Melanoma and melanoma in-situ diagnosis after excision of atypical intraepidermal melanocytic proliferation: A retrospective cross-sectional analysis

Abstract

Background: There is little evidence to guide surgical management of biopsies yielding the histologic descriptor "atypical intraepidermal melanocytic proliferation" (AIMP).Objective: Determine frequency of and factors associated with melanoma and melanoma in-situ (MIS) diagnoses after excision of AIMP and evaluate margins used to completely excise AIMP.Methods: Retrospective, cross-sectional study of 1127 biopsies reported as AIMP and subsequently excised within one academic institution.Results: Melanoma (in-situ, stage 1A) was diagnosed after excision in 8.2% (92/1127) of AIMP samples. Characteristics associated with melanoma/MIS diagnosis included age 60-79 (OR 8.1, 95% CI 2.5-26.2), age ≥80 (OR 7.2, 95% CI 1.7-31.5), head/neck location (OR 4.9, 95% CI 3.1-7.7), clinical lesion partially biopsied (OR 11.0, 95% CI 6.7-18.1), and lesion extending to deep biopsy margin (OR 15.1, 95% CI 1.7-136.0). Average surgical margin used to excise AIMP lesions was 4.5mm (SD 1.8).

Defining the Histopathological Term Atypical Intraepidermal Melanocytic Proliferation: A Retrospective Cross-Sectional Study

“…Blank et al performed a larger study and found a comparable rate of diagnostic change of AIMP to MIS of 8.2% (92/119). 4 The rate found by Blank et al is higher than that seen in our study and in the study by Zhang et al This may be due to variability in sampling because Blank et al had a higher study population. However, it may also reflect variability in how the term AIMP may be used by different pathologists because it is a subjective histopathological descriptive term, and not a distinctive entity.…”

“…Anatomical location on head or neck, and acral sites has been previously reported as a risk factor for diagnosis change from AIMP to melanoma. 2,4 Various reasons are given to 8), melanotic macule (5), solar lentigo (5), simple lentigo (4), junctional nevus (3), lichen-planus-like keratosis (1), benign pigmented acanthoma (1), and no melanocytic proliferation identified (3). explain this.…”

“…This association has previously been reported. 2,4 It is believed a deep shave biopsy, with the intent of removing the entire lesion, or ideally an excisional biopsy is superior to the punch method for evaluation of melanocytic lesions because it allows a more accurate representation of the lesion architecture. 2,5 It permits an assessment of a wider and more representative area, rather than a limited sample area.…”

Confocal microscopy, dermoscopy, and histopathology features of atypical intraepidermal melanocytic proliferations associated with evolution to melanoma in situ

“…Zhang et al 1 also reported that a high percentage of lesions diagnosed as AIMP on a biopsy and excised afterward were MIS (up to 20%). Recently, Blank et al 15 reported that melanoma was diagnosed after excision in 8.2% of AIMP samples and described some clinical features related to the melanoma subsequent diagnosis, but no dermoscopic or microscopic features were reported. In our series, all lesions were entirely mapped by RCM initially at baseline, and the more atypical areas were biopsied, which minimized the change of the postoperative diagnosis in our series.…”

“…also reported that a high percentage of lesions diagnosed as AIMP on a biopsy and excised afterward were MIS (up to 20%). Recently, Blank et al 15 . reported that melanoma was diagnosed after excision in 8.2% of AIMP samples and described some clinical features related to the melanoma subsequent diagnosis, but no dermoscopic or microscopic features were reported.…”