Complications and outcomes following injection of foreign material into the male external genitalia for augmentation: a single-centre experience and systematic review

Injection of exogenous material into the penis and scrotum has been performed for augmentation purposes. Complications include cosmetic dissatisfaction, penile necrosis and lymphoedema. We report the complications and outcomes from a single centre with an updated systematic review of the literature. A retrospective review of all cases presenting with foreign substance injection into the genitalia, over a 10-year period was performed. Thirty-five patients with a mean (standard deviation (SD); range) age of 36.9 (±9.1; 22–61) years at presentation were included. The mean (SD; range) time between injection and presentation was 7.8 (±5.8; 1 day–20 years) years. The most common injected substance was silicone (n = 16, 45.7%) and liquid paraffin (n = 8, 22.9%). The penile shaft (94.3%) was the most injected site. The most common presentations were cosmetic dissatisfaction (57.1%) and pain and/or swelling (45.7%). Surgery was required in 32 (91.4%) cases. Primary procedures included local excision and primary closure (n = 19, 59.4%), circumcision (n = 5, 15.6%), excision with a split skin graft or a scrotal flap reconstruction (n = 5, 15.6%). Three (8.6%) patients presented with necrosis and required acute debridement. Overall, 18 patients had more than 1 procedure, and 8 patients required 3 or more procedures. A systematic search of the literature identified 887 articles of which 68 studies were included for analysis. The most common substance injected was paraffin (47.7%), followed by silicone (15.8%). The majority of patients (77.9%) presented with pain, swelling or penile deformity. 78.8% of the patients underwent surgical treatment, which included excision and primary closure with or without the use of skin grafts (85.1% of all procedures), the use of flaps (12.3%) and penile amputation (n = 2). Complications of foreign body injection into the male genitalia can be serious resulting in necrosis and autoamputation. Surgical intervention is often required to excise abnormal tissue to manage pain and improve cosmesis.


INTRODUCTION
Genitalia augmentation involving the penis and/or scrotum has been a topical and controversial subject for many years.The definition of a "short" or a "small-sized" penis is unclear and debatable [1].The length and/or the girth of the penis may be augmented surgically and non-surgically, and there has been a rise in non-surgical injections of products into the penis for aesthetic purposes by patients themselves, unregulated injectors, aestheticians, who may or may not be clinicians [2][3][4].
Many injectable products have been used for penile augmentation.Common medical substances used include hyaluronic acid [5], polylactic acid [6], polymethylmethacrylate (PMMA) microspheres [7], autologous fat [8] and liquid silicone [9]; and some non-medical materials used, commonly injected by patients themselves usually without medical advice include, mineral oil (e.g., baby, mechanical and olive oil) [10,11], vaseline [12] and liquid paraffin [13,14].Complications may occur immediately following injections resulting in collection or abscess formation and sepsis, or may occur months and years later as a result of chronic sclerosing inflammation with patients presenting with pain, penile deformity, aesthetic dissatisfaction [13,15,16].Various names of sclerosing inflammation after penile injection have been used interchangeably including, foreign body giant-cell granuloma, sclerosing lipogranuloma, or terms used associated with the product injected, such as paraffinoma, siliconoma and vaselinoma [13,15].
Management depends on the timing and type of presentation and may include, debridement of necrotic tissue, primary excision of the product with primary closure, or reconstruction with skin graft and flaps [13,15].
We previously reported a case series of 5 patients [10], here, we present the largest UK series to date reflecting our experience of managing complications following genitalia injection of foreign material for augmentation.In addition, we provide an update of the literature via a systematic review.

MATERIALS AND METHODS Patients
Following Institutional Review Board (IRB) approval, a retrospective review of all cases presenting with foreign substance injection into the genitalia during a 10-year period between 2010 and 2019 was performed at a single United Kingdom (UK) tertiary centre.Patients were identified through out-patient clinic, operative and histopathological databases.Data collected included patient demographics, type of substance injected, injection site, time between injection and presentation, symptoms at presentation, and management of complications.The study was reported in accordance with the STROBE checklist (Supplementary Table 1) [17].

Systematic review
The PubMed database was searched on August 13, 2022 (Supplementary Material 1).All English articles reporting on complications of genitalia injections for augmentation were included.All titles and abstracts were screened separately by two authors (KHP and ST) initially.Full-text articles of the included abstracts were further screened (KHP and ST).Any disagreements were solved by the two screeners, in cases where no agreement was made, the senior author (HMA) made the final decision.The references of the final list of included studies were also screened for eligibility.

