Dermoid
Cyst of the Scalp: Intracranial
Extension
R. Crawford Aberdeen, l Intracranial dermoid8 are rare and are usually associated with cutaneous scalp lesions. Five hundred forty-two scalp lesions ware treated in a 22-year period, and ware associated with intracranial lesions in three cases. Highrisk cases can be identified by clinical and radiological features, confirmed by a computed tomography scan, and than referred for naurosurgical treatment. o 1990 by W.B. Saunders Company. INDEX WORDS: Cranial dermoid cyst. intracranial axtansion; dumbbell dermoid.
C
RANIAL DERMOID and epidermoid cysts are the most common scalp lesions in children. They are usually excised by pediatric surgeons because they become enlarged, infected, or discharge fluid. Others are excised for cosmetic reasons, or to allay parental anxiety. Because of the association of these cysts with an intracranial extension (“dumbbell dermaid”) that is well documented in neurosurgical literature,ls3 it has been advocated that all cranial dermoids‘should be excised by neurosurgeons4 and that all children with midline lesions should undergo computed tomography (CT) scanning to exclude an intracranial extension5 Therefore, the presentation and management of cranial dermoid cysts at the Royal Hospital for Sick Children, Glasgow, was reviewed with particular regard to these statements. MATERIALS AND METHODS
Case records of at1 patients who presented between 1960 and 1981 with a clinical diagnosis coded under dermoid cyst, sebaceous cyst, or scalp cyst, according to the International Classification of Diseases, were examined. In addition, pathology reports for the same period were examined to identify cases not included in the above. Only lesions occurring on the scalp between eyebrows and occiput were included in the study; external angular dermoids were noted but excluded from further study. RESULTS
Five hundred forty-two scalp lesions were identified; 124 were diagnosed clinically as cranial dermoids, 207 as external angular dermoids, and 211 as other lesions. The mean age of the 124 patients with cranial dermoids was 2.6 years (range, 3 weeks to 12.9 years) and From the Aberdeen Royal Infirmary. Aberdeen, Scotland. Date accepted: November 3.1988. Addies reprint requests to R. Crawfird, MD. Senior Registrar in A&E Medicine, Aberdeen Royal ln$rmary, Foresterhill, Aberdeen, AB ZZB Scotland. o 1990 by W.B. Saunders Company. OOZZ-3468/90/2503-0003$03.00/0 294
Scotland
the female to male ratio was 1S:l. The most common presentation was an asymptomatic swelling present since birth or shortly after birth. The distribution of dermoids on the scalp is shown in Table 1. Twentyeight (22.6%) were in the midline and 19 (15.3%) were infected, or discharged Auid, at some time. Thirtythree skull x-rays were taken, 15 of which (45.5%) showed a bony defect associated with the lesion; all were in the midline. At the time of surgery, an additional 22 patients were noted to have a defect or depression in the bone, six of which were midline, yielding a total of 37 (29.8%) bone defects. In 15 cases (12.1%) a stalk was seen penetrating or attached to the skull. Eighteen (14.5%) were noted specifically to have no communication, and in 70 (56.5%) no comment was made. Ten patients (8.1%) had craniospinal or other congenital abnormalities. The radiological appearances suggested an intracranial extension of the cyst in three cases. This was confirmed by a CT scan and surgery in two cases. Results of the CT scan were negative in the third. In addition, two patients had sinograms performed. Intracranial communication was excluded in one, but confirmed in the other who underwent surgery and had a frontal cerebral abscess evacuated. All these patients had midline lesions. One hundred twenty-one (97.6%) patients had their lesion excised, and 99 (81.8%) specimens were submitted for histological examination. Seventy-one (71.7%) of the lesions examined histologically were confirmed to be dermoid or epidermoid cysts (Table 2). The histological diagnosis of the other 28 lesions is also shown. Two of the three specimens showing ectopic neural tissue were excised from the nasion. DISCUSSION
This review confirms the findings in previous studies of the incidence and distribution of external angular and cranial dermoid cy~ts.“~ However, there is much confusion in the literature because of a failure to differentiate between dermoid and epidermoid cysts.4VgV1’ The main differential diagnosis of cranial dermoids, particularly in midline lesions, is a small cranial meningocele. It is often impossible to differentiate clinically between a small meningocele and a dermoid until x-rays or surgery are performed. This is particularly true if the meningocele has become sequestrated so that it does not bulge upon crying or straining. X-ray film may show the presence of cranium bifidum occulJournal of Pediatric Surgery, Vol
25, No 3
(March), 1990:
pp 294-295
295
CRANIAL DERMOID CYST
Table 1. Distribution site Occipital Parietal
Table 2. Histology of 99 Dermoid8 Sent For Examination
of Cranial Dermoid8
Diagnosis
NO.
