Dermatoscopy of Verrucous Pigmented Lesions is Essential for Choosing the Appropriate Treatment

Verrucous Melanoma of the Scalp Initially Misdiagnosed as Seborrheic Keratosis

Verrucous melanoma (VM) is a rare entity that presents diagnostic difficulty on both clinical and histopathologic grounds. Clinically, this tumor can be mistaken for a benign non-melanocytic lesion, particularly seborrheic keratosis (SK), as they both share several similarities, such as the homogenous pigmentation, the verrucous surface, and the roughly well-defined borders. In our patient’s case, her verrucous lesion was initially misdiagnosed as SK by a general practitioner two months prior to her admission. Upon physical examination, the lesion was indeed suggestive of SK but a VM was not discarded. Biopsy revealed melanoma. Standard treatment of SK often includes electrodesiccation or cryotherapy, which potentially might worsen and delay the diagnosis of melanoma with subsequent implications for therapeutic management and prognosis. We report this case to increase awareness and knowledge about VM, which may lead to earlier diagnosis and improved outcomes.

Unusual Clinical Presentations of Malignant Melanoma: A Review of Clinical and Histologic Features with Special Emphasis on Dermatoscopic Findings

This review presents the main challenges encountered when diagnosing unusual variants of malignant melanoma with the aim of raising awareness to allow application of the most appropriate treatment strategies. Although these melanomas are often rare, their misdiagnosis potentially jeopardizes patients' health and survival, and has medicolegal implications. The clinical and histologic presentations of melanoma vary greatly, and assessment of uncommon melanomas can be difficult for practitioners because of their scarcity and resemblance to other dermatologic entities. The most problematic melanoma types are desmoplastic melanoma, polypoid melanoma, primary dermal melanoma, verrucous malignant melanoma, pigmented epithelioid melanocytoma, mucosal melanoma, follicular melanoma and melanoma with non-melanocytic differentiation. The two most difficult-to-diagnose subtypes of melanoma are the nevoid and the amelanotic melanomas. Some specific attributes of these variants can be more easily recognized with digital dermatoscopy, facilitating early detection and possibly avoiding invasive procedures. Key cases with the most notable clinical, dermatoscopic, and histopathologic features are presented, highlighting the practical issues of making an accurate diagnosis and choosing the best therapy.