option which can successfully repair the fistula and achieve a good aesthetic result.
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