Craniopharyngioma with optic canal enlargement simulating glioma of the optic chiasm

Transcription

1 Craniopharyngioma with optic canal enlargement simulating glioma of the optic chiasm Case report MICHAEL A, BLOCK, M.D., JOHN A. GOREE, M.D., AND JOHN P. JIMENEZ, M.D. Department o] Radiology, Duke University Medical School, Durham, North Carolina 1/ A case of bilateral enlargement of the optic canals by a craniopharyngioma is documented, and the differential diagnosis from optic glioma is discussed. KEY WORDS craniopharyngioma optic canal optic glioma LTHOUGH a craniopharyngioma may extend anteriorly and laterally to cause demineralization and erosion of the optic strut, ~2 this tumor is not recognized as a cause of generalized enlargement of the optic canals. Further, bilateral optic canal enlargement is widely utilized in the diagnosis of optic chiasm glioma2 Although references to "enlargement" of the optic canals with craniopharyngioma have been mentioned in the literature, roentgenographic documentation in these cases is lacking. The purpose of this paper is to report a verified case of craniopharyngioma with bilateral enlargement of the optic canals. Case Report A 9-year-old boy was admitted to this hospital with a 3-year history of episodic headaches, vomiting, and dizziness, plus progressive weakness of the right arm and right face over the past year. One week prior to admission, the child was found to be blind in the left eye. Examination. Although well developed and well nourished, the patient was markedly lethargic. His head circumference was 55 cm, and there was an easily elicited "crackpot sound." Ophthalmological findings included normal right vision with light perception only in the left eye, bilateral optic atrophy, and internal strabismus on the left with a dilated and sluggishly reacting left pupil. There was also a mild right lower facial paresis, slight weakness of the right shoulder and arm, and bilateral positive Babinski signs. Pertinent laboratory findings consisted of abnormally low 17 hydroxyand 17 keto-steroid determinations (0.6 mg/24 hr and 0.5 mg/24 hr respectively). Roentgenographic studies demonstrated retardation of bone growth in the wrists, but normal bone development elsewhere. Skull films showed marked separation of the J. Neurosurg. / Volume 39 / October,

2 Michael A. Block, John A. Goree and John P. Jimenez FIG. 1. Skull film showing that the sutures are separated and the sella turcica enlarged and eroded. There is no suprasellar calcification. cranial sutures, hammered-silver appearance, and an enlarged, eroded sella (Fig. 1 ). No suprasellar calcification was present. There was bilateral enlargement of the optic canals with preservation of the canal walls. The right canal measured 8 mm in its greatest diameter and the left 9 mm (Fig. 2). Pneumoventriculography demonstrated marked hydrocephalus with obstruction of the foramen of Monro and elevation of the left frontal horn by a large suprasellar mass (Fig. 3 ). Operation. A left frontal craniotomy was performed, and a massive craniopharyngioma was found anterior to the optic chiasm. The tumor contained both solid and cystic components. The left optic nerve was markedly stretched to 2 cm in length, and the optic chiasm was 6 to 7 cm in width. A fairly complete removal of the tumor was accomplished. The pathological diagnosis also was craniopharyngioma. Postoperative Course. The patient did well on hormone replacement therapy for 2 89 years and then returned with increasing right hemiparesis and flexion contractures. Repeat roentgenographic examination 3 years after surgery showed optic canals measuring 7 mm in diameter (Fig. 4). The patient died shortly thereafter. FIG. 2. Preoperative skull films showing bilateral enlargement of the optic canals. Left: The right canal (arrows) measured 8 mm in its greatest diameter. Right: The left canal (arrows) measured 9 mm. 524 J. Neurosurg. / Volume 39 / October, 1973