No.
(%I
41
(33.1)
Dermoid cyst
46
9
Epidermoid cyst
25
Meningocele
5
Temporal
13
(7.31 tlo.5)
Frontal
15
(12.1)
Ectopic glial and meningeal tissue
3 3
Parieto-Occipital
4
(3.2)
Hamartoma
Anterior Fontanelle
6
(4.81
Meningoancephalocele
2
Dermal sinus
2
Postauricular
18
(14.5)
Nasion
14
(11.3)
lntradermal news
2
4
(3.2)
Pseudorheumatoid nodule
2
Lymph node
2
Miscellaneous
7
Not specified Total
124
(100)
Total
turn or other bony defects, making the diagnosis of meningocele more likely. Intracranial dermoids are rare, accounting for less than 1% of all intracranial tumors.““’ In this series, three patients were found to have an intracranial dermoid in association with their scalp lesion, an incidence of 2.4%. The clinical and radiological features of intracranial extensions of dermoid cysts have been well described. ‘*3They occur most commonly in the posterior fossa and are usually associated with midline lesions. The presence of a sinus or dimple, abnormal hair distribution, or skin thickening should raise the suspicion of an intracranial extension, particularly if the lesion is midline.‘Y3*4 Almost half of the
99
x-rays performed in this study showed bony defects, all associated with midline lesions. The presence of a defect with well-defined sclerotic or scalloped margins is characteristic of an intracranial extension,‘*“W’3 and widening of the sutures may also occur. Such features should lead to referral for neurological assessment and a CT scan. In conclusion, this study confirms that intracranial extensions of cranial dermoid cysts are rare but can be detected by characteristic changes on plain x-ray film taken because of suspicious clinical findings. Confirmation is obtained by a CT scan, and consultation with a neurosurgeon is appropriate.
REFERENCES 1. Logue V, Till K: Posterior fossa dermoid cysts with special reference to intracranial infection. J Nemo1 Neurosurg Psychiatry 151-12, 1952 2. Ohta T, Kajikawa H, Takeuchi J: Congenital Tumours of the Brain, in Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Amsterdam, The Netherlands, 1977, p 61 3. Matson DD: Neurosurgery of Infancy and Childhood (ed 2). Springfield, IL, Thomas, 1969, pp 96-112,607-612 4. Pannell BW, Hendrick EB, Hoffman HJ, et al: Dermoid cysts of the anterior fontanelle. Neurosurgery 3:317-323, 1982 5. Lye RH, Pickard JD: Occipital “sebaceous cysts”-A trap for the unwary. Br J Surg 67:333-334, 1980 6. McAvoy JM, Zuckerbraun L: Dermoid cysts of the head and neck in children. Arch Otolaryngol 102:529-531, 1976 7. New GB, Erich JB: Dermoid cysts of the head and neck. Surg Gynecol Obstet 65:48-55, 1937
8. Taylor BW, Erich JB, Dockerty MB: Dermoids of the head and neck. Minn Med 49:1535-1540, 1966 9. Toglia JU, Netsky MG, Alexander E Jr: Epithelial (epidermoid) tumors of the cranium: Their common nature and pathogenesis. J Neurosurg 23:384-393, 1965 10. Miller NR, Epstein MH: Giant intracranial dermoid cyst: Case report and review of the literature on intracranial dermoids and epidermoids. Can J Neurol Sci 2: 127- 134, 1975 11. Fleming JFR, Botterell EH: Cranial dermoid and epidermoid tumours. Surg Gynecol Obstet 109:403-411, 1959 12. Corkill G, McCulloch GAJ, Tonge RE: Cranial dermal sinus: Value of plain skull x-ray examination and early diagnosis. Med J Aust 1:885-887,1974 13. Guidetti B, Gagliardi FM: Epidermoid and dermoid cysts: Clinical evaluation and late surgical results. J Neurosurg 47:12-18, 1977
Cyst of the Scalp: Intracranial
Extension
R. Crawford Aberdeen, l Intracranial dermoid8 are rare and are usually associated with cutaneous scalp lesions. Five hundred forty-two scalp lesions ware treated in a 22-year period, and ware associated with intracranial lesions in three cases. Highrisk cases can be identified by clinical and radiological features, confirmed by a computed tomography scan, and than referred for naurosurgical treatment. o 1990 by W.B. Saunders Company. INDEX WORDS: Cranial dermoid cyst. intracranial axtansion; dumbbell dermoid.
