Iatrogenic intraspinal epidermoid sequestration cysts.

Abstract

Epidermoid sequestration cysts result from the inclusion of ectodermal elements in abnormal locations and represent a form of heterotopia rather than of neoplasia. Growth occurs from the accumulation of epithelial debris within the cyst. The cysts may be congenital or acquired. When congenital, they are related to inclusion of ectodermal elements at the time of closure of the neural groove. Within the spinal canal they may occur as an isolated finding or associated with other congenital defects. Acquired epidermoid cysts may be either post-traumatic or iatrogenic. Epidermoid cysts of the phalanges in carpenters and tailors are examples of the former (10). This paper deals with three examples of iatrogenic epidermoid sequestration cysts of the spinal canal following lumbar puncture or discography. One of these cases has been previously reported by Boyd in 1966 (1); the other 2 are presented for the first time and bring to 18 the number reported in the American and English literature since 1956 (1, 2, 3, 7). Similar cases have appeared in the foreign literature (8). Case I. Present Illness: A 49-year-old housewife was admitted to Porter Memorial Hospital, Denver, Colo., in December 1962 by Dr. Harry R. Boyd, because of pain of increasing severity in the left buttock and leg of one-year duration. Past History: The patient had been previously hospitalized elsewhere in April 1958 for low-back pain. A lumbar myelogram at that time was normal, and the patient was discharged on conservative therapy. The pain persisted, and at rehospitalization in August 1959 lumbar discography at the L-4 and L-5 levels disclosed abnormality at the L-5 level. An orthopedic surgeon performed laminectomy and spinal fusion at the L-4 and L-5 levels. Subsequently a hemolytic Staphylococcus infection developed within the wound. This subsided after a long course of antibiotics and immobilization in a body cast, but the bone graft completely disappeared. Radiographic Findings: Roentgenograms of the lumbar spine showed almost complete obliteration of the L-5-S-1 interspace with narrowing of the interspace below L-4. There was no evidence of congenital abnormality or of active osteomyelitis. A myelogram in December 1962 demonstrated a round defect in the Pantopaque column at the level of the interspace between L-4 and L-5. This had characteristics of an intradural mass lying posteriorly within the spinal canal and showed apparent adherence to the meninges. Operation: Surgery was performed by Dr. Harry R. Boyd. When the dura was opened at the L-4 and L-5 levels, a spherical white mass was found among the nerve roots of the cauda equina. The mass measured approximately 1.5 cm in diameter and was composed of white caseous material characteristic of an epidermoid cyst. This was confirmed by histological examination.