Intradiploic epidermoid tumors (cholesteatoma of the skull)

INTRADIPLOIC

EPIDERMOID TUMORS (CHOLESTEATOMA OF THE SKULL)* LEO J. ADELSTEIN, M.D. Los Angeles, California

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PIDERMOIDS, choIesteatomas, pearIy tumors, or CruveiIhier’sl tumeurs perICes are rare neopIasms of ectoderma1 origin. Remak2 in 1854 advanced the thesis that these tumors are embryonic rests resuIting from an incompIete separation of the neura1 from the surface ectoderm. They may occur within the skuI1 or may arise within the dipIoe, causing erosion of the tabIes of the skuI1 and pressure upon the underIying brain. They may arise within the ear and break through into the intracrania1 cavity, or may arise in or upon the brain itseIf. AIthough true epidermoids may occur in connection with the interna ear, most of the masses referred to as choIesteatomas are in reaIity infectious debris consisting of ingrowing squamous epitheIium, secondary to chronic infections in the ear and not true neopIasms. Epidermoids have been IooseIy caIIed choIesteatomas and much discussion has arisen as to the propriety in the use of the term “choIesteatoma,” since it is descriptive onIy of the chemica1 byproduct of the tumor, choIesterin, not invariabIy present. Many years ago epidermoids were distinguished from dermoids on the basis of their embryoIogy. This beIief was supported by evidence that dermoids were the resuIt of mispIaced ectoderma1 ceIIs, occurring from the third to the fifth week of feta1 Iife; whiIe epidermoids represent disturbances to the anIage after the neura1 groove has been cIosed, occurring after the fifth feta1 week and resuIting in the growths found in the meninges, dipIoe and superhcia1 Iayers of the caIvaria. According to Pancoast et al., true in-

tradipIoic epidermoids are very rare but 0ccasionaIIy give rise to neuroIogic symptoms. Since rgzz, when Cushing4 reported a case of his own, some forty-one cases have been recorded in the Iiterature and the surgica1 treatment of this condition has been pIaced on a firm basis. The cIinica1 and x-ray picture which is caused by this tumor is typica and scarceIy to be confused with any other condition. The examination usuaIIy presents a sweIIing on the surface of the skuI1 which may have been present for some years. OrdinariIy there is an associated paIpabIe defect in the norma contour of the skuI1; such defects are generaIIy surrounded by a bony ridge as the edges of the Iesion are frequentIy surrounded by a mass which is soft and Auctuant. If the inner tabIe of the skuI1 has been eroded, transmitted puIsation of the tumor mass may be eIicited. X-ray examination reveaIs a defect in the bones of the skuI1 which may or may not be reguIar. The margins of the defect may be scaIIoped or smooth. The defect itseIf is caused by a tumor which arises within the dipIoe, spreading and eroding the inner and outer tabIes of the skuI1. At operation an encapsuIated cyst is found presenting a whitish caseous mass or a series of whitish rings having the appearance of mother-ofpearI. The capsuIe is extremeIy thin and friabIe and is separated from its bony crater with diffrcuIty. Since the waI1 of the cyst is composed of stratified squamous epitheIium this must be compIeteIy removed in order to prevent recurrence; mere evacuation of the cyst is not sufficient. in 1936 discovered onIy Mahoney5 twenty-three dipIoic epidermoids in a

* From the NeurosurgicaI Service of the Queen of AngeIs Hospital, Los AngeIes, and the Department of Surgery (Neurological) University of Southern CaIifornia SchooI of Medicine. Read before the section of Neuropsychiatry at the 76th AnnuaI Session of the CaIifornia MedicaI Association, May I, I 947.

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series of 142 cases that he couId find in the Iiterature to which he added five cases coIIected in Foerster’s CIinic, in BresIau. MueIIer6 in 1936 was the first to describe an intradipIoic epidermoid and, aside from the three cases described by Bucy,? two by Rowbotham,s four by King9 and ten recentIy described by Rand and Reeves,lO onIy forty-one cases of epidermoids arising between the two tabIes of the skuI1 have been cuIIed from the Iiterature to date. This report is concerned with two cases of epidermoids of the caIvarium in one of which there has been a highIy suggestive history of preceding head injury. CASE

