Dermoscopic Changes Observed in Slow-Growing Melanomas
Dermoscopic Changes Observed in Slow-Growing Melanomas
Background Melanomas vary in growth rate from rapidly developing nodular melanomas to slow-growing melanomas (SGM) that hardly change over years.
Objectives To evaluate longitudinal changes in dermoscopic findings of SGM.
Methods We retrospectively analysed a dermoscopic image dataset from 15 pigmented lesion clinics, of SGM that were followed sequentially by digital dermoscopy for at least 1 year. We evaluated baseline and follow-up images for changes in global pattern, organization, colours, structure and size.
Results Our series consisted of 92 SGM. On follow-up, these melanomas developed the following dermoscopic findings: more homogeneous and less reticular global dermoscopic pattern; more frequent disorganization of pattern (baseline, 67% vs. follow-up, 79%); decreased prominence of light brown colour, increased prominence of dark brown colour, and increased frequency of the colours red, white, grey, blue and black (baseline: 29%, 3%, 18%, 6% and 33% vs. follow-up: 41%, 10%, 31%, 13% and 45%, respectively); decrease in prominence of dermoscopic structure of pigmented network, with a concomitant increase in prominence of structureless areas; and increased prominence or new appearance of melanoma-specific dermoscopic structures, including negative network, blue–white structures and blotches. The majority of lesions (75%) remained the same size or grew by < 2 mm in diameter. An increase in lesion size was associated with change in the total number of colours and structures (χ = 14·3, P = 0·027) at follow-up.
Conclusions While their diameter changed minimally over time, most SGM became more disorganized, revealed loss of network in favour of structureless areas, and developed new colours.
The term melanoma defines the malignant neoplasm of melanocytes. Like most types of cancers, melanoma is actually a diagnosis that encompasses a broad range of clinical presentations and biological behaviours; for example, nodular melanoma presents as a rapidly growing tumour, while lentigo maligna tends to grow slowly over many years.
In an effort to further characterize melanomas that grow slowly, Argenziano et al. used dermoscopy to investigate the growth patterns of 103 histologically confirmed melanomas, for which sequential dermoscopic images over at least 1 year were available prior to excision. Briefly, for each melanoma, the authors compared baseline with follow-up dermoscopic images with respect to change in size, symmetrical or asymmetrical change in dermoscopic structures, and development of melanoma-specific criteria. The dataset included in situ (48%) and early invasive (52%) melanomas excised after follow-up time that ranged from 12 to 120 months. During this period, the majority of melanomas either remained the same size (16%) or showed a relatively small, 1–2 mm increase in diameter (59%) compared with baseline images. While most melanomas (63%) developed asymmetrical structural changes, new melanoma-specific criteria developed in only one-third of the lesions. It is noteworthy that five of the 103 lesions were histopathologically diagnosed as naevus-associated melanoma, suggesting that the majority of the lesions were, in fact, melanomas at initial consultation.
In their study, Argenziano et al. presented important evidence that supports the existence of a subset of melanomas that are slow-growing. The image dataset that was used in their publication is a unique resource of melanomas followed longitudinally with high-quality dermoscopic imaging. Herein, we aimed to glean further insights into patterns of progression of slow-growing melanomas (SGM) by evaluating this melanoma dataset for longitudinal changes in global dermoscopic pattern, organization, colour and structure, and how these changes relate to lesion size.
Abstract and Introduction
Background Melanomas vary in growth rate from rapidly developing nodular melanomas to slow-growing melanomas (SGM) that hardly change over years.
Objectives To evaluate longitudinal changes in dermoscopic findings of SGM.
Methods We retrospectively analysed a dermoscopic image dataset from 15 pigmented lesion clinics, of SGM that were followed sequentially by digital dermoscopy for at least 1 year. We evaluated baseline and follow-up images for changes in global pattern, organization, colours, structure and size.
Results Our series consisted of 92 SGM. On follow-up, these melanomas developed the following dermoscopic findings: more homogeneous and less reticular global dermoscopic pattern; more frequent disorganization of pattern (baseline, 67% vs. follow-up, 79%); decreased prominence of light brown colour, increased prominence of dark brown colour, and increased frequency of the colours red, white, grey, blue and black (baseline: 29%, 3%, 18%, 6% and 33% vs. follow-up: 41%, 10%, 31%, 13% and 45%, respectively); decrease in prominence of dermoscopic structure of pigmented network, with a concomitant increase in prominence of structureless areas; and increased prominence or new appearance of melanoma-specific dermoscopic structures, including negative network, blue–white structures and blotches. The majority of lesions (75%) remained the same size or grew by < 2 mm in diameter. An increase in lesion size was associated with change in the total number of colours and structures (χ = 14·3, P = 0·027) at follow-up.
Conclusions While their diameter changed minimally over time, most SGM became more disorganized, revealed loss of network in favour of structureless areas, and developed new colours.
Introduction
The term melanoma defines the malignant neoplasm of melanocytes. Like most types of cancers, melanoma is actually a diagnosis that encompasses a broad range of clinical presentations and biological behaviours; for example, nodular melanoma presents as a rapidly growing tumour, while lentigo maligna tends to grow slowly over many years.
In an effort to further characterize melanomas that grow slowly, Argenziano et al. used dermoscopy to investigate the growth patterns of 103 histologically confirmed melanomas, for which sequential dermoscopic images over at least 1 year were available prior to excision. Briefly, for each melanoma, the authors compared baseline with follow-up dermoscopic images with respect to change in size, symmetrical or asymmetrical change in dermoscopic structures, and development of melanoma-specific criteria. The dataset included in situ (48%) and early invasive (52%) melanomas excised after follow-up time that ranged from 12 to 120 months. During this period, the majority of melanomas either remained the same size (16%) or showed a relatively small, 1–2 mm increase in diameter (59%) compared with baseline images. While most melanomas (63%) developed asymmetrical structural changes, new melanoma-specific criteria developed in only one-third of the lesions. It is noteworthy that five of the 103 lesions were histopathologically diagnosed as naevus-associated melanoma, suggesting that the majority of the lesions were, in fact, melanomas at initial consultation.
In their study, Argenziano et al. presented important evidence that supports the existence of a subset of melanomas that are slow-growing. The image dataset that was used in their publication is a unique resource of melanomas followed longitudinally with high-quality dermoscopic imaging. Herein, we aimed to glean further insights into patterns of progression of slow-growing melanomas (SGM) by evaluating this melanoma dataset for longitudinal changes in global dermoscopic pattern, organization, colour and structure, and how these changes relate to lesion size.