INTRODUCTION
Postinflammatory hyperpigmentation (PIH) is an acquired increase in melanin in response to inflammation or injury, including surgical intervention.1,2 PIH has been shown to have a significant impact on quality of life and may persist for years.3,4 In fact, data show that dyschromia is the most common patient outcome resulting in malpractice claims in dermatology.5 Individuals with eumelanin-rich skin are particularly susceptible to this long-lasting and highly distressing sequela.6
PIH occurs most noticeably among individuals with skin of color (SOC).7,8 Increased melanocyte activity and hypertrophy stimulate melanogenesis and melanin transfer to neighboring keratinocytes may be stimulated by cutaneous injury and/or dermatologic procedures.2 While PIH following laser and light-based procedures is well-studied in the literature,9-12 PIH following cutaneous surgery is poorly studied.13
Various modifiable factors are considered during surgical planning including repair type, wound closure material, and suture technique.15 Our study aims to characterize patient- and procedure-specific factors that contribute to PIH following MMS in order to educate surgeons on approaches to mitigate the development of PIH.
PIH occurs most noticeably among individuals with skin of color (SOC).7,8 Increased melanocyte activity and hypertrophy stimulate melanogenesis and melanin transfer to neighboring keratinocytes may be stimulated by cutaneous injury and/or dermatologic procedures.2 While PIH following laser and light-based procedures is well-studied in the literature,9-12 PIH following cutaneous surgery is poorly studied.13
With the rapidly changing demographic of the United States and rising rates of keratinocyte carcinoma,14 understanding factors contributing to PIH following Mohs micrographic surgery (MMS) is of particular importance. Postoperative PIH may be due to intraoperative injury, postoperative injury, or postoperative inflammation.13
Various modifiable factors are considered during surgical planning including repair type, wound closure material, and suture technique.15 Our study aims to characterize patient- and procedure-specific factors that contribute to PIH following MMS in order to educate surgeons on approaches to mitigate the development of PIH.
MATERIALS AND METHODS
A retrospective study, approved by the Albert Einstein College of Medicine Institutional Review Board, was conducted at Montefiore Medical Center, a single academic institution located in the Bronx, New York. Individuals with SOC and a biopsy proven diagnosis of keratinocyte carcinoma resected by MMS during a 12-month period (2020 to 2021) were included in this study. SOC individuals were defined as those of Hispanic/Latino, Asian, African, Native American, or Pacific Island decent and mixtures thereof,16,17 or individuals with Fitzpatrick skin type (FST) IV to VI.18,19 Demographic information collected included race/ethnicity, sex, age at time of MMS, and immunosuppressed status. Race and ethnicity were determined by patient self-identification as available in the electronic medical record. Spanish as a preferred language was used as a proxy for Hispanic ethnicity. FST was determined during the surgical visit. Individuals were designated as immunosuppressed if they had a history of human immunodeficiency virus or acquired immunodeficiency syndrome, organ transplantation, or systemic immunosuppression.
Tumor/donor site location was characterized as high (H), medium (M), or low (L) risk as outlined in the 2012 Appropriate Use Criteria for Mohs micrographic surgery.20 MMS outcomes including number of Mohs stages to achieve tumor clearance, defect size, subcutaneous suture material and size, and epidermal suture material and size were analyzed. Two of the authors (DH and RW) served as primary surgeons for each case. Postoperative care was standardized to the use of non-stick gauze with petrolatum or mupirocin 2% ointment. All participants were assessed postoperatively in person by the primary surgeons. High-quality digital photographs of the surgical site were captured postoperatively at several timepoints including immediately post-op, at the time of suture removal corresponding to the 7th or 14th day postoperatively as well as at 6 weeks and/or 10 weeks postoperatively.
Two dermatology residents retrospectively assessed photographs for the presence or absence of PIH, defined clinically as hyperpigmented macules or patches in the same distribution as the initial injury/ inflammatory process,1 ie, along the site of tumor extirpation and/or surgical repair, as a binary variable. For full-thickness skin grafts, PIH was evaluated around the periphery of the graft and not within the graft itself, given that graft color mismatch is common regardless of FST.21,22 Postoperative complications including dehiscence, necrosis, infection, and hematoma were noted. Data were analyzed using independent t-test, chi-square, Fisher exact, and logistic regression where appropriate in SPSS version 27.
RESULTS
Eighty-three cases in 72 SOC individuals were included in this study. Hispanic individuals represented 81.9% of the cases and Black individuals comprised 10.8%. PIH was more common in individuals with FST IV to V compared to FST II to III (48.0% vs 18.2%; P=0.006; Table 1).
Individuals who developed PIH were similar in age, sex, and immunosuppressed status compared to those who did not (Table 1). Grafts and granulation led to a higher rate of PIH compared to layered linear repairs and flaps (87.5% vs 30.7%; P=0.003; Table 2). Cases with any postoperative