REPORTS

CASE I. This patient had a swelling in the right frontal region since the age of seven years folIowing a head injury. There was a slow increase in size unti1 the age of fourteen years associated with constant headaches and unsightly cosmetic deformity of the forehead. Operation consisted of remova of epidermoid of skuI1 foIIowed by immediate recovery. There was a recurrence three years Iater. Re-operation was carried out with remova including the pericranium and compIete recovery foIlowed. S. N., a fourteen year oId Junior High SchooI student, referred by Dr. M. H. Rabwin, was admitted to the Queen of AngeIs HospitaI, Los AngeIes, July 12, 1944, because of sweIIing in the right side of the forehead. When she was seven years oId, she bumped heads with another chiId, receiving a Iaceration in the right fronta region. She said she remembered this and that she was taken to the Receiving HospitaI where six stitches were used to cIose the cut in her forehead. About six months Iater a bump began to form at the site of the scar. This continued and graduaIIy became Iarger until it finaIIy reached the size of a waInut. There had been moderate headaches present during the past seven years. However, the sweIIing in the right fronta region did not become painful. Examination revealed a perfectly normal appearing girl in good genera1 physical condition. In the right frontal region about midway between the eyebrow and the hair line was a swelling which was quite symmetrical and measured approximately 3 by 3 cm. in diameter. It was eIevated about 1.3 cm. above the surrounding scalp. A fine linear scar ran

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FIG. I. Case I; roentgenogram of skuI1, anteroposterior view showing ‘circumscribed bony defect in the right fronta region characteristic of epidermoid tumor. transverseIy across this eIevation. From the dome of this elevation one received the impression of an indentation, with a sense of fluctuation. The edges were quite firm and crater-like. There were no signs of inflammation and no definite IocaIized tenderness. There were no neurologic signs noted. The deep refIexes were quite sIuggish but about equa1. There were no abnorma1 reffexes. X-rays of the skull (Figs. I, 2 and 3) showed a perfectIy circumscribed bony defect in the right fronta region and outside of the right fronta sinus. It measured approximateIy 2 by 3 cm. in diameter. The margins were cIear cut and appeared to have been caused by a pathoIogic process of a beview- the outer nign nature. In a tangentia1 surface of the structure was elevated above the normal surrounding bone. At operation on July 22, 1944, a semi-circular incision was made in the right frontal region behind the hair Iine, and upon reflecting the mass was scalp Aap downward a soft tumor uncovered in the right frontal area and above the eyebrow, which appeared to be we11 encapsulated and was entireIy beneath the peri-

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2 3 FIG. 2. Case I; roentgenogram, Iateral view, showing cIear-cut, smooth margins of epidermoid tumor. FIG. 3. Case I; roentgenogram, tangential view, indicating the outer surface of the epidermoid to be eievated above the normaf surrounding bon&

cranium. The tumor mass had its bed between both tabIes of the skuII bone. The capsuie of this tumor mass was carefuIIy reffected away from the bony wafls of the fronta bone and the entire contents were removed in toto. The size of this tumor mass was that of a waInut and its consistency was that of brick cheese. The bony bed of the neopIasm was inspected and found to be composed of an inner tabIe of the skuII, which was intact, the dipIoe and the eroded outer tabie. The cyst Iining of this bony bed was carefuIIy removed with a curette; the edges of the outer tabie were smoothed down with a chisel and the opening through the outer tabIe was cIosed by suturing together the pericranium; The scaIp flap was then returned to its norma position and the wound was cIosed in Iayers with interrupted bIack siIk. The patient made a compIete recovery and was discharged from the hospita1 at the end of two weeks. Microscopic examination of the specimen reveaIed abundant non-descript keratin-Iike material arranged in Iayers. The coIor of this materia1 was of a shiny, glistening white. AIso seen was a thin fibrous transparent membrane representing a cyst waI1. Microscopic examination (Fig. 4) of the cyst waI1 reveaIed on the Iining aspect a thin Iayer of we11formed stratified squamous epitheIium, the basement mem-

brane of which was intact. Beneath this epitheIia1 Iayer was a dense, fibrous connecting tissue. There were no gIanduIar eIements. The gross appearance of the contents of the cyst, together with the absence of gIanduIar elements in the cyst waI1, indicated that the cyst contained the accumuIation of years of desquamated epitheIium.

In this case there was the unComment. usua1 history of a head injury which occurred seven years before the patient’s admission to the hospita1. The tumor was Iocated directIy beneath the site of the injury in the right fronta region and was associated with the typicai defect in the skuI1. It was thought that perhaps some epitheIia1 ceIIs were driven down into the bony tissues at the time of this accident, thus giving rise to an epidermoid tumor. This patient returned to her cIasses in schoo1 and apparentIy did very we11 for several years. During the summer of 1947 she again noticed some sweIIing beneath the operative site in the right frontaf region which feIt soft and movabIe and evidentIy was a slow-growing recurrence of the origina tumor mass. X-ray examinaAmerican

