Lipogranuloma of the penis is defined as a foreign body reaction to lipids, hydrocarbons (paraffin tumors), silicones, methacrylate, hyaluronic acid, or collagen fillings.1 According to literature reports, some individuals attempt to augment their genitals with injections of illegal liquid paraffin oil.2,3 In recent years, increased reports of complications associated with lipogranuloma have led to a decline in the use of these paraffin oil injections.4,5 Iatrogenic lipogranuloma of the penis is caused by the infiltration of paraffin oil into the penis subcutaneously along the ruptured urethra after urethral trauma. The incidence of this disease is very low, and there are few reports about it at home and abroad, which has led to an insufficient understanding of this disease among urologists. We report here the case of a patient with iatrogenic lipogranuloma of the penis caused by paraffin oil. This study was approved by the Ethics Committee of The Third Affiliated Hospital of Gansu University of Traditional Chinese Medicine (Baiyin, China; ethics approval No. YL-X2-2016-027). The patient was informed of the content and significance of the study and signed an informed consent form.
A 75-year-old male patient was admitted due to “a penile mass found for more than half a month”. More than half a month before admission, the patient inadvertently found multiple subcutaneous penile masses without pain, and the penis became significantly thicker. At that time, the patient did not seek any diagnosis or treatment, but the mass area increased significantly later. The patient had undergone transurethral resection of a bladder tumor in The Third Affiliated Hospital of Gansu University of Traditional Chinese Medicine on March 9, 2017, and the postoperative diagnosis was high-grade urothelial carcinoma. After surgery, pirarubicin hydrochloride was infused into the bladder regularly for chemotherapy. Three months after the operation, the patient developed dysuria and was diagnosed with urethral stricture. On September 13, 2017, direct visual internal urethrotomy was performed in our hospital, and urethral dilation was performed regularly after the operation.
After admission, the patient underwent physical examination, which showed that the penis diameter was significantly enlarged (Figure 1a), but the color was normal. A mass with a diameter of approximately 2 cm was visible at the junction of the penis root and the scrotum (Figure 1b) without ulceration. Diffuse, hard nodules were palpable under the penile skin, without tenderness, and the glans could not be completely exposed. The patient underwent a pathological biopsy of the penile mass. Surgical exploration revealed that the mass was white tissue, tough, and rich in blood supply, presenting a diffuse distribution with surrounding tissues (Figure 1c). Partial tissues were excised for pathological examination, and hematoxylin-eosin (H&E) staining was performed for the diagnosis. The pathological examination results were as follows: the mass was composed of fibrous connective tissue infiltrated by lymphocytes, plasma cells and a small number of mast cells, and cystic cavities of different sizes were observed. A large number of multinucleated giant cells were observed on the wall of the cystic cavity. The clinical history of the patient and the pathological examination results were consistent with a diagnosis of lipogranuloma (Figure 1d and 1e). The pathological diagnosis and pictures were made by JPH, chief physician of the Department of Pathology in The Third Affiliated Hospital of Gansu University of Traditional Chinese Medicine.
Following admission, the patient received ceftriaxone sodium combined with dexamethasone and azithromycin. No significant reduction in penile mass was observed. The patient was discharged from the hospital with an unhealed condition, and he did not receive any treatment after discharge. Four years later, a follow-up examination showed that the mass was gradually healing. As shown in Figure 1f–1h, the patient’s penile mass had significantly relieved after 4 years.
The patient had undergone urethrotomy for urethral stricture 1 month before the mass was noticed, and the surgery may have damaged the urethral mucosa. After surgery, regular urethral dilation was performed. During urethral dilation, liquid paraffin oil was used for urethral lubrication, and the paraffin oil may have penetrated into the penile subcutaneous connective tissue through the deep penile fascia along the damaged urethra. Thus, the paraffin oil entered the penile subcutaneous tissue as a foreign body, causing a tissue reaction and eventually mechanical damage and tissue necrosis, thereby leading to localized encapsulated granulomatous hyperplasia.
At present, urethrotomy is a minimally invasive routine method used by urologists in the treatment of simple urethral stricture.6,7 Due to the high recurrence of urethral stricture, some patients need regular urethral dilation. During urethral dilation, sterile paraffin oil is used as a lubricant to prevent urethral injury caused by the urethral dilator.8 There are two common application methods of paraffin oil as a lubricant in clinical urethral stricture dilation. One method is to spread paraffin oil on the urethral dilator for urethral dilation. The other method is to directly inject sterile paraffin oil into the urethra with a syringe and then apply pressure to the external urethral outlet for 1–2 min before urethral dilation. The latter method can easily cause paraffin oil infiltration of penile subcutaneous connective tissue in patients with urethral injury, resulting in the occurrence of fat granuloma. Therefore, the injection of paraffin oil into the urethra for urethral lubrication in patients with urethral injury should be carefully considered by clinicians.
