Congenital Smooth Muscle Hamartoma Obscuring the Cornea

Abstract

Congenital smooth muscle hamartoma is a benign proliferation of smooth muscle that most commonly presents in the lumbosacral area or proximal extremities. Although exceedingly rare, congenital smooth muscle hamartomas have been reported to occur in ocular structures such as the brow, eyelid, and conjunctival fornix. This case describes an atypical congenital bulbar lesion in a newborn male which obscured the cornea. The lesion, which appeared to originate from the bulbar conjunctiva and/or the limbus, was excised at 5 months of age. Pathologic evaluation was consistent with congenital smooth muscle hamartoma. The authors of this report believe it is the first to describe a patient with a congenital smooth muscle hamartoma of the bulbar conjunctiva/limbus.

Presentation of a Smooth Muscle Hamartoma in the Bulbar Conjunctiva of an Adolescent Boy: A Case Report and Review of Literature

“…This was the first reported case in the bulbar conjunctiva and limbal tissue and was believed to arise from the vascular endothelium in the limbus. 6 Our case represents the fourth recorded presentation of a smooth muscle hamartoma in the conjunctiva and the first presenting in an adolescent individual. In this patient, the lesion was not noted at birth and therefore a congenital etiology was not initially considered.…”

“…3 Conjunctival smooth muscle hamartoma has also previously been reported congenitally in infants 3 times. 4–6…”

“…This was the first reported case in the bulbar conjunctiva and limbal tissue and was believed to arise from the vascular endothelium in the limbus. 6…”

“…Furthermore, it is also possible that the cells arose from the smooth muscle or the capsulopalpebral fascia of the lower eyelid, a pathogenesis that has been postulated in previous literature. 4–6 An argument for this mechanism is the histologic similarity between this lesion and the normal smooth muscle of the eyelid retractor complex. It is important to state that if the lesion originated from these eyelid retractor muscles, then it would be more precise to describe the lesion as a choristoma instead of a hamartoma, the former of which is a proliferation of mature tissue in an abnormal location.…”

“…3 Conjunctival smooth muscle hamartoma has also previously been reported congenitally in infants 3 times. [4][5][6] The first reported congenital conjunctival case presented in a 2-year-old boy with a gray, cystic lesion of the left inferior conjunctival fornix. The lesion was excised and demonstrated irregular bundles of smooth muscle consistent with a diagnosis of a congenital smooth muscle hamartoma.…”