A 33-year-old man presents to the office requesting removal of a lesion on his left hand. The growth has been present for several years and is asymptomatic. The patient is in good health and denies a personal history of skin cancer. He reports that he occasionally frequents an indoor tanning salon. His mother underwent treatment for skin cancer twice but the patient is uncertain of the cancer types. Physical examination reveals a smooth-surfaced, blue-black papule. No similar lesions are noted elsewhere.
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Biopsy of the lesion confirms the clinical diagnosis of blue nevus, revealing a collection of dendritic cells within the dermis. A typical blue nevus presents as a blue-black or slate-blue macule or papule measuring less than 0.5 cm in diameter. Common locations include the face, scalp, and extremities. Lesions are usually acquired but uncommonly may be congenital and reach substantial size.1 Blue nevus can also be found in the oral mucosa and eye.2,3
Dermoscopy of blue nevus is usually diagnostic, revealing a bluish or steel-blue homogeneous pattern. Presence of structures such as globules, dots, and pigment networks is variable.4 Histology is positive for HMB-45 (Gp100), S-100, and Melan-A/Mart-1 expression.5
Malignant transformation of a blue nevus is rare. High-risk lesions are greater than 3.0 cm, multinodular, and located primarily on the scalp.5 Malignant lesions are prone to recurrence and metastatic spread to lymph nodes.6
Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Cullom ME, Fraga GR, Reeves AR, Bhavsar D, Andrews BT. Giant congenital blue nevus presenting as cutis verticis gyrata: a case report and review of the literature. Ann Otol Rhinol Laryngol. 2021;130(12):1407-1411. doi:10.1177/00034894211007236
2. Mark HI, Kaplan SI. Blue nevus of the oral cavity. Review of the literature. Oral Surg Oral Med Oral Pathol. 1967;24(2):151-157. doi:10.1016/0030-4220(67)90254-x
3. Sayed-Ahmed I, Murillo JC, Monsalve P, et al. Blue nevi of the ocular surface: clinical characteristics, pathologic features, and clinical course. Ophthalmology. 2018;125(8):1189-1198. doi:10.1016/j.ophtha.2018.02.006
4. Di Cesare A, Sera F, Gulia A, et al. The spectrum of dermatoscopic patterns in blue nevi. J Am Acad Dermatol. 2012;67(2):199-205. doi:10.1016/j.jaad.2011.08.018
5. Daltro LR, Yaegashi LB, Freitas RA, Fantini BC, Souza CD. Atypical cellular blue nevus or malignant blue nevus? An Bras Dermatol. 2017;92(1):110-112. doi:10.1590/abd1806-4841.20174502
6. Zyrek-Betts J, Micale M, Lineen A, et al. Malignant blue nevus with lymph node metastases. J Cutan Pathol. 2008;35(7):651-657. doi:10.1111/j.1600-0560.2007.00878.x