C
RANIAL DERMOID and epidermoid cysts are the most common scalp lesions in children. They are usually excised by pediatric surgeons because they become enlarged, infected, or discharge fluid. Others are excised for cosmetic reasons, or to allay parental anxiety. Because of the association of these cysts with an intracranial extension (“dumbbell dermaid”) that is well documented in neurosurgical literature,ls3 it has been advocated that all cranial dermoids‘should be excised by neurosurgeons4 and that all children with midline lesions should undergo computed tomography (CT) scanning to exclude an intracranial extension5 Therefore, the presentation and management of cranial dermoid cysts at the Royal Hospital for Sick Children, Glasgow, was reviewed with particular regard to these statements. MATERIALS AND METHODS
Case records of at1 patients who presented between 1960 and 1981 with a clinical diagnosis coded under dermoid cyst, sebaceous cyst, or scalp cyst, according to the International Classification of Diseases, were examined. In addition, pathology reports for the same period were examined to identify cases not included in the above. Only lesions occurring on the scalp between eyebrows and occiput were included in the study; external angular dermoids were noted but excluded from further study. RESULTS
Five hundred forty-two scalp lesions were identified; 124 were diagnosed clinically as cranial dermoids, 207 as external angular dermoids, and 211 as other lesions. The mean age of the 124 patients with cranial dermoids was 2.6 years (range, 3 weeks to 12.9 years) and From the Aberdeen Royal Infirmary. Aberdeen, Scotland. Date accepted: November 3.1988. Addies reprint requests to R. Crawfird, MD. Senior Registrar in A&E Medicine, Aberdeen Royal ln$rmary, Foresterhill, Aberdeen, AB ZZB Scotland. o 1990 by W.B. Saunders Company. OOZZ-3468/90/2503-0003$03.00/0 294
Scotland
the female to male ratio was 1S:l. The most common presentation was an asymptomatic swelling present since birth or shortly after birth. The distribution of dermoids on the scalp is shown in Table 1. Twentyeight (22.6%) were in the midline and 19 (15.3%) were infected, or discharged Auid, at some time. Thirtythree skull x-rays were taken, 15 of which (45.5%) showed a bony defect associated with the lesion; all were in the midline. At the time of surgery, an additional 22 patients were noted to have a defect or depression in the bone, six of which were midline, yielding a total of 37 (29.8%) bone defects. In 15 cases (12.1%) a stalk was seen penetrating or attached to the skull. Eighteen (14.5%) were noted specifically to have no communication, and in 70 (56.5%) no comment was made. Ten patients (8.1%) had craniospinal or other congenital abnormalities. The radiological appearances suggested an intracranial extension of the cyst in three cases. This was confirmed by a CT scan and surgery in two cases. Results of the CT scan were negative in the third. In addition, two patients had sinograms performed. Intracranial communication was excluded in one, but confirmed in the other who underwent surgery and had a frontal cerebral abscess evacuated. All these patients had midline lesions. One hundred twenty-one (97.6%) patients had their lesion excised, and 99 (81.8%) specimens were submitted for histological examination. Seventy-one (71.7%) of the lesions examined histologically were confirmed to be dermoid or epidermoid cysts (Table 2). The histological diagnosis of the other 28 lesions is also shown. Two of the three specimens showing ectopic neural tissue were excised from the nasion. DISCUSSION
This review confirms the findings in previous studies of the incidence and distribution of external angular and cranial dermoid cy~ts.“~ However, there is much confusion in the literature because of a failure to differentiate between dermoid and epidermoid cysts.4VgV1’ The main differential diagnosis of cranial dermoids, particularly in midline lesions, is a small cranial meningocele. It is often impossible to differentiate clinically between a small meningocele and a dermoid until x-rays or surgery are performed. This is particularly true if the meningocele has become sequestrated so that it does not bulge upon crying or straining. X-ray film may show the presence of cranium bifidum occulJournal of Pediatric Surgery, Vol
25, No 3
(March), 1990:
pp 294-295
295
CRANIAL DERMOID CYST
Table 1. Distribution site Occipital Parietal
Table 2. Histology of 99 Dermoid8 Sent For Examination
of Cranial Dermoid8
Diagnosis
NO.