Patients and complications
Overall, 35 patients, mean (SD; range) age of 36.9 (±9.3; 22-61) years presented to our centre over 10 years.The mean (SD; range) follow-up was 18.8 (±25.7;1-120) months.Demographics, site of injection, the substance injected, and clinical presentations are detailed in Table 1.Overall, 29 (82.9%)men were from Europe, of which, 14 (48.3%) were from the UK and 13 (44.8%)were from Eastern Europe.The most commonly used product was silicone (n = 16, 45.7%).The most common site of injection was the penis, whereby 33 (94.3%) patients were injected into this area, of which 11 (31.4%) were also injected into their scrotum.Cosmetic dissatisfaction (n = 20, 57.1%) commonly associated with visible lumps and penile deformity was the most frequent presentation.The second most common presentation was pain and swelling (n = 16, 45.7%).Necrosis at presentation was identified in three (8.8%)patients.The mean (range) time between injection and presentation to our unit was 7.8 (1 day-20 years) years.
During the study period, 61 procedures were performed.Overall, 14 (40%) men had 1 procedure and 1 (2.9%) patient required 5 procedures in order to remove all the products and achieve cosmetic satisfaction (Table 2).The primary procedures (n = 32) are detailed in Table 2.A total of 19 (58.4%) patients underwent excision of the abnormal tissue and injected product with primary closure (Fig. 1).Partial scrotectomy was necessary in 5 of the 19 patients.The three patients who presented with tissue necrosis (penile, n = 2; scrotum, n = 1) underwent acute debridement.All three patients subsequently underwent deferred reconstruction with further excision of any residual product and scrotal flap coverage.Subsequent procedures (n = 29) included further excision of tissue and primary closure (n = 19, 65.5%); excision and split skin graft (n = 3, 10.3%); excision and scrotal flap (n = 3, 10.3%); scrotoplasty (n = 1, 3.5%) (Table 2).Out of the 61 procedures performed in our series, 38 (62.3%) were excision and closures, 7 (11.5%)procedures involved the use of a graft and 4 (6.6%)procedures required a scrotal flap.

Histopathological findings
Within the excised tissue, histopathological findings included deposits of lipid vacuoles embedded in sclerotic stroma with associated foreign body type giant-cell granuloma.Features were Fig. 1 Pre-, intra-, and post-operative images of selected cases.Consent was obtained for the use of photos.1.1a Penoscrotal oedema secondary to silicone injection; 1.1b excision of scrotal silicone; 1.1c 6 weeks post-operative appearance.1.2a Penile oedema secondary to paraffin injection; 1.2b dissection of foreign material.1.3a Penile ulceration and deformity secondary to paraffin injection; 1.3b excision of abnormal penile tissue; 1.3c full-thickness skin graft preparation; 1.3d completion of excision of abnormal penile tissue and reconstruction with skin graft.Patient is now pain-free and sexually active.in keeping with sclerosing lipogranuloma (Fig. 2).No malignancy was detected in any of the samples.

