This article is more than 5 years old. Information may no longer be current.

Dermoscopy effective in evaluating desmoplastic melanoma

Dermoscopy was useful in the evaluation of clinically equivocal lesions or lesions with benign appearance during desmoplastic melanoma diagnosis, according to study results.

In a retrospective case series, researchers studied 37 patients (mean age, 69 years; 60% men) with desmoplastic melanoma (DM), confirmed by histopathic analysis. High-quality dermoscopic images of each case were available.

All patients had fair skin, and 78% had fewer than 20 nevi. Twenty-five percent of patients had a history of melanoma. The most frequent melanoma subtype associated with DM was lentigo maligna (LM). Eighty-seven percent of DM presented as palpable and/or indurated lesions, with 89% located on sun-exposed skin. Pure DM was classified in 43% of patients, and mixed DM in 57% of cases.

“Pure DM lesions were thicker than mixed DM lesions [Breslow depth mean, 4.10 mm vs. 2.83 mm; P=.22] and were less likely to have an associated epidermal non-DM component [63% vs. 100%; P=.004],” the researchers said.

When examined dermoscopically, 57% of DMs lacked melanocytic structures; however, all lesions had at least one melanoma-specific structure, with atypical vascular structures occurring most frequently (81%). Peppering, or granularity, was seen in 44% of pure DM compared with 24% in mixed DM. Crystalline structures, polymorphous vessels and vascular blush were observed more frequently in mixed DM.

“This study demonstrates that dermoscopy is a useful aid during the evaluation of clinically equivocal lesions or those with a benign appearance,” the researchers concluded. “Although DM can be difficult to diagnose based on clinical morphologic characteristics alone, clinical information and risk factor for DM need to be considered when evaluating indurated and firm lesions on sun-damaged skin, including male sex, older age, chronic sun exposure, and the presence of an associated LM. In addition, all lesions suggestive of LM should be palpated and evaluated with dermoscopy.”