In vivo confocal microscopy was used to visualize 8 cases of fibroepithelioma of Pinkus (FeP). Dermoscopically, there were 5 hypopigmented cases that were characterized by white intersecting lines associated with a vascular pattern and 3 pigmented cases that showed ulceration, patchy hypopigmented and hyperpigmented areas, and dark-brown dots.
In all cases, in vivo confocal microscopy revealed a distinct architecture that was visible at the level of the dermoepidermal junction. The hallmark of FeP was a fenestrated pattern constituted by “holes” that corresponded to the fibrous stroma (Figure, A and B [asterisks]), which was outlined by the tumoral islands or cords (the “frame” of the holes) (Figure, A and B, top [arrows]) that were particularly evident in hypopigmented FeP (Figure, A). Histopathologic examination revealed that both hypopigmented and pigmented lesions were characterized by tumor islands and anastomosing strands of basaloid cells (Figure, A and B, top [arrows]), usually with palisading at the periphery, surrounding a fibrous stroma Figure, A and B, top [asterisks]). In pigmented lesions, a variable amount of plump, bright cells (Figure, C, bottom [arrows]) corresponding to melanin-laden macrophages (Figure, C, top [arrow]) were also present. Histopathologically, all tumors demonstrated strands of basaloid keratinocytes located within an overwhelmingly fibrous stroma.
Longo C, Soyer HP, Pepe P, Casari A, Wurm EMT, Guitera P, Pellacani G. In Vivo Confocal Microscopic Pattern of Fibroepithelioma of Pinkus. Arch Dermatol. 2012;148(4):556. doi:10.1001/archdermatol.2011.945