British Journal
of Oral Surgery 14 (1976) 116-l 19
DERMOID
CYST OF THE LOWER D. 6. RULE, B.D.S.,
LIP: A CASE REPORT
F.D.S.,
D.Orth.
Department of Children’s Dentistry, Eastman Dental Hospital, 256 Gray’s Inn Road, London WC1 X 8LD
Summary.A midline dermoid cyst of the lower lip is reported, together with a description of the relevant clinical and pathological features. The embryological basis for the aetiology of the lesion is also discussed. Introduction Certain dermoid cysts, which have been referred to as ectopia (Walter & Israel, 1974), are thought to be developmental in origin, and to arise from the sequestration of ectoderm beneath the surface along the fusion lines of embryonic process. In a series of cases described by New and Erich (1937), a site distribution analysis revealed that these lesions are found relatively infrequently around the head and neck, and furthermore, of the 103 cases reported in this region, only one was found to involve the lower lip. The presence of a dermoid cyst at this latter site would therefore appear to be a uncommon finding. The purpose of this communication is to report the detailed clinical and pathological findings relating to such a developmental dermoid cyst of the lower lip.
Case report The patient, a girl aged three years and ten months of Caucasian origin, first attended the Eastman Dental Hospital 20 October 1974. Her mother stated that although she had been aware of a swelling on the inside of her daughter’s lower lip since the child was aged four months, she had not sought advice previously because the child had never complained of pain, and the lesion had not increased in size until the weeks immediately preceding the visit to hospital. On examination, a midline swelling measuring approximately 15 x 5 mm was found at the base of the lower labial sulcus adjacent to v (Fig. 1). It was of putty like consistency, mobile, and unattached to the overlying mucosa which was of normal colour. The surface of the lesion was grooved by the lower labial fraenum. Radiographic examination of the region revealed a normal bone contour, indicating that the swelling was confined to the soft tissues on the buccal aspect of the mandible. At operation an encapsulated lesion was dissected away from both the overlying mucosa, and the deeper soft tissues, through an incision along the line of the lower labial fraenum. Primary closure of the wound was carried out using interrupted black silk sutures. Healing progressed uneventfully following suture removal, and seven months post-operatively there was no evidence of recurrence. A normal depth of labial sulcus had been re-established, at this stage. (Received
18 February;
accepted
26 April 1976)
DERMOID
FIG. 1. Intra-oral
CYST
photograph
OF
THE
LOWER
LIP
117
of midline swelling at base of labial sulcus.
FIG. 2. Photomicrograph of part of the cyst wall lined with keratinised stratified squamous epithelium and containing both hair follicles and sebaceous glands. (Haematoxylin & Eosin. x 75)
Histopathology The gross specimen measuring 14 x 4 x 3 mm was found to contain yellow pultaceous material which was identified as keratin. Microscopic examination of the lesional tissue showed it to be composed of fibrous tissue lined with keratinised stratified squamous epithelium. Hair follicles and sebaceous glands were found within the fibrous wall (Fig. 2). An extravasation cyst was also found in continuity with the main lesion at a point where part of the keratin contents had escaped into the surrounding tissues (Fig. 3). A positive diagnosis of dermoid cyst was reported.
