fibrous umbilical polyp
Thursday 17 June 2010
The fibrous umbilical polyp appears to be a distinctive lesion of early childhood with an uncertain pathogenesis.
It has a marked predilection for boys. A series of 19 cases from one institution suggests that it is not rare. They ranged in size from 0.4 to 1.2 cm in diameter.
Fibroblastic cells are plump to elongate with abundant pale pink cytoplasm. Some cells show enlarged stellate nuclei or a ganglion cell appearance. Collagen is sparse to moderate in amount.
The overlying epidermis shows a loss of rete ridges and basket-weave hyperkeratosis. Some cases show focal staining for muscle-specific actin and desmin but no staining for cytokeratin, CD34, S100, or epithelial membrane antigen.