Abstract and Introduction
Spitzoid lesions represent a challenging and controversial group of tumours, in terms of clinical recognition, biological behaviour and management strategies. Although Spitz naevi are considered benign tumours, their clinical and dermoscopic morphological overlap with spitzoid melanoma renders the management of spitzoid lesions particularly difficult. The controversy deepens because of the existence of tumours that cannot be safely histopathologically diagnosed as naevi or melanomas (atypical Spitz tumours). The dual objective of the present study was to provide an updated classification on dermoscopy of Spitz naevi, and management recommendations of spitzoid-looking lesions based on a consensus among experts in the field. After a detailed search of the literature for eligible studies, a data synthesis was performed from 15 studies on dermoscopy of Spitz naevi. Dermoscopically, Spitz naevi are typified by three main patterns: starburst pattern (51%), a pattern of regularly distributed dotted vessels (19%) and globular pattern with reticular depigmentation (17%). A consensus-based algorithm for the management of spitzoid lesions is proposed. According to it, dermoscopically asymmetric lesions with spitzoid features (both flat/raised and nodular) should be excised to rule out melanoma. Dermoscopically symmetric spitzoid nodules should also be excised or closely monitored, irrespective of age, to rule out atypical Spitz tumours. Dermoscopically symmetric, flat spitzoid lesions should be managed according to the age of the patient. Finally, the histopathological diagnosis of atypical Spitz tumour should warrant wide excision but not a sentinel lymph-node biopsy.
Since its first description by Sophie Spitz, the morphological and biological spectrum of Spitz naevus has been extensively investigated.[1,2] Although initially described as 'juvenile melanoma', the benign nature of Spitz naevus was very soon understood. For several decades, this tumour was considered to be completely benign and cases of metastatic disease were assumed to represent incorrectly diagnosed melanomas mimicking a Spitz naevus.
However, in the late 1990s, cases of spitzoid lesions without malignant histopathological criteria but with the potential of nodal metastasis were described. This observation initiated a new era of controversies on the true biology of spitzoid neoplasms, characterized by the introduction of several terms attempting to classify spitzoid tumours with intermediate histopathological features between Spitz naevus and spitzoid melanoma (Spitz naevus with atypia and metastasis, metastasizing Spitz tumour, atypical Spitz tumour, atypical Spitz naevus, melanocytic tumour of unknown malignant potential, melanocytoma).[5–8] The controversies on terminology, classification and management strategies of these tumours continue to the present day.
The introduction of dermoscopy significantly improved the clinical recognition of Spitz naevi, as they were shown to exhibit a peculiar and characteristic pattern of dermoscopic structures. Pigmented variants were first investigated and shown to display the so-called 'starburst' pattern, consisting of a central area of homogeneous black-blue pigmentation and symmetrically distributed peripheral streaks or pseudopods.[9–11] Several additional patterns were later found to be associated with pigmented Spitz naevus, including globular, homogeneous, reticular and multicomponent pattern.
Another criterion initially reported to characterize melanoma but later shown to be rather predictive of Spitz naevus was the so-called negative pigment network or reticular depigmentation, consisting of white intermingled lines surrounding pigmented globules.
Studies on the dermoscopic morphology of nonpigmented Spitz naevi were subsequently conducted and suggested that these tumours more frequently display dotted vessels in a regular distribution.[14,15] The aforementioned negative pigment network was found to be present also in nonpigmented Spitz naevi, with the only difference being that the white lines surround vessels instead of pigmented globules.[13,16]
Several infrequent dermoscopic patterns have been also reported in Spitz naevi and suggested to correspond to peculiar histopathological variants such as angiomatoid or desmoplastic Spitz naevus.
Although dermoscopy provided further insights into the morphology of Spitz naevus, management of spitzoid lesions remains controversial. The main source of controversy is the fact that spitzoid melanoma might perfectly mimic a Spitz naevus, displaying one of the aforementioned dermoscopic patterns. This has been highlighted by studies reporting a high variability in clinicians' beliefs and behaviour. Two clinically relevant questions remain to be addressed: how to manage a spitzoid-looking lesion and how to manage a tumour histopathologically diagnosed as 'atypical spitzoid naevus or tumour'.
Our study had three aims: (i) to provide an updated dermoscopic classification of Spitz naevi based on a detailed search and review of the literature; (ii) to provide recommendations on the management of spitzoid lesions according to their clinical and dermoscopic morphology; and (iii) to provide recommendations on the management of histopathologically ambiguous spitzoid tumours.
The British Journal of Dermatology. 2017;177(3):645-655. © 2017 Blackwell Publishing