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tions of the skuII were made which again showed a circumscribed bony defect in the right fronta region entireIy simiIar to the pictures made some three years previousIy. PhysicaI examination at this time reveaIed no neuroIogic signs. The sweIIing in the right forehead feIt Auctuant with firm edges and was eIevated approximateIy I cm. above the surrounding scaIp. The diagnosis of a recurrent epidermoid tumor of the skuI1 was made. On February 25 1948, utihzing the origina incision behind the hair line in the right fronta region, the scalp Ilap was turned down, unepidermoid tumor covering the recurrent approximately the size of a smalI waInut in the right fronta bone. The pericranium about the tumor mass was incised and the underIying tumor was removed from its bed in the crania1 vauIt. The outer tabIe of the skuI1 was found to be eroded and the base of the tumor was resting in the dipIoe. The bony bed was carefuIIy curetted so that no fragments of the cyst waI1 were Ieft behind. In cIosing this wound the evident mistake made some four years ago was not repeated when the pericranium had been cIosed over the bony defect in the skuI1. At this session the pericranium and the tumor mass were removed together precluding any further growth. The scaIp flap was returned to its correct position and cIosed with muItipIe bIack siIk sutures. The patient made an uneventfu1 recovery and was discharged from the hospita1 five days Iater. To date there has been no sign of any further troubIe. CASE II. This patient compIained of sweIIing in the right parieta1 region during the past seven years associated with severe headaches. There was an increase in size of the tumor mass to that of an orange. Frequent nausea occurred during the past year. The bony defect showed crater formation. The operation consisted of removal of the epidermoid tumor and the patient recovered. N. S., a twenty-seven year oId seamstress, referred by Dr. Waiter HoIIeran, was admitted to the Queen of AngIes HospitaI on January 29, 1947, because of headaches and sweIIing of the scalp in the right parieta1 region. About seven years previousIy the patient had noticed a protuberance in the right side of the head about the size of an oIive, which grew sIowIy unti1 it reached its present size of a smaI1 October,

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FIG. 4. Case I; photomicrograph -of lining membrane of epidermoid tumor showing Iayer of stratified squamous epithelium on which the growth of the tumor depends. orange. At first it was very hard but Iater became soft and doughy. The patient never attached any importance to the tumor and thought that the headaches were due to some aiIment of her eyes, so she went to an optometrist to have gIasses fitted which did not reIieve the condition. About one month before her admission to the hospita1 the patient had frequent periods of nausea and Iost her appetite compIeteIy. There were no other compIaints. She had the usua1 diseases of chiIdhood. At the age of lifteen years she had two convuIsive seizures which did not recur. She had an attack of maIaria eight years previous to her hospital admission. There was no history of any accident or head injuries. Examination reveaIed a paIe appearing, twenty-seven year oId gir1 in good genera1 physical condition. In the right parieta1 region was a sweIIing the size of a tangerine which was quite ffuctuant and soft and which measured approximateIy 5 cm. in its greatest diameter. There were no signs of inffammation and no definite Iocalized tenderness. There were no objective neuroIogic signs noted. X-ray examination (Figs. 5 and 6) revealed a sharpIy circumscribed defect in the right parieta1 bone. There was marked condensation of the margins of this defect. OverIying it was a shadow of the tumor mass. Tangential views

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6 5 FIG. 5. Case II; roentgenogram, latera view, showing choIesteatoma, epidermoid of the cranial vauIt, with circumscribed defect in the right parietal bone. Overlying this defect is ‘shadow of tumor mass. FIG. 6. Case II; roentgenogram, tangentia1 view, showing destruction of the outer tabIe of the parieta1 bone and depression and erosion of the inner tabIe.

FIG. 7. Case II; photomicrograph of epidermoid tumor with intact basement membrane of stratified squamous epitheIium. There is a large amount of desquamated epitheIium present which accumuJated over a number of years.

demonstrated the destruction of the outer tabIe of the parietal bone and depression of the inner tabIe by expansion. The findings were consistent with a new growth invoIving the parieta1 bone and probabIy represented a choIesteatoma. On January 21, 1947, a semi-circuIar flap of the scaIp in the right parietaI area was made, encircling the tumor mass for a distance of approximateIy two-thirds around its circumference. Upon reff ection of this scalp ffap a soft tumor mass was uncovered which seemed to have its origin in the baIIooned-out dipIoe of the right parieta1 bone. An attempt was made carefuIIy to dissect out and encircIe this tumor mass without injuring it. However, at one point the capsule was so thin and friabIe that it broke open, aIIowing much of the cheesy, yeIIowishwhite contents to escape. This was foIIowed by a meticuIous dissection of the entire capsuIe which seemed to fiI1 a crater within the right parieta1 bone, easiIy 4 by 4 cm. in its greatest diameter. At the base of the crater an area of erosion down to the dura was discovered, exposing this membrane for at Ieast 1% cm. The bony defect was carefuIIy curetted to remove every piece of capsuIe Iining and therefore prevent any recurrence. The scalp ffap was then cIosed with muItipIe interrupted black silk American

