Clinical and Dermoscopic Features Associated With Difficult-to-Recognize Variants of Cutaneous Melanoma

Abstract

The clinical and dermoscopic features of the vast majority of uncommon variants of cutaneous melanoma have been rarely reported, leading to difficulty in making accurate diagnoses.OBJECTIVE To define the main clinical and dermoscopic features of the most frequently reported but uncommon histologic variants of cutaneous melanoma.EVIDENCE REVIEW A 2-step systematic review of the literature was performed (from inception to November 2018) using PubMed, Embase, and Cochrane Central Register of Controlled Trials databases. The first step identified those uncommon variants of melanoma for which at least 1 case reporting dermoscopy was described in the literature. The keywords searched were melanoma, uncommon, rare, dermoscopy, and dermatoscopy. In the second step, each previously identified uncommon variant was searched for in the same databases by combining the following terms with melanoma, dermoscopy, and dermatoscopy: amelanotic, hypopigmented, animal, melanocytoma, balloon, desmoplastic, follicular, nested, nevoid, dermal, spitz*, spindle, and verrucous. The institution's database was also searched from January 2012 to September 2019 for histopathologically confirmed cases of the same melanoma variants. Each reviewer also assessed the quality of reporting in the included articles based on previously described guidelines.FINDINGS In total, 62 articles met the inclusion criteria, reporting 433 melanoma cases. An additional 56 cases of uncommon melanoma variants were retrieved from the institution's database for a total of 489 cases: 283 cases of amelanotic superficial spreading melanoma, 18 cases of animal-type and pigmented epithelioid melanocytoma, 7 cases of balloon cell melanoma, 71 cases of desmoplastic melanoma, 3 cases of follicular melanoma, 10 cases of nested melanoma, 33 cases of nevoid melanoma, 2 cases of primary dermal melanoma, 57 cases of spitzoid melanoma, and 5 cases of verrucous melanoma. These variants of melanoma occurred more frequently in women than men (147 cases vs 132 cases). Clinically, these tumors were mainly palpable (162 of 217 [74.7%]) or amelanotic (283 of 489 [57.9%]) lesions that could resemble other benign or malignant skin conditions; dermoscopy typically revealed a homogeneous pinkish background, white structures, and polymorphic vessels. The mean age of all included was 58 years (range, 1-89 years).CONCLUSIONS AND RELEVANCE Uncommon melanoma variants may resemble both inflammatory disorders and other cutaneous neoplasms, representing a diagnostic pitfall even for the most experienced dermatologist. The purpose of this systematic review was to provide an extensive and detailed overview of specific clinical and dermoscopic features of each uncommon melanoma variant, highlighting the main criteria for differentiating these variants from other benign or malignant skin lesions.

Dermoscopy and reflectance confocal microscopy of balloon cell nevi: a series of 10 cases

“…These kinds of cells are described not only in benign nevi including Spitz, combined halo, dysplastic, nodal, and blue nevi, [12][13][14][15][16] but also in malignant lesions, such as in melanoma of the skin, choroid, or conjunctiva. 3,[17][18][19] No clinical features are suspect to the diagnosis, and single case reports are described in the literature showing different In our cases, each BCN was a smooth brownish macular lesion, confirming the aspect of common nevus reported in the literature. The most common location reported is the head and neck area.…”

“…Ballooning cell changes would be caused by an arrest of biosynthesis of melanin and would reflect an intrinsic cellular degenerative process, resulting in less pigmented than typical melanocytes. These kinds of cells are described not only in benign nevi including Spitz, combined halo, dysplastic, nodal, and blue nevi, 12–16 but also in malignant lesions, such as in melanoma of the skin, choroid, or conjunctiva 3,17–19 …”

Association between the dermoscopic morphology of peripheral globules and melanocytic lesion diagnosis

“…Given the importance of change as a concerning feature of malignancy, 5 it is only natural that this PG pattern may induce anxiety among dermoscopists. To complicate matters, PGs have also been seen in melanoma, especially follicular and naevoid melanoma 6 . In fact, studies have found different frequencies of melanomas among PG lesions, ranging from 0 to 28% 7–9 …”

Diagnosis and management of cutaneous melanoma

“…Clinical signs of invasion may include a palpable component and dermoscopic features such as milky pink or blue-grey structureless areas, chrysalis structures (white streaks) and polymorphous vessels ( Figure 1). 2,3 Importantly, some melanomas (nodular and desmoplastic subtypes in particular) may be pink or skin-coloured and relatively featureless ( Figure 2). 2,4 An individual's underlying risk should be considered when assessing lesions of concern and tailoring surveillance.…”