Favorable prognosis for malignant melanomas associated with acquired melanocytic nevi

Abstract

In a clinicohistopathologic study of 557 patients with primary cutaneous malignant melanoma, there were fewer metastases and/or deaths from melanoma when histologic evidence of a coexisting acquired melanocytic nevus was found. A total of 130 patients with melanocytic nevus and 427 cases of melanoma without histologic evidence of a nevus (denovo) were studied. Clinical follow-up evaluation for evidence of metastases and/or death was obtained. Only ten of the patients (7.7%) with nevus-associated melanoma had metastases and/or death v 78 (18.3%) with de novo melanoma. When stratified by lesion thickness, the logrank test for survival revealed a statistically significant difference between the two groups. An overall favorable outcome seen in patients with malignant melanomas associated with acquired melanocytic nevi was found, therefore, to be independent of lesion thickness as well as six other variables reported to be related to the biologic behavior of malignant melanoma. Thus, the presence of nevus cells in a specimen of malignant melanoma portends a better prognosis and may have important implications in the biology of this neoplasm.

Clinicopathological features and prognosis of patients with de novo versus nevus-associated melanoma in Taiwan

“…Friedman et al . reported that patients with nevus-associated melanomas had decreased rates of metastasis and death, but only for melanomas between 0.75 and 1.69 mm and greater than 3.6 mm in thickness [7]. Kaddu et al .…”

“…In fact, however, the criteria for defining melanomas as nevus-associated melanomas are a subject of some controversy [32]. Some reports have diagnosed nevus-associated melanomas based on patient anamnesis, whereas others have regarded the pathologically proven presence of nevus cells as diagnostic for nevus-associated melanomas [7, 28, 32]. In this regard, it should be noted that melanoma cells may change their shapes into nevus-like cells, such that a pathological examination alone may not be enough to judge for certain whether a given melanoma is associated with a nevus [7, 32].…”

“…Some reports have diagnosed nevus-associated melanomas based on patient anamnesis, whereas others have regarded the pathologically proven presence of nevus cells as diagnostic for nevus-associated melanomas [7, 28, 32]. In this regard, it should be noted that melanoma cells may change their shapes into nevus-like cells, such that a pathological examination alone may not be enough to judge for certain whether a given melanoma is associated with a nevus [7, 32]. Furthermore, while a patient history can be used to determine if a melanoma has arisen from a nevus, it can also lead to misdiagnosis due to the questionable accuracy of patient recall of a preexisting lesion [32].…”

RAS/RAF/MEK/ERK and PI3K/PTEN/AKT Signaling in Malignant Melanoma Progression and Therapy

“…Nevus-associated melanomas are transformants of preexisting benign lesions, and their malignant conversion progresses in a multistep manner [23–26]. De novo melanomas develop without pre-existing benign lesions [6, 27–29]. In humans, most melanomas are thought to have developed de novo.…”

Cutaneous melanoma associated with naevi prevalence: A 15‐year cross‐sectional retrospective study

“…Particularly, with regards to NAM, the presence of a melanoma-associated benign naevus component was indifferently considered, no matter the position of the naevus component cells which could be at the dermoepidermal junction contiguous to the melanoma, in the dermis below the melanoma, or in both configurations, and was assessed using previously defined criteria including an abrupt transition between benign melanocytic cells and the adjacent malignant cells, the presence of maturation, and the absence of cytologic atypia within the naevus component. 12,13 In addition, we studied the immunohistochemical staining patterns of melanoma and naevus cells within the naevus-associated tumours, which demonstrated a loss of cytoplasmic reactivity for HMB-45 and a lack of proliferation by negative staining for Ki-67 in naevus cells.…”