SYRINGOMA - HISTOCHEMICAL AND ELECTRON MICROSCOPIC STUDIES

[摘要] Histochemical examination of 5 adults with syringoma and 5 human embryos revelaed that amylophos-phorylase, branching enzyme, succinic dehydrogenase, leucine amino-peptidase and PAS [periodic acid Schiff]-positive material, all of which are present in higher concentration in eccrine than in apocrine structures, were strongly reactive in syringoma. Acid phosphatase and indoxyl esterase, both of which show a stronger reaction in apocrine than in eccrine structures, were negative and moderate in reaction in syringoma. Alkaline phosphatase, present in the myoepithelial cells of both eccrine and apocrine glands, was absent in the lesions of syringoma. Syringoma is an organoid tumor differentiating in the direction of eccrine structures. Electron microscopic examination revealed the lumina of syringoma to be bordered by numerous short microvilli. Innumerable small vesicles and pinched-off portions of microvilli were present in the lumina. A number of multivesicular dense bodies were embedded in the periluminal filamentous zone of the inner cells. Multi-vesicular dense bodies and pronounced pinching-off of villi were also found in the embryonic and adult eccrine duct of the lower epidermis. Multivesicular dense bodies were absent in embryonic and adult apocrine structures. It was concluded that the differentiation in syringoma is in the direction of eccrine sweat ducts. The multivesicular dense bodies found in syringoma may represent lysosomes.