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Adelstein-Epidermoid sutures and the patient was returned to bed in good condition. She made an uneventful recovery and was discharged from the hospital at the end of ten days. The tumor specimen consisted of a collapsed cystic mass approximateIy 4 cm. in diameter. The waII was thin and fibrous. The Iining surface was smooth and was covered with some adherent gIanduIar gray sebaceous material representing the contents of the cyst. Microscopic examination (Fig. 7) of the cyst waI1 showed on the lining surface a thin layer of essentiaIIy normaI, stratified squamous epithelium the basement membrane of which was intact. The rest of the cyst waI1 was made up of a dense fibrous, partIy hyalinized connective tissue. No derma1 glands or hair foIIicIes were seen in the section. On the outer aspect there was some fatty tissue and a smaI1 amount of striated muscle. Diagnosis: epidermoid cyst. This case represented a typiComment. cal history of a tumor of Iong duration, with a clear cut defect of the skulI recognized in the x-ray studies. Of interest, aIso, was the erosive action of the tumor causing a defect in the inner tabIe of the skuI1 exposing the dura. It is this type of case which might easiIy give rise to convuIsive seizures, particuIarIy when located in the parieta1 region, and which caIIs for diIigent search of the bony crater and the surface of the exposed dura for any bits of lining which couId give rise to recurrence. SUMMARY I. Two epidermoid tumors arising in the dipIoe of the fronta and parieta1 bones of the skuII are described. 2. In Case I the tumor appeared to foIlow cIoseIy a head injury, an etioIogic factor which heretofore has never been given serious consideration. 3. In both cases the patients compIained of constant headaches and there was marked cosmetic deformity. 4. The roentgenographic findings in these lesions are extremeIy characteristic and

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may be recognized preoperativeIy in the majority of instances. 5. The term “cholesteatoma” is confusing and shouId be avoided. The cIassification, primary crania1 and intracrania1 epidermoids, as suggested by Monroe and Wegner,‘l indicates the true type, origin and Iocation of these tumors. 6. AIthough these tumors are benign, the covering membrane of epitheIium is active, and in order to prevent recurrence this Iining membrane must be entireIy removed at operation. One patient reported by Rand and Reeves’” underwent operation four times before fina remova and recovery took pIace. 7. Whenever the inner table of the skul1 has been found to be eroded, a carefu1 search for an intracranial extension should be made. REFERENCES

I. BAILEY, P. Gruveilhier’s “tumeurs perltes.” Surg., Gynec. @ Ok., 3 I: 390, 1920. 2. REMAK, VON R. Ein Beitrag zur Entwickelungsgeschichte der Krebshaften Geschwiilste. Deutscbe Klin., 6: 170, 1854. 3. PANCOAST, HENRY K., PENDERGRASS, EUGENE P. and SCHAEFFER, J. PARSONS. The Head and Neck in Roentgen Diagnosis. SpringfieId, III., Charles C. Thomas. 4. CUSI-~ING, HARVEY. A large epidermal cholesteatoma of the perietotemporal region deforming the left hemisphere without cerebral symptoms. Surg., Gynec. c~ Obst., 34: $57, 1922. 3. MAHONEY, W. Die Epidermoids des zentral Nervensystems. Ztscbr. .f. d. ges. Neural. u. Psycbiat., 153: 416, 1936. 6. MUELLER, JOHANNES. Ober den Feineren Bau and die Formen der krankhaften Geschwiiste. BerIin, 1838. G. Reimer. 7. BUCY, P. C. Intradiploic epidermoid (cholesteatoma) of the skuI1. Arch. Surg., 31: r90, 1935. 8. RO~BOTHAM, G. F. Epidermoids arising in the diploe of the bones of the skull. hit. J. Surg., 26: 506, 1939. 9. KING, JOSEPH E. J. ExtraduraI diploic and intradural epidermoid tumors (cholesteatoma). Ann. Surg., 109: 649, 1939. IO. RAND, CARL W. and REEVES, DAVID L. Dermoid and epidermoid tumors (ChoIesteatomas) of the central nervous system. Arch. Surg., 46: 350-376, ‘943. I I. MUNROE, DONALD and WEGNER, WALTER. Primary cranial and intracranial epidermoids and dermoids. New England J. Med., 2 16: 273, 18, 1937.