To investigate
biological characteristics of
syringomas, three-dimensional (3-D) architectures of epithelial
tumor nests and
luminal structures of
syringomas, hair follicles, and epidermal basement membrane in skin lesions were reconstructed using a computer stereographic analysis. Each lesion was composed of many spherical- to ovoid-shaped
tumor nests, which interconnected with each other by narrow
tumor strands, showing features of ginger roots or budding fungi. Small discrete
tumor nests were often present in the peripheral areas of the lesions.
Tumor nests developed around hair follicles and beneath epidermis, but they were never connected with hair follicles or epidermal basement membrane, although occasionally such structures were slightly bent by a pressure from the developing
tumor nests. There was no relationship between
tumor nests and normal sweat glands. Many
tumor nests formed
luminal structures; however, some small
tumor nests did not. Most of the
luminal structures were disconnectedly present. These findings suggest that in each lesion
syringoma may occur in a single focus in the upper dermis without a relationship to the surrounding normal epithelial tissues, develop and partly swell forming lumina, and then the peripheral parts of the
tumor may become discrete. The ratio of [lumen volume/
tumor nest volume] measured by computer stereometry was 0.275 +/- 0.037 (n = 5); this indicates a constant ability to form
luminal structures by
syringoma cells.