Accessory Limb Attached to the Back zyx By Rajiv Chadha, Deepak Bagga, C.J. Malhotra, Ajay Dhar, and Ajay Kumar New zyxwvuts Delhi, India 0 The authors report on a newborn with an accessory malformed leg attached to the back. The limb was associated with a teratomatous mass adjacent to its attachment site. The embryology and nomenclature of this malformation is discussed briefly. Copyright o 1993 by W.B. Saunders Company INDEX WORDS: Accessory leg; teratoma. N ACCESSORY limb attached to the back is an zyxwvu A unusual abnormality, and it appears that reports are few.*-4 It is likely that this condition results from an aborted modified process of twinning. This is the report of a patient in whom the accessory leg was associated with a teratoma adjacent to its attachment over the lumbar spine. CASE REPORT A 2.3-kg full-term boy was born to healthy unrelated parents. There was no history of maternal illness or drug intake during pregnancy and no history of congenital anomalies in the family. At birth an accessory limb was noted; it resembled a deformed leg and was attached to the back in the lumbar region. The leg had a knee joint and a malformed foot with three digits (Fig 1). A flattened bony mass could be palpated at its base, and a rudimentary structure resembling a tiny foot was present above the attachment to the main trunk. A firm solid mass was attached above and to the right of the base of the limb, and a cystic bilobed structure was present below the attachment to the trunk (Fig 2). Just below the cystic mass, there was a depression resembling an anal dimple. The accessory limb lacked movement, and no pulses were palpable. The child also had bilateral equinovarus deformity of the feet. There was no evidence of neurological deficit, and the head circumfer- ence was normal. Plain x-rays showed that the limb had two long bones, the proximal one articulating with a flat bone resembling the ilium. Accessory malformed vertebrae were also present in the lower lumbar region (Fig 3). There was no evidence of spina bifida on the x-rays. Through ultrasonography the following were observed: the mass above and to the right of the base of the limb was solid and of uniform echogenicity, and the bilobed structure below the limb was cystic with no solid contents. Surgery was performed when the baby was 14 days old. An elliptical incision was made around the base of the limb. The limb articulated with a deformed bony mass consisting of a flat bone and two malformed vertebral segments. The mass had a tough fibrous attachment to the paraspinal tissues on the left side of the lumbar spine. No definite neurovascular bundle could be identified. The superiorly situated solid mass was adherent to the base of the limb and was excised along with it. The bilobed cystic structure contained pale yellow fluid and terminated in an attachment on either side of the lumbar spine. After excision of the accessory limb and associated solid and cystic masses, skin flaps from around its base were used to provide adequate wound coverage. The postop- erative period was complicated by mild wound infection, which responded to dressings and antibiotics. Histopathologic examination of the solid mass excised with the Fig 1. Deformed accessoryleg attached to the back. A rudimentary structure resembling a tiny foot is present above the attachment of the main mass to the trunk. limb showed a benign teratoma with cartilage, respiratory and gastrointestinal epithelium. and an abundant connective tissue stroma (Fig 4). DISCUSSION The morphogenesis of this rare malformation is not clear. The limb buds develop from the mesoderm adjacent to the paraxial mesoderm, and a very early zy From the Department of Pediatric Surgery, Lady Hardinge Medical College and Kalawati Saran Children’s Hospital, New Delhi, India. Address reprint requests to Deepak Bagga, MD, S-163, Greater Kailash-Parz I, New Delhi-110048, India. Copyright o I993 by WB. Saunders Company 0022-3468/93/2812-0033$03.00/O JournalofPediatricSurgery, Vol28, No 12 (December), 1993: pp 1615-1617 1615