3 Craniopharyngioma simulating glioma of the optic chiasm FIG. 3. Preoperative pneumoventriculograms showing a suprasellar mass obstructing the foramen of Monro and elevating the left frontal horn. Left: Anteroposterior view. Right: Lateral view. Discussion We were unable to find other roentgenographic documentation of enlargement of the optic canals with craniopharyngiomas. Olivecrona TM reported abnormally large optic canals in two adult cases of suprasellar cholesteatoma, a neoplasm which he distinguished from craniopharyngioma. In one case he reported: "Both optic foramina were wider than normal and measured about 6 to 7 mm in diameter." These measurements are equivocal in terms of definite pathological enlargement, particularly in the adult: Olivecrona's other case showed a "right optic foramen very much enlarged and of irregular form with pressure absorption of its margins." No measurements were given nor can they be accurately ascertained from the reproduction of the roentgenogram. FIG. 4. Skull films 3 years after surgery showing that the optic canals have diminished to 7 mm. J. Neurosurg. / Volume 39 / October,

4 Michael A. Block, John A. Goree and John P. Jimenez Farnarier, et al., 5 reported an 8-year-old patient with craniopharyngioma who was stated to have enlarged optic canals but the authors presented neither measurements nor reproductions of the roentgenograms. Lombardi, 8 commenting on the same series as Passerini and Vaghi, 11 reported: "In 13 of the 20 patients in whom the optic foramina were studied, unilateral or bilateral decalcification was observed, in most cases slight, without destruction or interruption of the contours and without widening." Svolos TM recently reported widening of the optic canals in nine cases of craniopharyngioma. All patients were more than 10 years of age and none had separation of the cranial sutures. However, he did not include reproductions of the roentgenograms, measurements, or descriptions of the optic canals. Several authors have described demineralization, erosion, and/or destruction of the sphenoid strut in patients with craniopharyngioma. 'a,4,13 In one of these articles, the authors TM specify that no enlargement of the optic foramen was observed in any of their 30 cases. Merin, et al., a using axial tomography of the optic canals, reported six cases of craniopharyngioma in patients between 9 and 15 years of age who showed "funneling of the intracranial portion of one or both optic canals." A reproduction of the axial tomogram of one of their patients, a 9-yearold boy, showed widening of the posterior part of each canal. Routine roentgenograms of the optic foramina were stated to be normal. Furthermore, in none of their cases of craniopharyngioma did the transverse diameter of the midportion of the optic canals exceed the maximum normal diameter of 7 mm. Although there are many documented causes of "concentric" enlargement of the optic canal, glioma of the optic nerve is the most common cause of this roentgenographic finding. TM Evans, et al., 4 found an enlarged optic foramen in 20 of 24 children with glioma of one optic nerve and in 18 of 27 patients with glioma of the optic chiasm. The latter group included seven patients with bilateral optic canal enlargement. One of the frequently encountered problems in clinical neuro-ophthalmology in childhood is the differential diagnosis of craniopharyngioma and optic glioma. Lombardi, 8 discussing gliomas of the optic chiasm, stated that the alterations seen at pneumoencephalography are those common to suprasellar tumors generally and "if there is no enlargement of the optic foramina there is no certain characteristic to distinguish these tumors from craniopharyngiomas." In our case, this assumption would have suggested the erroneous diagnosis of optic chiasm glioma. Roentgenograms of the optic canals in cases with verified optic chiasm glioma are often identical to the findings in our case of craniopharyngioma. It is important to recognize that although distinct bony margins are a characteristic feature of the foraminal enlargement seen with optic glioma, demineralization of the wails can be caused by a large, probably rapidly expanding tumor. TM The ability to distinguish between the two lesions without biopsy becomes important in view of the favorable results of radiation therapy for optic gliomas as reported by Taveras, et al. 15 In nine of their 34 cases, the diagnosis was made by clinical and radiological methods without the benefit of surgical and pathologic verification. The presence or absence of pathological intracranial calcification can be a significant finding in the differential diagnosis. In 43 cases of craniopharyngioma in children, T6nnis and Friedmann TM found calcification in 84%. However, optic gliomas also have been reported with suprasellar calcification. 7,s In our case, there was no calcification to aid in the diagnosis. Evans, et al., 4 found the presence of the "J"-shaped sellar deformity in 57% of their patients with glioma involving the optic chiasm and noted the absence of enlargement of the pituitary fossa by intracranial optic glioma. The enlarged and eroded sella in our case is therefore not the usual picture in chiasm glioma. Furthermore, Evans, et al. found that three of four children with optic glioma who had endocrine involvement were sexually precocious and had accelerated skeletal maturation, while growth retardation, sexual infantilism, and retarded skeletal maturation were the more common changes secondary to endocrine disturbance in craniopharyngioma. Nevertheless, pitui-.526 J. Neurosurg. / Volume 39 / October, 1973

