Two Adult Cases of Perineal Lipomas: Accessory Scrotum?

By Serkan Akan, Umut Arslan, Ayhan Verit

Affiliations

1. Department of Urology, University of Health Sciences, Fatih Sultan Mehmet Research and Training Hospital, Istanbul, Turkiye

ABSTRACT
A perineal location of a lipoma is uncommon and associated with some poorly described clinical features. Congenital perineal lipomas are known to be associated with an accessory scrotum in >80% of cases. Non-congenital, adult-onset perineal lipoma cases are very rare. Herein, we report two adult patients, aged 48 and 62 years old, who presented with accessory scrota and their histopathology revealed perineal lipomas. Patient management was successfully achieved through the total removal of the supernumerary scrota and perineal adipose tissue masses. No concurrent developmental anomalies or other complications linked to this condition were identified. These presented cases show the prognosis of adult-onset perineal lipomas.

Key Words: Surgery, Accessory scrotum, Perineal lipoma.

INTRODUCTION

A perineal location of a lipoma is uncommon and associated with some poorly described clinical features.¹ It is benign and can be demonstrated by ultrasonography (USG) or computed tomography (CT). Congenital perineal lipomas are known to be associated with an accessory scrotum in >80% of cases. Non- congenital, adult-onset perineal lipoma cases are very rare.² An accessory scrotum is an additional scrotal structure located in the perineum, alongside the anatomically typical scrotum, penis, and testes. Perineal lipomas are known to be associated with an accessory scrotum in >80% of cases. Herein, we report two adult patients who presented with accessory scrota and their histopathology revealed perineal lipomas.

CASE 1:

A 48-year male patient was admitted to the clinic suffering from a soft mass in the perineal region, which was noticed three years ago and had grown over time.

On physical examination, a soft accessory scrotal mass extend- ing to the right lateral aspect of the native scrotum, not associated with the testes, was palpated. No other genitourinary abnormalities or congenital malformations were detected in the circumcised patient. The CT scan reported a 10 × 8 cm mass, extending from the skin with a density similar to adipose tissue, favouring lipoma. The mass was excised totally. Postoperative histological examination showed mature fat cells (Figure 1).

CASE 2:

A 62-year male patient presented with a soft mass in his perineum which was noticed one year ago and had grown over time.

On physical examination, a soft accessory scrotal mass was palpated in the perineal region just caudal to the scrotum. The mass was unrelated to the testes and showed a wrinkled skin area and some hair in the centre. On USG, a 4 × 3 cm mass with adipose tissue echogenicity was evaluated in the favour of lipoma. The histological diagnosis revealed a lipoma with accessory scrotum (Figure 2).

DISCUSSION

Congenital perineal lipomas are rare benign tumours that can be seen in both male and female foetuses. In the literature, approximately 50 cases of congenital perineal lipomas have been reported to date and more than 80% of them presented with other congenital anomalies.³ Accessory scrotum is defined as additional scrotal tissue in addition to a normally developed scrotum; however, an accessory scrotum does not contain testes and always arises posterior to the normally located scrotum. Histologic differences between scrotal and non-scrotal skin include smooth muscle cells under the scrotal dermis; there are no other differentiating characteristics.⁴

From the embryology point of view, development of the external genitalia begins in the fifth week of gestation with the appearance of labioscrotal swellings lateral to the cloacal membrane. The labioscrotal swellings fuse and become the scrotum, and the midline forms the scrotal raphe. Dihydrotestosterone converted from testosterone by 5α-reductase is essential for the development of the scrotum during the early stages of gestation. Non- congenital, adult-onset perineal lipomas are very rare. They can mimic various malignancies with respect to age at presentation, rapid growth, and proximity to the urogenital region. Scrotal wall masses can be differentiated by considering various conditions, including neoplastic lesions such as fibrosarcoma, rhabdomyosarcoma, lymphangioma, and lipoma, as well as congenital anomalies such as sebaceous cysts.⁵ These can be diagnosed by physical examination and USG or CT. The outcome of the perineal lipomas after surgical excision is usually good.

Figure 1: Soft scrotal mass in a 48-year male. (A) Perineal Lipoma before surgery. (B) CT scan of the lipoma. (C) The excised surgical specimen of the perineal lipoma.

Figure 2: Presentation of an accessory scrotum associated with a perineal lipoma in a 62-year. (A) Soft accessory scrotal mass. (B) Ultrasonography image of the scrotal mass.

Generally, the subcutaneous swelling due to the perineal lipoma induces an accessory scrotum or accessory labial fold. In our cases, as with all reported instances, the accessory scrotum did not contain a testicle and consistently appeared posterior to the normally positioned scrotum. The aetiology of the accessory scrotum is poorly defined, as it commonly occurs without any concurrent anomalies.⁶ Small pedunculated lipomas did not influence functional outcomes in the literature, but in patients with large lipomas, the functional outcome was affected.⁷ In our first case, it was noticed as a palpable soft mass three years ago and grew up to 10 cm over time. Due to its size, it caused cosmetic discomfort and pain during sexual intercourse.

In addition, histopathologic confirmation was recommended to exclude malignancy on CT scans. In the second case, it grew up to 4 cm in one year and did not cause any symptoms.

Both cases were effectively managed through the full excision of accessory scrota and associated perineal lipomas. In most instances involving large perineal lipomas, resection of the perineal skin is also performed.² In the first case, skin resection was performed because the mass was very large. However, in our second case, we did not find it necessary. The histological diagnoses were perineal lipomas with accessory scrota. No concurrent congenital abnormalities or other complications associated with this anomaly were identified. These presented cases show the prognosis of adult-onset perineal lipomas.

Adult-onset perineal lipomas are quite rare and have benign characteristics. They should be included in the differential diagnosis when a perineal mass is encountered around the scrotum. Surgical treatment is a straightforward procedure and adequate for the treatment. The prognosis is excellent.

PATIENTS’  CONSENT:
Written informed consent was obtained from the patients for the publication of this case report and any accompanying images.

COMPETING  INTEREST:                                       
The  authors  declared  no  conflict  of  interest.

AUTHORS’  CONTRIBUTION:
SA:  Conception  and  design  of  the  study.
UA, AV: Collected the data, drafted, and revised the manuscript.
All authors approved the final version of the manuscript to be published.

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