Background: Simulators of malignant melanoma comprise a heterogenous group of melanocytic and nonmelanocytic lesions of the skin. Among frequent clinical mimickers of melanoma are injured melanocytic nevi. Any change in the clinical appearance of a pre-existing nevus should alert the clinician to exclude the possibility of malignant transformation in order to early identify a lesion at a stage when complete cure can still be achieved. Objective: The purpose of this study was to present the clinical, dermoscopic and histopathologic findings of a series of acquired melanocytic nevi which abruptly developed a pigmented peripheral halo, presumably following minor trauma. Methods: A series of 6 cases of acquired melanocytic nevi which suddenly developed a targetoid halo were included in the study. All lesions were evaluated by dermoscopy. Three cases were surgically removed at different stages of evolution and submitted to histopathologic examination. In all cases, follow-up was obtained. Results: All the lesions arose on trauma-prone skin sites of young women. The sudden development of an asymptomatic, targetoid halo on a long-lasting, acquired exophytic nevus was the main presentation. Whereas the central nevus persisted, the ecchymotic halo ultimately disappeared. Histopathologic examination disclosed changes of the traumatized nevus in the central part, whereas the ring showed hemorrhage and hemosiderin deposits. Increased numbers of small vessels with hobnail characteristics were associated features. Conclusions: Targetoid hemosiderotic nevus is a distinctive clinicopathologic variant of traumatized acquired melanocytic nevus which should be included in the list of clinical simulators of melanoma.

Ackerman AB, Cerroni L, Kerl H: Pitfalls in the Histopathologic Diagnosis of Malignant Melanoma. Philadelphia, Lea & Febiger, 1994.
LeBoit PE: Simulants of malignant melanoma: A rogue’s gallery of melanocytic and nonmelanocytic impostors. Pathol State Art Rev 1994;2:195–258.
Cerroni L, Kerl H: Simulators of malignant melanoma of the skin. Eur J Dermatol 1998;8:388–396.
Matz H, Orion E, Ruocco V, Wolf R: Clinical simulators of melanoma. Clin Dermatol 2002;20:212–221.
Maize JC, Ackerman AB: Pigmented Lesions of the Skin. Philadelphia, Lea & Febiger, 1987, pp 106–107.
James MP, Wells RS: Cockarde naevus: An unusual variant of the benign cellular naevus. Acta Derm Venereol 1980;60:360–363.
Mooney MA, Barr RJ, Buxton MG: Halo nevus or halo phenomenon? A study of 142 cases. J Cutan Pathol 1995;22:342–348.
Harvell JD, Meehan SA, LeBoit PE: Spitz’ nevi with halo reaction: A histopathologic study of 17 cases. J Cutan Pathol 1997;24:611–619.
Del Rio E, Aguilar A, Gallego MA, Tardio J, Sanchez Yus E: Targetoid halo nevus. J Am Acad Dermatol 1993;29:267–268.
Nicholls DS, Mason GH: Halo dermatitis around a melanocytic naevus: Meyerson’s naevus. Br J Dermatol 1988;118:125–129.
Nudenberg B: Halo nevi and vitiligoid phenomena in a case of melanoma. Med Cutan Ibero Lat Am 1979;7:45–49.
Smith MWE, Moseley JC: Multiple halo neurofibromas. Arch Dermatol 1976;112:987–990.
Barman A: Halo around a histiocytoma. Arch Dermatol 1978;114:1717–1718.
Migally M, Migally N: Halo seborrheic keratosis. Int J Dermatol 1983;22:307–309.
Santa Cruz D, Aronberg J: Targetoid hemosiderotic hemangioma. J Am Acad Dermatol 1988;19:550–558.
Guillon L, Calonje E, Speight P, Rosai J, Fletcher CDM: Hobnail hemangioma. A pseudomalignant vascular lesion with a reappraisal of targetoid hemosiderotic hemangioma. Am J Surg Pathol 1999;23:97–105.
Christenson LJ, Stone MS: Trauma-induced simulator of targetoid hemosiderotic hemangioma. Am J Dermopathol 2001;23:221–223.
Mentzel T, Partanen TA, Kutzner H: Hobnail hemangioma (targetoid hemosiderotic hemangioma): Clinicopathologic and immunohistochemical analysis of 62 cases. J Cutan Pathol 1999;26:279–286.
Franke FE, Steger K, Marks A, Kutzner H, Mentzel T: Hobnail hemangiomas (targetoid hemosiderotic hemangiomas) are true lymphangiomas. J Cutan Pathol 2004:31:362–367.
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