Extramammary Paget's disease (EMPD) is a rare skin cancer occurring in areas with abundant apocrine glands.[1] It generally presents as an erythematous, eczematous, or ulcerative rash with associated pruritus and pain. Treatment is difficult, as EMPD has a high recurrence rate[2] despite therapies including Mohs surgery, wide excision, topical imiquimod, and photodynamic therapy (PDT). Therefore, early detection of recurrence followed by appropriate treatment is crucial for a better prognosis. We hereby report the use of dermoscopy to monitor the recurrence of EMPD in four patients at our hospital.
A total of four histopathologically confirmed EMPD patients were identified at our institute. Demographic data, clinical, and dermoscopic images were acquired under informed consent. EMPD lesions occurred at the axilla in patient 1 and at the genital area in patients 2 to 4. Three patients received wide excision with clear surgical margins and patient 4 completed treatment with PDT and subsequent topical imiquimod [Table 1]. All patients were followed up at our hospital regularly with a mean duration of 2.5 years. Thorough clinical and dermoscopic surveys were done at each visit. Unfortunately, new asymptomatic red patches appeared at previous EMPD sites for all four patients [Figure [Figure1a1a and andb].b]. Dermoscopic examination showed milky-red areas for all patients [red asterisk, Figure Figure1c1c and and1d],1d], whereas white structureless areas [white asterisk, [Figure 1d] and polymorphous vascular patterns [black arrows, Figure 1d] were observed in patients 2 to 4. Glomerular vessel patterns were only noted at the scrotal lesions [red arrows, Figure 1d]. Each patient then received skin biopsy under dermoscopic guidance, which confirmed recurrent EMPD. Topical imiquimod was given to all patients and the erythematous patches faded.
Dermoscopy has been used to monitor treatment outcomes and post-treatment follow-up in skin cancers such as Bowen's disease, basal cell carcinoma, and squamous cell carcinoma.[3,4] Sampling bias from incisional biopsies could be prevented, as the entire skin lesion could be examined. Therefore, dermoscopy is a useful tool to assess and detect highly recurrent tumors such as EMPD, thus improving the clinical prognosis of the patient. Reported dermoscopic features of EMPD include milky-red areas, white structureless areas, polymorphous vascular patterns and glomerular vessel patterns, surface scales, ulcers, shiny white lines, and pigmentary structures.[5] In our study, similar dermoscopic findings could be seen in recurrent EMPD. Notably, vascular patterns were present at the scrotum but not at the axilla. Scrotal polymorphous and glomerular vessel patterns corresponded to the dilated and tortuous vessels in the superficial dermis [Figure 1f], which may reflect tumor-related neoangiogenesis. In the axilla lesion, however, no vascular patterns were detected under dermoscopy. Correlating dermatopathological findings also showed the absence of dilated vessels in the superficial dermis [Figure 1e]. We speculated that the papillomatous epidermis and thicker dermis of the axilla may mask the vascular elements under dermoscopy.
In conclusion, dermoscopy is a useful tool for monitoring treatment outcome and detecting recurrent EMPD. Primary and recurrent EMPD have similar dermoscopic features; thus, the re-emergence of milky-red areas may forebode the relapse of EMPD.
Authors: Wei-Cheng Fang, Pei-Chien Chou, Li-Wen Chiu,Chiao-Li Ke and Shih-Tsung Cheng
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