Successful combined treatment of Buschke–Lowenstein tumor in anal canal with electroresection, photodynamic therapy and topical 5% imiquimod

Sir,

Buschke–Lowenstein tumor was first described as an invasive and exophytic lesion on the penis in 1925.¹ During the past decades, Buschke-Lowenstein tumor on perineum, anus, and rectum have been reported. However, Buschke–Lowenstein tumor in anal canal has rarely been described. Herein we report a case of Buschke-Lowenstein tumor in anal canal treated with combination of electroresection, laser-mediated photodynamic therapy, and topical 5% imiquimod cream. The lesions had resolved within 4 months of treatment. During the next 8-year follow-up, the patient remained symptom-free without any other complications.

A 24-year-old female visited our out-patient clinic 8 years ago, with a complaint of newly emerging giant warts located in anal canal and recurrent perianal lesions for 6 months. She had a history of anal sex with a male who had multiple sex partners. She had undergone 4 sessions of laser resection previously for her recurrent anogenital warts. Anal speculum examination revealed a bulky cauliflower-like condylomatous mass blocking the anal canal. Complete blood counts, liver and renal function tests were normal. Cellular immunity, assessed by the percentages of CD4+ and CD8+ T cells, CD19+ B cells and natural killer cells in blood, was normal.

Based on the history and clinical features, patient was diagnosed to have Buschke-Lowenstein tumor in anal canal . We resected the giant cauliflower-like lesion by electroresection under epidural anesthesia. The lesion was about 5 cm in diameter and was resected with a 5 mm healthy margin. [Figure 1].

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Figure 1:

Bulky condylomatous lesion about 5 cm in diameter

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Histopathological examination of the mass in the anal canal showed papillary proliferation with extensive acanthosis, parakeratosis, and vacuolization [Figure 2a]. With the positive immunohistochemical staining by in situ hybridization of human papillomavirus antigen (HPV-Ag), the giant lesion was confirmed to be infected by HPV [Figure 2b]. The lesion had no apparent features of malignant tumor or transformation.

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Figure 2a:

Papillary proliferation with obvious vacuolization (H and E, ×100)

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Figure 2b:

Human papilloma virus antigen staining showing positive expression in koilocytes (H and E×100)

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The wound healed 3 weeks postoperatively. However, during the following weekly visits, 4 times of recurrences were recorded on week 4.5, 5.5, 8.5, and 12.6 in the anal canal. We performed electroresection followed by laser-mediated photodynamic therapy once the recurrent lesion was identified. The process involved application of topical 16% 5-aminolevulinic acid gel and suppository in the anal canal by a sterile cotton piece left for 3 hours. Subsequently, the lesion was irradiated for 20 min via an anal speculum using a 635nm laser beam at 120 J/cm² intensity (FD-400-B, linyun photoelectronic system co. Ltd, China).

From week 6.5, the patient received topical 5% imiquimod cream application into the anal canal every week for 9 weeks. On week 16, we confirmed that her previous lesions have resolved based on physical examination and a negative acetowhite test [Figure 3]. There were no recurrent lesions during the subsequent 8-year follow-up. The patient only reported intense burning sensation during laser application, and no other complications were observed. The course of the treatment is presented in Table 1.

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Figure 3:

No recurrent lesion in anal canal

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Buschke-Lowenstein tumor in anal canal is a rare disease, with a high recurrence rate.² The surgical treatment represents the first-line therapy.³ However, complications such as anal reconstruction or stenosis are quite common postoperatively. There is limited literature on anal condyloma acuminatum cases being treated with photodynamic therapy ⁴ Recurrences in our case was probably caused by incomplete resection of the condyloma lesion inside the anal canal. Laser-mediated photodynamic therapy with 5-aminolevulinic acid is an emerging approach for treating genital HPV infection.⁵ Several studies have suggested the administration of topical aminolevulinic acid along with photodynamic therapy is an effective, safe, and well-tolerated treatment for condyloma acuminatum, and more importantly, associated with low recurrence rate.⁶ In our case, laser-mediated photodynamic therapy was beneficial in ablating the residual tiny and latent lesions. With our previous experiences in treating and preventing the recurrence of cervical condyloma accuminatum, we prescribed topical 5% imiquimod cream on both perianal skin and anal canal for the patient weekly for latent lesions.⁷ Since week 16, no recurrences have been observed involving both external and internal anal region.

In summary, we recommend electroresection to resect the entire visible lesion and preserve anal function. Subsequently, the combined application of laser-mediated photodynamic therapy and topical 5% imiquimod cream can remarkably reduce the recurrence rate for Buschke-Lowenstein tumor in anal canal . Moreover, the long-lasting efficacy of combined treatment reduces the physical inconvenience for the patients and saves the cost of treatment. We consider this effective and acceptable therapy was worthy of clinical application.