Ancient Blue Nevi (Cellular Blue Nevi With Degenerative Stromal Changes)Cerroni, Lorenzo MD*; Borroni, Riccardo G MD*†; Massone, Cesare MD*; Kerl, Helmut MD*American Journal of Dermatopathology: February 2008 - Volume 30 - Issue 1 - pp 1-5 doi: 10.1097/DAD.0b013e31815b7530 Original Article Abstract Author Information Ancient melanocytic nevi are benign melanocytic neoplasms that show degenerative and atypical changes, sometimes leading to a misdiagnosis of melanoma. We describe 6 patients (M:F ratio 4:2; age range, 15-84 years; median, 50 years) who presented with cellular blue nevi showing stromal changes resembling those of ancient melanocytic nevi. The lesions were located on the buttocks (4 patients) and on the trunk (2 patients) and clinically consisted of heavily pigmented nodules. Histology revealed the architectural pattern of cellular blue nevi. However, the architecture was strikingly altered by stromal changes like those seen in ancient melanocytic nevi, including increased number of large, dilated vessels with pseudoangiomatous features in 4 cases, hyaline angiopathy in 4 cases, myxoid changes, sclerosis or hyalinization of the stroma in all cases, and variable amounts of edema in 4 cases. In 2 cases, a large edematous area was present in the center of the lesion, and nests of ovoidal melanocytes and single dendritic melanocytes appeared to “float” in the stroma. Pleomorphic melanocytes were observed in all cases. Ancient blue nevi represent a morphologic variation of cellular blue nevi-Masson neuronevi with degenerative stromal changes. Recognition of these lesions can help prevent overdiagnosis of melanoma. From the *Department of Dermatology, Medical University of Graz, Austria; and †Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy. Reprints: Lorenzo Cerroni, MD, Department of Dermatology, Medical University of Graz, Auenbruggerplatz 8, A-8036 Graz, Austria (e-mail: firstname.lastname@example.org). © 2008 Lippincott Williams & Wilkins, Inc.