Extensive Erosion of the Base of the Skull From a Leptomeningeal Cyst

Abstract

EROSION of the cranial bones from pressure of a leptomeningeal cyst is an uncommon, but not rare, condition. While the majority of such cysts develop after severe trauma to the skull, usually with fracture, there is evidence that congenital abnormalities in the dura and leptomeninges may contribute to their production. Haymaker and Foster1 reported a case in which a large collection of clear, colorless fluid resembling cerebrospinal fluid was found enclosed between the two layers of the dura in the posterior cranial fossa; a small defect was present beneath the tentorium, through which a lobule of the cerebellum was herniated. While their patient gave a history of a fracture of the skull in childhood, the separation of the dural layers and the small subtentorial defect may have been congenital abnormalities which favored development of a cyst in this location.Leptomeningeal cysts have been noted more commonly in the parietal, frontal and occipital regions. In the case to be described a difficult diagnostic and therapeutic problem was presented by the presence of an extensive area of destruction of bone in the floor of the middle cranial fossa. REPORT OF CASEA 28 year old soldier was admitted to an Army general hospital with swelling about the right orbit and temporozygomatic region and with exophthalmos on the same side. One and one-half years before, in North Africa, the patient had received a mild cerebral concussion as a result of an explosion of several large bombs. The following morning he noticed swelling of the right temple and slight exophthalmos. These symptoms persisted for several days and then disappeared, but he continued to have occasional dull, aching pains in the right orbital region, which were relieved by analgesics. One year later he had pneumonia and was hospitalized. It was then noted that there were slight swelling of the temple and slight exophthalmos on the right side, with slight constriction of the right pupil. No other abnormal physical or neurologic signs were present. Roentgenographic examination of the skull revealed a group of cystic-appearing shadows in the right anterior temporal region and in the superior, posterior and lateral 1.

Growing skull fractures (craniocerebral erosion)

“…Except for one, all of our patients were 3 years old or younger. However, several cases of GSF have been reported in adults [11][12][13][14][15][16][17][18].…”

Calcified congenital arachnoid cyst with heterotopic neuroglia in wall.

“…Psammoma bodies are as well scattered in the arachnoid mater as in the glomus choroideum (Shuangshoti and Netsky, 1970). The mode of formation of these calcospherites has been debated, but it has been suggested that they are related to the calcification occurring in degenerated meningocytic whorls (Shuangshoti and Netsky, 1970 (Soule and Whitcomb, 1946;Taveras and Ranshoff, 1953;Starkman et al, 1958). Moreover, an old subdural haematoma may become cystic especially when the large clot is partly absorbed; a subdural cyst with inner and outer neomembranes is formed and may be calcified (Merritt, 1973).…”

“…Cyst of the arachnoid may be congenital or acquired. The acquired arachnoid cysts may occur after cranial trauma, intracranial haemorrhage, or inflammation which result in localised entrapment of the CSF because of adhesions between the pia mater and arachnoid mater, or are related to herniation of the arachnoid mater through dural or cranial defects (Soule and Whitcomb, 1946;Taveras and Ranshoff, 1953;Starkman et al, 1958). Moreover, an old subdural haematoma may become cystic especially when the large clot is partly absorbed; a subdural cyst with inner and outer neomembranes is formed and may be calcified (Merritt, 1973).…”

Chronic Arachnoidal Cysts of the Middle Cranial Fossa and Their Relation to Trauma

“…According to their apparent location in the subdural or subarachnoid spaces and possible aetiology (focal inflammatory processes, congenital anomalies, trauma of meninges), these fluid-filled cavities or cysts, usually walled off by arachnoidal adhesions, have been described by Abbott (1933), Claude (1933), Okonek (1938), Soule and Whitcomb (1946), Taveras and Rouschoff (1953), and Zehnder (1938) under a variety of terms.…”