No.
(%I
41
(33.1)
Dermoid cyst
46
9
Epidermoid cyst
25
Meningocele
5
Temporal
13
(7.31 tlo.5)
Frontal
15
(12.1)
Ectopic glial and meningeal tissue
3 3
Parieto-Occipital
4
(3.2)
Hamartoma
Anterior Fontanelle
6
(4.81
Meningoancephalocele
2
Dermal sinus
2
Postauricular
18
(14.5)
Nasion
14
(11.3)
lntradermal news
2
4
(3.2)
Pseudorheumatoid nodule
2
Lymph node
2
Miscellaneous
7
Not specified Total
124
(100)
Total
turn or other bony defects, making the diagnosis of meningocele more likely. Intracranial dermoids are rare, accounting for less than 1% of all intracranial tumors.““’ In this series, three patients were found to have an intracranial dermoid in association with their scalp lesion, an incidence of 2.4%. The clinical and radiological features of intracranial extensions of dermoid cysts have been well described. ‘*3They occur most commonly in the posterior fossa and are usually associated with midline lesions. The presence of a sinus or dimple, abnormal hair distribution, or skin thickening should raise the suspicion of an intracranial extension, particularly if the lesion is midline.‘Y3*4 Almost half of the
99
x-rays performed in this study showed bony defects, all associated with midline lesions. The presence of a defect with well-defined sclerotic or scalloped margins is characteristic of an intracranial extension,‘*“W’3 and widening of the sutures may also occur. Such features should lead to referral for neurological assessment and a CT scan. In conclusion, this study confirms that intracranial extensions of cranial dermoid cysts are rare but can be detected by characteristic changes on plain x-ray film taken because of suspicious clinical findings. Confirmation is obtained by a CT scan, and consultation with a neurosurgeon is appropriate.
REFERENCES 1. Logue V, Till K: Posterior fossa dermoid cysts with special reference to intracranial infection. J Nemo1 Neurosurg Psychiatry 151-12, 1952 2. Ohta T, Kajikawa H, Takeuchi J: Congenital Tumours of the Brain, in Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Amsterdam, The Netherlands, 1977, p 61 3. Matson DD: Neurosurgery of Infancy and Childhood (ed 2). Springfield, IL, Thomas, 1969, pp 96-112,607-612 4. Pannell BW, Hendrick EB, Hoffman HJ, et al: Dermoid cysts of the anterior fontanelle. Neurosurgery 3:317-323, 1982 5. Lye RH, Pickard JD: Occipital “sebaceous cysts”-A trap for the unwary. Br J Surg 67:333-334, 1980 6. McAvoy JM, Zuckerbraun L: Dermoid cysts of the head and neck in children. Arch Otolaryngol 102:529-531, 1976 7. New GB, Erich JB: Dermoid cysts of the head and neck. Surg Gynecol Obstet 65:48-55, 1937
8. Taylor BW, Erich JB, Dockerty MB: Dermoids of the head and neck. Minn Med 49:1535-1540, 1966 9. Toglia JU, Netsky MG, Alexander E Jr: Epithelial (epidermoid) tumors of the cranium: Their common nature and pathogenesis. J Neurosurg 23:384-393, 1965 10. Miller NR, Epstein MH: Giant intracranial dermoid cyst: Case report and review of the literature on intracranial dermoids and epidermoids. Can J Neurol Sci 2: 127- 134, 1975 11. Fleming JFR, Botterell EH: Cranial dermoid and epidermoid tumours. Surg Gynecol Obstet 109:403-411, 1959 12. Corkill G, McCulloch GAJ, Tonge RE: Cranial dermal sinus: Value of plain skull x-ray examination and early diagnosis. Med J Aust 1:885-887,1974 13. Guidetti B, Gagliardi FM: Epidermoid and dermoid cysts: Clinical evaluation and late surgical results. J Neurosurg 47:12-18, 1977
