Bednár tumor associated with dermal melanocytosis: melanocytic colonization or neuroectodermal multidirectional differentiation?
Article first published online: 13 MAY 2003
Journal of Cutaneous Pathology
Volume 30, Issue 2, pages 147–151, February 2003
How to Cite
Goncharuk, V., Mulvaney, M. and Carlson, J. A. (2003), Bednár tumor associated with dermal melanocytosis: melanocytic colonization or neuroectodermal multidirectional differentiation?. Journal of Cutaneous Pathology, 30: 147–151. doi: 10.1034/j.1600-0560.2003.00030.x
- Issue published online: 13 MAY 2003
- Article first published online: 13 MAY 2003
- Accepted September 28, 2002
Background: Neuroectodermal differentiation or melanocytic colonization are the opposing theories of histogenesis for the Bednár tumor or pigmented dermatofibrosarcoma protuberans (DFSP).
Observation: A 31-year-old African-American woman presented with a 2-cm blue-black shoulder nodule of 1-year duration. Punch biopsy revealed a CD34+, Factor XIIIa-DFSP, harboring numerous, pigmented spindle S100+, Mart-1+ and HMB-45+ cells. Subsequent wide excision demonstrated pigmented dendritic and spindled cells widely scattered throughout the dermis of the 3-cm excisional margins and punch biopsy specimens of normal skin from both shoulders. This latter process was interpreted as dermal melanocytosis (nevus of Ito). The dermal pigmented spindle cells were Mart-1+ and CD34−, and were associated with non-pigmented CD34+, cytologically banal spindle cells, which were more numerous in the excisional margins than the contralateral shoulder.
Conclusion: Reported herein is a singular case of Bednár tumor associated with dermal melanocytosis. Although the coexistence of these processes implicates colonization of the DFSP by constituent dermal melanocytes, the mixed immunophenotype (CD34+ or Mart-1+ cells) of dispersed dermal spindle cells hints at the possibility of a common cell of origin: the putative neuromesenchymal cell. In effect, the Bednár tumor could represent one part of a spectrum of neural crest-derived dermal tumors that includes dermal melanocytosis, cellular blue nevus and conventional DFSP.