More recently, Navarrete et al.9 reported a similar case. A 62-year-old male injected oil subcutaneously into his penis 10 years ago, which resulted in significant penile thickening. The diagnosis was confirmed by dermatoscopy combined with puncture biopsy. Because of our lack of experience in diagnosing the disease, the diagnosis of this case was directly made by incision biopsy. As early as 1984, Albers et al.10 also reported the cases of two patients with iatrogenic ureteral lipogranuloma. The authors injected paraffin oil through the ureteral catheter to facilitate the removal of calculi. Most such operations are successful, especially in patients with incarcerated stones. However, these two patients developed postoperative lipogranuloma of the ureter. Therefore, they strongly urged the use of water-soluble lubricants for the lubrication of ureters at that time. Furthermore, Hohaus et al.3 reported the case of a 30-year-old male with penile lipogranuloma caused by subcutaneous injection of paraffin oil who received medical treatment. The subcutaneous granuloma and the skin involved were removed, and the penile skin graft was taken from the prepuce, with a good prognosis.
Improper application of paraffin oil can cause lipogranuloma in the penis and ureter. Therefore, clinicians should avoid intraluminal injection of paraffin oil in patients with urethral injury. Furthermore, tetracaine colloidal slurry is also used in clinical practice as an alternative to paraffin oil for urethral stricture dilation lubrication. The auxiliary ingredient contained in tetracaine colloidal slurry is a kind of skeleton material that can increase the viscosity of the solution and play a role in lubrication.11 Due to its high viscosity, after injection into the urethra, there is no need to apply pressure to promote the mucosal penetration of narcotic drugs, so there is a certain advantage in preventing the lubricant from entering the penile subcutaneous connective tissue. Therefore, this tetracaine colloidal slurry is worth promoting.
In conclusion, urologists should be cautious about the use of paraffin oil during urethral operation, especially in patients with urethral injury, because improper use of paraffin oil in such patients may lead to penile lipogranuloma formation.
ZCZ was responsible for data collection, literature review, and manuscript drafting. TWZ contributed to data collection and follow-up and helped to revise the manuscript. YQX and JPH conceived the study, participated in its design and coordination, and helped to revise the manuscript. All authors read and approved the final manuscript.
All authors declare no competing interests.
This study was supported by the Science and Technology Project of Baiyin City in 2019 (project No. 2019-1-22Y).
1. Alcalde-Alonso M, Velasco-Albendea FJ, Soto-Díaz A, Gómez-Avivar P, Torres-Gómez FJ. Paraffinoma of the penis and scrotum (sclerosing granuloma of the male genitalia). Indian J Dermatol Venereol Leprol 2017;83:75–7.
2. Downey AP, Osman NI, Mangera A, Inman RD, Reid SV, et al. Penile paraffinoma. Eur Urol Focus 2019;5:894–8.
3. Hohaus K, Bley B, Köstler E, Schönlebe J, Wollina U. Mineral oil granuloma of the penis. J Eur Acad Dermatol Venereol 2003;17:585–7.
4. Cohen JL, Keoleian CM, Krull EA. Penile paraffinoma: self-injection with mineral oil. J Am Acad Dermatol 2002;47:S251–3.
5. Nyirády P, Kelemen Z, Kiss A, Bánfi G, Borka K, et al. Treatment and outcome of vaseline-induced sclerosing lipogranuloma of the penis. Urology 2008;71:1132–7.
6. Bullock TL, Brandes SB. Adult anterior urethral strictures: a national practice patterns survey of board certified urologists in the United States. J Urol 2007;177:685–90.
7. Hughes M, Blakely S, Nikolavsky D. Advancements in transurethral management of urethral stricture disease. Curr Opin Urol 2021;31:504–10.
8. Yildirim H, Hennus PM, Wyndaele MI, de Kort LM. Do previous urethral endoscopic procedures and preoperative self-dilatation increase the risk of stricture recurrence after urethroplasty?. Low Urin Tract Symptoms 2022;14:163–9.
9. Navarrete J, Cabrera R, Bunker CB, Agorio C. Dermoscopy of penile sclerosing granuloma. BMJ Case Rep 2021;14:e239846.
10. Albers DD, Hosty TA, Parkhurst JD, Mosca P, Barnes WF. Oil granuloma of the ureter. J Urol 1984;132:114.
11. Ali MS, McLaren CA, Rouholamin E, O'Connor BT. Ankle fractures in the elderly: nonoperative or operative treatment. J Orthop Trauma 1987;1:275–80.