Plaque-type blue nevus combined with nevus spilus and smooth muscle hyperplasia
Version of Record online: 25 DEC 2001
International Journal of Dermatology
Volume 38, Issue 10, pages 775–777, 1999 October
How to Cite
Park, Y. M., Kang, H. and Cho, B. K. (1999), Plaque-type blue nevus combined with nevus spilus and smooth muscle hyperplasia. International Journal of Dermatology, 38: 775–777. doi: 10.1046/j.1365-4362.1999.00811.x
- Issue online: 25 DEC 2001
- Version of Record online: 25 DEC 2001
A 31-year-old man presented with a large pigmented lesion, present since birth on his right upper aspect of his back. On examination, a speckled pigmented plaque measuring 9 × 5 cm was found on the right interscapular area. The plaque was composed of multiple dark-blue macules and papules with intervening areas of faint blue discoloration and brown patches overlapping the blue lesions ( Fig. 1). The lesion was slightly elevated, showing a gradual increase in height from its periphery toward its center. The lesion had enlarged as the patient grew, but there had been no change in color, size, or texture over the past few years. No other pigmentary changes were noted, and there was no family history of pigmentary disorders.
Three skin biopsy specimens were obtained. In the dark-blue papular and macular area, many melanin-laden cells were present in the mid to lower portion of the dermis; these aggregated around blood vessels, the cutaneous nerve, and the pilosebaceous apparatus, and were intimately mixed with irregularly arranged, slightly thickened collagen bundles ( Fig. 2). Many were spindle-shaped, bipolar, dendritic melanocytes, some extending into the subcutaneous tissue. A few melanophages were intermingled with the melanocytes. Some sections contained proliferations of thickened arrector pili muscles. In the brown patches overlapped by the faint blue background area, rete ridges were elongated and the levels of melanin and melanocytes in the epidermal basal layer were slightly increased. Numerous melanocytes were scattered in the mid to lower dermis. These features were consistent with a common blue nevus accompanied by nevus spilus and smooth muscle hyperplasia.
Immunohistochemical studies demonstrated a positive reaction of the tumor cells to vimentin and S-100 protein. In addition, many cells reacted to the antibody HMB-45, indicating the presence of premelanosomes. The patient did not wish to undergo surgical treatment, and it was recommended that the condition be monitored regularly to detect promptly any malignant changes.