The oldest reported mirror hand? The curse of the coal-house frog!

Abstract

Despite being one of the rarest congenital upper limb abnormalities, a wide spectrum of the typical mirror hand has been described in the literature. We report a very interesting case of a new variant of mirror hand presenting in a 78-year-old man. The unique features of the case include the age at diagnosis, the anatomical features present and the acquired function despite no form of reconstructive surgery. KEywORdSLaurin-Sandrow Syndrome -Congenital Abnormalities -Polydactyly Mirror hand is one of the rarest congenital abnormalities affecting the upper limb, with around 70 cases reported in the literature. It is characterised by multiple digits, typically seven in total, with symmetry about the midline, absent thumb, excess carpal bones, absence of radius and duplication of the ulna (ulna dimelia). 1 We describe an unusual case of delayed diagnosis of mirror hand that presented to a hand unit when the patient was aged 78 years. Case historyA 78-year-old man was referred with a suspicious skin lesion on his left shoulder and at the time an abnormal left upper limb was noted. He was on dialysis for chronic renal failure, secondary to polycystic kidney disease. He was born via normal delivery to non-consanguineous parents with no family history of congenital defects. He had two fingers removed from his left hand at 6 months of age but no further investigation or reconstructive surgery had taken place. He was told by his mother that he was born with a hand like a frog as a consequence of a frog having jumped on to her abdomen during pregnancy while collecting coal from a coal-house! On examination, the patient had absence of the thumb with five fingers on his left hand. The most radial digit tended to partial opposition to the other four fingers, similar to the appearance after a pollicisation procedure (Fig 1). He had a range of movement of 15-70º at the wrist and 10-60º at the elbow. The forearm was held in pronation and the left arm was slightly shorter than the right (Fig 2). An arteriovenous fistula was present to facilitate haemodialysis.The patient had good function with both hands. He worked previously as a draftsman for a toy company and in his spare time he was keen on DIY. He had no need to hold a pen in his left hand as he was right hand dominant but holding a knife and fork or other household objects caused no problem. He drove a non-adapted manual car.Radiological evaluation revealed five triphalangeal digits with normal metacarpals and an absent thumb. The radius was absent and two ulna bones were present.