Angioadnexocentric nevus.

An association of melanocytic nevus with eccrine glands has been well-documented and well-known as eccrine-centered nevus. Non-giant congenital nevi sometimes contain angiocentric and/or adnexocentric growth of nevus cells. Blood vessels are the most prominent site of nevus cell infiltration and propagation. In our specimen, the second was eccrine ducts. These selective sites of infiltration gave rise to a linear pattern of nevus cell distribution. Upon cursory examination at low magnification, vascular pathologies such as lymphocytic perivasculitis and particularly "coat-sleeve-like" pattern of erythema annulare centrifugum were suggested. S-100 immunostained perivascular and periductal lymphocytoid cells while CD3, 4 and 8 for T cells, and CD20 and 79a for B cells, were all negative. S-100 detected some invasive behavior of nevus cells penetrating into the vascular and ductal walls. However, Ki-67 was negative in all cells, suggesting a benign nature of this lesion. It is postulated that intradermal nevus cells of fetal skin freely migrate through mesenchymal tissue and stop when they hit barriers such as blood vessels and eccrine ducts and propagate in situ. How does this random migration theory explain the blood vessels and eccrine ducts getting the largest share of nevus cells? It is because they are the largest barriers of fetal dermis.