A case of congenital smooth muscle hamartoma presenting as a human tail

Abstract

A human tail is a rare congenital anomaly, and is characterised by a prominent lesion from the lumbosacrococcygeal region. Human tails are classified into 'true tails' and 'pseudotails'. True tails are comprised of only mesenchymal tissue. They are presumed to be remnants of the embryologic tail. All other lumbosacrococcygeal protrusions are summarized as pseudotails. Congenital smooth muscle hamartoma usually presents as a well-circumscribed, hypertrichotic, hyperpigmented or skin-colored patch or plaque on the trunk or an extremity at birth. Histologically, numerous thick, long, well-defined bundles of smooth muscle fibers are scattered throughout the dermis in various directions. We report a case of congenital smooth muscle hamartoma in a 15-year-old male patient who presented with a tail-like protruding mass accompanied by hypertrichosis and underlying soft tissue deviation.