DISCUSSION
Here we report the complications following male genitalia injection of foreign substances for augmentation, and our experience with managing these cases.In our study period, we had 35 patients presenting with complications, and most men were young (mean age, 36.9 years) and sexually active.Visible lumps and penile deformity resulting in cosmetic dissatisfaction occurred in 57.1% of our patients, and pain and swelling were reported in 45.7%.These were the most common presentations identified in our series, and a majority of patients (77.9%) from our systematic review also presented with pain, swelling or penile deformity The most common products used for injection in our patients were silicone (45.7%) and liquid paraffin (22.9%).These two agents were also the most injected products identified in our systematic review.The timing of presentation varied and may be a number of years (up to 20 years) following injection when chronic inflammation and sclerosing lipogranuloma had developed.However, acute complications may occur resulting in necrosis which requires immediate debridement.We encountered three cases of necrosis which required acute surgery.The ultimate aim of treatment is to manage patients' symptoms, prevent progression and provide the best cosmetic and functional outcomes for patients.Reconstructive surgery is associated with risks that patients must be fully informed about.When skin grafts are used, depending on the patient's risk factors (e.g., immunosuppression, smoking, diabetes), there are associated risks and complications when grafting on poorly vascularised beds.
The treatment depends on which area has been injected or involved, patients' symptoms and the patients' expected outcomes.For treatment selection, we recommend MRI penis/ scrotum before embarking on any surgical approach.We excise abnormal or necrotic tissue and try to minimise removing any normal skin.Where there has been excessive skin excision, penile reconstruction is performed with fenestrated split-thickness skin graft or full-thickness skin graft.In severe scrotal lymphoedema, we tend to perform a scrotectomy or "Batman" scrotectomy.The latter involves a "Batman" shape incision and creation of a neoscrotum using the lateral scrotal flaps.This technique was described in a previous publication [79].If there is a loss of penis Table 3. continued in severe cases from autoamputation or necrosis, a phalloplasty at a later stage can be considered following initial debridement.
In our series, the majority were managed with primary excision and closure (62.3%).Our systematic review showed that 85.1% of all procedures were excision with primary closure with or without a graft.In our series, excision with or without grafting consisted of 73.8% of all procedures.
In those who have penile and scrotal involvement, we tend to treat them separately and perform surgery in a staged approach, treating one area first and the other area at a later date.Overall, we had 11 men who were injected into their penis and scrotum and underwent staged procedures.A stepwise surgical approach, by treating the most problematic/symptomatic part first allows wound healing before moving on to other parts of the genitalia.Often wound healing can be problematic in the management of these patients and by following a stepwise approach we can reduce wound complications.In addition, treating the scrotal lymphoedema first may improve the penile lymphoedema and hence avoid further surgery.Downey et al. described the geographical distribution of reported cases and found that the highest incidence of reported cases was in Korea (31.7%), followed by Bulgaria (19.8%) and Hungary (14.3%).Our systematic review demonstrated that the current country with the highest number of reported complications was in Thailand-Myanmar (71.4%), this was due to the fact that the largest case series being from there [29].
The largest series identified from our search consisted of 680 men managed during a 5-year period in Thailand-Myanmar [29].Similar to our study, the majority of patients presented with pain (84%) or swelling (82.5%).Overall, 507 (74.6%) patients required surgical treatment, which included circumcision in 4, and excision with or without graft in 503 men [29].At the time of analysis, our series on complications represents the largest in the UK, and the second largest in the world.Shin et al. also reported a series size similar to ours, consisting of 34 patients [41].They evaluated their surgical repair outcomes during a 6-year period comparing a T-type versus a "new" inverted V-type flap reconstruction technique and found that the latter was associated with lower rates of delayed wound healing (V-type 21.4% vs T-type 100%) and wound infection (V-type 7.1% vs T-type 100%) [41].

Limitations
A limitation of our study is the retrospective design and the possibility of not identifying all patients from the search of our databases.In addition, the reported functional outcomes and patient satisfaction were inconsistently documented in case notes, therefore resulting in only small numbers with inconsistent data which precluded any meaningful analyses.With regard to the systematic review, our search terms may not have captured all relevant studies.A risk of bias assessment of the 68 included reports was not performed.Majority of the included studies were case reports and the reporting of outcomes amongst the included studies was heterogenous which precluded any statistical analyses.

CONCLUSION
Unregulated genitalia injection for aesthetic purposes is becoming popular worldwide.Most products are non-prescribed and are readily available.Patients need to be made aware of the potential complications and the possibility of multiple surgeries to manage any complications.Complications may be severe including tissue necrosis and autoamputation.Referral to a specialist centre for excision of abnormal tissue and reconstruction is recommended to provide the best cosmetic outcomes for this group of young and sexually active men.Apart from penile injections, there are other non-surgical and surgical approaches to augmentation that provide an alternative option for patients.In Schifano et al.'s review, it was highlighted that a multidisciplinary approach is recommended for patients who seek medical advice for penile size concerns.This may require input from surgeons, psychiatrists and psychologists [80].Education and awareness of this practice in addition to targeted regulation of such practices as well as prevention in public health agencies in communities where the practice appears to be more prevalent is paramount to prevent further morbidity.

Fig. 2
Fig. 2 Histopathological slide demonstrating sclerosing lipogranuloma.×4 magnification.Haematoxylin and Eosin stain.There is evidence of foreign body giant-cell reaction around lipid vacuoles and fat necrosis.Courtesy of Dr Aiman Haider, Consultant Urological Histopathologist, University College London Hospital NHS Foundation Trust.London, UK.

Fig. 3
Fig. 3 World map showing geographical distribution of reported cases.

Table 1 .
Patient demographics and clinical details.

Table 2 .
Management of penile injection complications.
a Two patients had a partial scrotectomy.

Table 3 .
Summary of case reports and studies included in the current systematic review.