Malignant melanoma clinically mimicking pyogenic granuloma: comparison of clinical evaluation and histopathology

摘要

Amelanotic melanomas (AMMs) account for a small proportion of all melanomas. They pose a risk of delayed diagnosis and, consequently, poor prognosis. AMMs may atypically present as a pyogenic granuloma-like lesion. This study sought to investigate the prevalence and clinical and histological features of AMM masquerading as pyogenic granuloma. The database of a tertiary medical center was screened for all patients pathologically diagnosed with melanoma in 2005-2016. Those with a suspected primary (i.e. pre-excision) clinical diagnosis of pyogenic granuloma were identified, and their demographic, clinical, histologic, and outcome data were collected from the medical files. Of 2038 patients diagnosed with melanoma, 10 (approximate to 0.5%) had a pyogenic granuloma-like AMM. The mean +/- SD age at lesion presentation was 56 +/- 18.9 years and the mean time from lesion appearance to diagnosis was 91.5 +/- 117.1 months. Nine tumors were located on the skin surface, and one on the oral mucosa. The mean lesion size was 19.6 +/- 14.1mm(2) and the mean Breslow's depth was 6.47 +/- 3.1mm; all tumors presented in the vertical growth phase. Seven (70%) patients had lymph node involvement or metastasis at diagnosis. Two patients died of the disease within 1 year of diagnosis. Given the potential lethality of AMM and the benign nature of pyogenic granuloma, clinician recognition of pyogenic granuloma-like AMMs is crucial. In the presence of a pyogenic granuloma-like lesion, findings of older patient age and large tumor size should raise the index of suspicion and prompt a biopsy study, thereby ensuring early and accurate treatment. Copyright (c) 2018 Wolters Kluwer Health, Inc. All rights reserved.