Dermatoscopic features of cutaneous non-facial and non-acral lentiginous growth pattern melanomas

Abstract

Background:The dermatoscopic features of facial lentigo maligna (LM), facial lentigo maligna melanoma (LMM) and acral lentiginous melanoma (ALM) have been well described. This is the first description of the dermatoscopic appearance of a clinical series of cutaneous non-facial non-acral lentiginous growth pattern melanomas.Objective:To describe the dermatoscopic features of a series of cutaneous non-facial non-acral lentiginous growth pattern melanomas in an Australian skin cancer practice.Method:Single observer retrospective analysis of dermatoscopic images of a one-year series of cutaneous non-facial, non-acral melanomas reported as having a lentiginous growth pattern detected in an open access primary care skin cancer clinic in Australia. Lesions were scored for presence of classical criteria for facial LM; modified pattern analysis (“Chaos and Clues”) criteria; and the presence of two novel criteria: a lentigo-like pigment pattern lacking a lentigo-like border, and large polygons.Results:20 melanomas occurring in 14 female and 6 male patients were included. Average patient age was 64 years (range: 44–83). Lesion distribution was: trunk 35%; upper limb 40%; and lower limb 25%. The incidences of criteria identified were: asymmetry of color or pattern (100%); lentigo-like pigment pattern lacking a lentigo-like border (90%); asymmetrically pigmented follicular openings (APFO’s) (70%); grey blue structures (70%); large polygons (45%); eccentric structureless area (15%); bright white lines (5%). 20% of the lesions had only the novel criteria and/or APFO’s.Limitations:Single observer, single center retrospective study.Conclusions:Cutaneous non-facial non-acral melanomas with a lentiginous growth pattern may have none or very few traditional criteria for the diagnosis of melanoma. Criteria that are logically expected in lesions with a lentiginous growth pattern (lentigo-like pigment pattern lacking a lentigo-like border, APFO’s) and the novel criterion of large polygons may be useful in increasing sensitivity and specificity of diagnosis of these lesions. Further study is required to establish the significance of these observations.

Standardization of terminology in dermoscopy/dermatoscopy: Results of the third consensus conference of the International Society of Dermoscopy

“…For example the term “zig-zag pattern” 36 (similar to “polygons” 98 or “angulated lines” 99 ) that has been introduced to describe a specific clue to lentigo maligna is relatively new but relatively high up on the familiarity level when compared with other terms published in the same year. Familiarity and usage in the community are important measures of the practical utility and we used them as objective criteria for inclusion in the standardized dictionary.…”

“…An example would be the family “rhomboids,” “polygons,” “angulated lines,” and “zig-zag pattern.” “Rhomboids” was introduced years ago 107 to describe the angulated pigmented lines around follicular openings in lentigo maligna (the new term “zig-zag” pattern 36 can be regarded as a variant of rhomboids on facial skin). “Angulated lines” 99 and “polygons” 98 and have been introduced recently to characterize pigmented lines that form angles in flat melanomas on nonfacial, sun-damaged skin (Fig 3, B ). Although we acknowledge that the 4 terms describe similar structures we separated “rhomboids” and “zig-zag pattern” from the other 2 because “rhomboids” and “zig-zag pattern” are reserved for facial skin and the others are used for nonfacial skin.…”

Lentigo Maligna and Lentigo Maligna Melanoma: Contemporary Issues in Diagnosis and Management

“…Additional criteria that have been more recently described include increased vascular network density, red rhomboidal structures and target patterns [27]. For nonfacial LM, asymmetrically pigmented follicular openings and large polygonal structures are useful dermoscopic clues [28]. Use of dermoscopy has also been shown to enhance the detection of the clinical margins of LM [29].…”

The limitations of dermoscopy: false‐positive and false‐negative tumours

“…To minimize this risk, management rules based on the overall patient's context have been suggested . Furthermore, three new predictors of melanoma in situ have been recently introduced: irregular hyperpigmented areas, prominent skin markings and angulated lines (polygons), the latter two mainly seen on sun‐damaged skin Nevoid melanoma represents a rare melanoma subtype that clinically and histopathologically mimics a naevus and develops usually in elderly individuals.…”