5 Craniopharyngioma simulating glioma of the optic chiasm tary insufficiency and hypogonadism have been reported in patients with optic gliomas. ~ The etiology of the enlarged optic canals in the current case is unknown. It is uncertain if both the intracranial and intraorbital portions of the canal were involved. Increased intracranial pressure has been reported as causing enlargement of the optic canal. 1 On the other hand, the size of the tumor in our patient, and the "funneling" of the intracranial portions of the optic canals in craniopharyngioma described by others, 9 may indicate that the changes resulted from direct extension of the lesion. As has been reported with optic gliomas, 4 the enlarged optic canals in our patient also became smaller after treatment. Acknowledgment The authors are indebted to Dr. Guy L. Odom, Professor and Chairman of the Division of Neurological Surgery, for his assistance in the preparation of this report. References 1. Dilenge D, Metzger J, Simon J: Le canal optique en neuroradiologie. J Radiol Eleetrol 46: , Dodge HW, Love JG, Craig WM, et al'. Gliomas of the optic nerves. Arch Neurol l'sychiat 79: , Engcset A, Torkildsen A: On changes of the optic canal in cases of intracranial tumor. Acta Radiol (Diagn) (Stockh) 29:57-64, Evans RA, Schwartz JF, Chutorian AM: Radiologic diagnosis in pediatric ophthalmology. Radiol Clin N Amer 1: , Farnarier G, Bonnal J, Monier R: Craniopharyngiome de i'enfant, difficult6 du diagnostic darts les aspects radiologiques inhabituels, r6sultats de l'ablation totale. Rev Oto- Neuro-Ophtal 35: , Huber A: Eye Symptoms in Brain Tumors. St. Louis, C V Mosby, 1971, ed 2, pp 241, Lindgren E, DiChiro G: Suprasellar tumours with calcification. Acta Radiol 36: , Lombardi G: Radiology in Neuro-Ophthalmology. Baltimore, Williams & Wilkins, 1967, pp Merin S, Harwood-Nash DC, Crawford JS: Axial tomography of optic canals in diagnosis of children's eye and optic nerve defects. Am J Ophthal 72 : , Olivecrona H: On suprasellar cholesteatomas. Brain 55: , Passerini A, Vaghi MA: II craniofaringioma: studio radiologico di 82 case. Nunt Radiol 33: , Potter GD, Trokel SL: Optic canal. Radiology of the Skull and Brain. St. Louis, C V Mosby, 1971, pp Schuster G, Westberg G: Gliomas of the optic nerve and chiasm. Aeta l~diol (Diagn) (Stoekh) 6: , Svolos DG: Craniopharyngiomas: a study based on 108 verified cases. Aet~ Clair Scand Suppl 403:1-44, Taveras JM, Mount LA, Wood EH: The value of radiation therapy in the management of glioma of the optic nerves and chiasm. Radiology 66: , TSnnis W, Friedmann G: Das Ri~ntgenbild des,scifi/dels bei intrakranieller Drucksteigerung im Waehstumsalter. Berlin, Springer-Verlag, 1964 Address reprint requests to: John A. Goree, M.D., Department of Radiology, Duke University Medical Center, Durham, North Carolina Neurosurg. / Volume 39 / October,