118
BRITISH
JOURNAL
OF ORAL
SURGERY
FIG. 3. Photomicrograph showing part of lesional wall. The keratin has exuded into the surrounding connective tissue and provoked a marked foreign body reaction. (Haematoxylin & Eosin. x 96)
Discussion The presence of skin appendages within the fibrous wall of the lesional tissue would confirm a diagnosis of dermoid cyst according to the definitions of New and Erich (1937), Meyer (1955) and Walter and Israel (1974). The site of the lesion in the midline, would also point to its being developmental in origin. Although New and Erich (1937) suggested that dermoid cysts of the lower lip arise from enclavement of epithelium during the union of the two mandibular processes, the use by these authors, of the word ‘union’ would suggest that these processes meet and unite in the midline in a manner similar to that by which the palatal processes join; that is to say by fusion following mutual contact between their epithelial surfaces. The currently accepted view is that in the normal situation, the mandibular processes come together as a result of a mechanism variously described as ‘merging’ (Patten, 1961; Little & Jacobsen, 1973), and ‘coalescing’ (Tonge, 1976). Differential growth of the underlying mesoderm leads to a simple smoothing out of the groove between the two processes from below, with no epithelial contact. Patten (1961) has indicated that if the growth of the underlying mesoderm is aberrant to the extent that a mutual contact of the epithelium covering the two mandibular processes does occur, in advance of the obliteration of the separating groove, then epithelium at the base of the groove may become sequestrated beneath the surface. It would clearly be possible for ectoderm entrapped in this manner to give rise to a developmental dermoid cyst containing skin appendages. Acknowledgements I would like to thank Professor C. H. Tonge for his expert guidance with the details of the embryology, and to Mr K. W. Lee for his invaluable help with the interpretation of the histopathology. I am further indebted to Professor G. R. Seward for his encouragement which stimulated my initial interest in this case.
DERMOID
CYST
OF
THE
LOWER
LIP
119
References Little, J. W. & Jacobsen, J. (1973). Journal of Oral Surgery, 31, 188. Meyer, I. (1955). Oral Surgery, Oral Medicine, Oral Pathology, 8, 1149. New, G. B. & Erich, J. B. (1937). Surgery, Gymecology and Obstetrics, 65, 48. Patten, B. M. (1961). The normal development of the facial region. In Congenital Anomalies of the Face and Associated Structures, Edit. S. Pruzansky, p. 41. Springfield, Illinois : Charles C. Thomas. Tonge, C. H. (1976). Personal communication. Walter, J. B. & Israel, M. S. (1974). General Pathology, 4th Ed., p. 361. Edinburgh and London: Churchill Livingstone.
of Oral Surgery 14 (1976) 116-l 19
DERMOID
CYST OF THE LOWER D. 6. RULE, B.D.S.,
LIP: A CASE REPORT
F.D.S.,
D.Orth.
Department of Children’s Dentistry, Eastman Dental Hospital, 256 Gray’s Inn Road, London WC1 X 8LD
Summary.A midline dermoid cyst of the lower lip is reported, together with a description of the relevant clinical and pathological features. The embryological basis for the aetiology of the lesion is also discussed. Introduction Certain dermoid cysts, which have been referred to as ectopia (Walter & Israel, 1974), are thought to be developmental in origin, and to arise from the sequestration of ectoderm beneath the surface along the fusion lines of embryonic process. In a series of cases described by New and Erich (1937), a site distribution analysis revealed that these lesions are found relatively infrequently around the head and neck, and furthermore, of the 103 cases reported in this region, only one was found to involve the lower lip. The presence of a dermoid cyst at this latter site would therefore appear to be a uncommon finding. The purpose of this communication is to report the detailed clinical and pathological findings relating to such a developmental dermoid cyst of the lower lip.
Case report The patient, a girl aged three years and ten months of Caucasian origin, first attended the Eastman Dental Hospital 20 October 1974. Her mother stated that although she had been aware of a swelling on the inside of her daughter’s lower lip since the child was aged four months, she had not sought advice previously because the child had never complained of pain, and the lesion had not increased in size until the weeks immediately preceding the visit to hospital. On examination, a midline swelling measuring approximately 15 x 5 mm was found at the base of the lower labial sulcus adjacent to v (Fig. 1). It was of putty like consistency, mobile, and unattached to the overlying mucosa which was of normal colour. The surface of the lesion was grooved by the lower labial fraenum. Radiographic examination of the region revealed a normal bone contour, indicating that the swelling was confined to the soft tissues on the buccal aspect of the mandible. At operation an encapsulated lesion was dissected away from both the overlying mucosa, and the deeper soft tissues, through an incision along the line of the lower labial fraenum. Primary closure of the wound was carried out using interrupted black silk sutures. Healing progressed uneventfully following suture removal, and seven months post-operatively there was no evidence of recurrence. A normal depth of labial sulcus had been re-established, at this stage. (Received
18 February;
accepted
26 April 1976)
DERMOID
FIG. 1. Intra-oral
CYST
photograph
OF
THE
LOWER
LIP
117
of midline swelling at base of labial sulcus.
