Ultrastructural study of the histogenesis of membranocystic lesions (Nasu) in diabetics.
In order to clarify the histogenesis of membranocystic lesion (MCL) of the skin, 14 biopsies obtained from the shins and feet of diabetics were examined by light and electron microscopy. MCL was observed in 10 of 14 cases, including 7 pigmented pretibial patches (PPP), each a case of diabetic bulla, callus of the knee, and ordinary psoriasis. Ultrastructurally, MCL was characterized by 3 fundamental types of structure: tortuous thick bands composed of well-developed minute tubular structures; shrubbery-like structures in sectional profile consisting of accumulated tiny cysts and microprojections; and thin membranes without minute tubular structures. The small vessels in the dermis and subcutaneous tissue indicated the changes of microangiopathy. Present observations suggested that MCL was derived from subcutaneous fat cells and was displaced into the dermis to be disposed by histiocytes. Circulatory disturbance due to diabetic microangiopathy in the subcutaneous tissue could be one of the contributory factors in the formation of MCL.
D000368:Aged; D001706:Biopsy; D003924:Diabetes Mellitus, Type 2 / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D012867:Skin / Q000648:ultrastructure*