Leontiasis Ossea

Leontiasis is a descriptive term that has been used for at least three different disorders. The first use of the term was for a form of leprosy affecting the facial soft tissues. In this sense, the term has been used since Claudius Galen’s time’ (circa 130–201 ad). Second, the term was used for a type of elephantiasis affecting the soft tissues of the head and neck. Third, leontiasis ossea, was the name given by Rudolf Virchow (1821–1902) to a condition causing hyperostosis of the skull. He felt that the overgrowth of bone matched the elephantiasis of soft tissue and ‘he decided to call these cases leontiasis ossea, not because the bone disease produced a leonine appearance, but because he considered it to be analogous to a disease of the soft parts which did.’ ² Virchow’s description is based on the study of several skulls, the first one originally described by Marcello Malpighi (1628–1694) in the Opera Posthuma in 1700 ² . Another case known to Virchow, the first with a clinical history, is shown in Figure 2. Today, we use the term leontiasis ossea primarily to describe the skull changes due to the condition known as fibrous dysplasia (Figure 1). Whether any of the cases studied by Virchow were actually due to fibrous dysplasia is not known. Disorders other than fibrous dysplasia also give rise to leonine changes in facial bones. Among them are Paget’s, renal osteodystrophy and reactive inflammatory bone disease ³ . Figure 1 Anteroposterior (A) and lateral (B) views of the skull showing extreme deformation due to fibrous dysplasia. Case courtesy of Dr Anne Brower https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003076568/34c29fd5-5662-4e8f-b58c-badd7fa5d724/content/fig48_1_B.jpg"/> Figure 2 Drawing of Fourcade’s case. The patient was his son who died at age 45 in 1767. Reprinted from Knaggs<xref ref-type="bibr" rid="ref48_2"> ² </xref>. Leontiasis Ossea. <italic>Br. J. Surg.,</italic> 1923, 11, 347–79 with permission of Blackwell Science Ltd, the publisher https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003076568/34c29fd5-5662-4e8f-b58c-badd7fa5d724/content/fig48_2_B.jpg"/>