FIG. 2. Photomicrograph of part of the cyst wall lined with keratinised stratified squamous epithelium and containing both hair follicles and sebaceous glands. (Haematoxylin & Eosin. x 75)
Histopathology The gross specimen measuring 14 x 4 x 3 mm was found to contain yellow pultaceous material which was identified as keratin. Microscopic examination of the lesional tissue showed it to be composed of fibrous tissue lined with keratinised stratified squamous epithelium. Hair follicles and sebaceous glands were found within the fibrous wall (Fig. 2). An extravasation cyst was also found in continuity with the main lesion at a point where part of the keratin contents had escaped into the surrounding tissues (Fig. 3). A positive diagnosis of dermoid cyst was reported.
118
BRITISH
JOURNAL
OF ORAL
SURGERY
FIG. 3. Photomicrograph showing part of lesional wall. The keratin has exuded into the surrounding connective tissue and provoked a marked foreign body reaction. (Haematoxylin & Eosin. x 96)
Discussion The presence of skin appendages within the fibrous wall of the lesional tissue would confirm a diagnosis of dermoid cyst according to the definitions of New and Erich (1937), Meyer (1955) and Walter and Israel (1974). The site of the lesion in the midline, would also point to its being developmental in origin. Although New and Erich (1937) suggested that dermoid cysts of the lower lip arise from enclavement of epithelium during the union of the two mandibular processes, the use by these authors, of the word ‘union’ would suggest that these processes meet and unite in the midline in a manner similar to that by which the palatal processes join; that is to say by fusion following mutual contact between their epithelial surfaces. The currently accepted view is that in the normal situation, the mandibular processes come together as a result of a mechanism variously described as ‘merging’ (Patten, 1961; Little & Jacobsen, 1973), and ‘coalescing’ (Tonge, 1976). Differential growth of the underlying mesoderm leads to a simple smoothing out of the groove between the two processes from below, with no epithelial contact. Patten (1961) has indicated that if the growth of the underlying mesoderm is aberrant to the extent that a mutual contact of the epithelium covering the two mandibular processes does occur, in advance of the obliteration of the separating groove, then epithelium at the base of the groove may become sequestrated beneath the surface. It would clearly be possible for ectoderm entrapped in this manner to give rise to a developmental dermoid cyst containing skin appendages. Acknowledgements I would like to thank Professor C. H. Tonge for his expert guidance with the details of the embryology, and to Mr K. W. Lee for his invaluable help with the interpretation of the histopathology. I am further indebted to Professor G. R. Seward for his encouragement which stimulated my initial interest in this case.
DERMOID
CYST
OF
THE
LOWER
LIP
119
References Little, J. W. & Jacobsen, J. (1973). Journal of Oral Surgery, 31, 188. Meyer, I. (1955). Oral Surgery, Oral Medicine, Oral Pathology, 8, 1149. New, G. B. & Erich, J. B. (1937). Surgery, Gymecology and Obstetrics, 65, 48. Patten, B. M. (1961). The normal development of the facial region. In Congenital Anomalies of the Face and Associated Structures, Edit. S. Pruzansky, p. 41. Springfield, Illinois : Charles C. Thomas. Tonge, C. H. (1976). Personal communication. Walter, J. B. & Israel, M. S. (1974). General Pathology, 4th Ed., p. 361. Edinburgh and London: Churchill Livingstone.
