Tertiary yaws

**Definition:** Tertiary yaws develops in <10% of untreated infected individuals after and interval of 5 years or more. The late stage skin lesions are characterised by gummatous nodules with necrotic tissue destruction, followed by debilitating scarring and contracture. Destructive osteitis can result in ulceration of the palate and nasopharynx (‘gangosa’), or bowing of the tibia (sabre shins). Hypertrophic periostitis at periarticular sites can lead to exostosis of the paranasal maxillae (‘goundou’).