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An intraoral combined blue naevus
British Journal of Oral and Maxillofacial Surgery (1988) 26, 165-168 0 1988 The British Association of Oral and Maxillofacial Surgeons
AN INTRAORAL G.
COMBINED
BLUE NAEVUS
R. BARKER*, M.%, F.D.s.R.c.s., F.R.C.S.Ed., and P. SLOAN?, Ph.D., B.D.S., IM.R.C.Parh.
“Department of Oral and Maxilla-facial Surgery, Medicine, Manchester University Dental School, Manchester Ml5 6FH
and fDepartment of Oral Higher Cambridge Street,
Summary. A combined blue naevus is described which lay below the epithelial surface of the attached lingual gingiva and the anterior region of the floor of the mouth. There was no visible pigmentation due to the masking effect of the overlying hyperkeratotic mucosa. Histologically the lesion was composed of a mixture of intramucosal naevus cells and dendritic melanocytes typical of a common blue naevus. Prophylactic excision of intraoral naevi is advised.
Introduction
This case is reported because of its unusual clinical and histopathological features in which the characteristic components of both an intramucosal and blue naevus were found to be combined together to form a single lesion. This rare benign cellular combination has been described in the skin (Lever et al., 1983) but there is only one report (Buchner & Hansen 1979) of such a lesion in the oral mucosa, the latter occurring in the palate. There are no reports of pigmented naevi of any type located in the floor of the mouth and Buchner & Hansen (1979 & 1980) found that the most frequent location of intraoral naevi was the hard palate (38%) followed in decreasing order by buccal mucosa, lingual mucosa, gingiva, vermillion border, retromolar area, mucobuccal fold and soft palate. The reported lesion is therefore unusual in both its site and histological pattern. Case report
A 53-year-old white Caucasian male was referred to the Department of Oral and Maxillo-facial Surgery for removal of several carious teeth. On examination a swelling was noted behind the lower incisors which extended from the lingual aspect of the alveolus onto the anterior floor of the mouth. The patient reported that the swelling had been present for some time and had not recently altered in size or consistency. The swelling measured 15 X 10 mm, was firm to palpation with a white stippled surface and with no evidence of superficial pigmentation. The swelling appeared fixed to the underlying tissues but there were no other clinical or radiological abnormalities. An extensive review of the medical history revealed that the patient suffered from polycythaemia rubra vera but was otherwise unremarkable. An incisional biopsy was performed under local analgesia and this showed hyperkeratotic oral mucosa containing nests of typical epithelioid naevus cells within the deep aspect of the reticular lamina propria. Some of these epithelioid cells contained melanin pigment and an initial diagnosis of pigmented naevus was made. Because of the depth of the pigmented cells and the unusual site, a second total excision biopsy was undertaken to include the mucoperiosteum and (Received
3 November
1986; accepted
165
18 June
1987)
166
BRITISH
JOURNAL
OF ORAL
& MAXILLOFACIAL
SURGERY
an adequate margin of apparently normal tissue. The excised specimen measured 10 x 8 x 5 mm and consisted of oral mucosa and underlying connective tissues which were brownish in colour and contained deeply pigmented zones 2-3 mm in diameter. Sections showed hyperkeratosis and thickening of the lamina propria forming fibrous bands. Just within and deep to the reticular lamina propria there were several clusters of typical melanocytic intramucosal naevus cells. The most superficial naevus cells possessed large oval nuclei, abundant cytoplasm and many contained melanin. In the deeper areas the naevus cells were smaller and possessed a scanty cytoplasm devoid of melanin at the light microscope level (Fig. 1). These features were typical of an intramucosal (intradermal) naevus. Lateral and deep to the clusters of naevus cells there were numerous closely packed, elongated melanocytes with long branching processes grouped into irregular bundles (Fig. 2). These bundles extended to the periosteum and into the submucosa of the floor of the mouth and tended to follow the orientation of the adjacent collagen fibres. The melanocytic cells in these areas were densely pigmented and possessed slender dendritic processes containing numerous fine melanin granules (Fig. 2). Occasional, heavily pigmented but more rounded cells, interpreted as melanophages, were scattered between the bundles. These areas of the connective tissue showed the features of a common blue naevus. Thus, overall, the lesion appeared to comprise an association of a blue naevus with an overlying but unusually deeply situated intramucosal naevus, and accordingly a diagnosis of combined naevus was made. Healing was uneventful and the patient has been kept under regular review with no further clinical or radiological signs relevant to the original lesion. Discussion
Melanocytic naevi are benign tumours or hamartomatous lesions which most often appear in adolescence and early adult life, being most frequent in the third decade. A widely variable number of such naevi occur in the skin and on average most Caucasians have 15 (Winkelman & Rocha, 1962; Mackie et al., 1985). Blue
Fig.
1
Fig.
2
Figure I-Photomicrograph of the combined naevus showing clusters of rounded naevus cells which typify the intramucosal naevus lying deep within the reticular lamina propria. (Stained by Haematoxylin & Eosin X 65). Figure 2-Photomicrograph contain abundant pigment
melanocytes which showing areas of the combined naevus rich in dendritic and are similar to those found in common blue naevus. (Stained by Haematoxylin & Eosin X 65).
AN
INTRAORAL
COMBINED
BLUE
NAEVUS
167
naevi occur much less frequently in the skin and are often solitary lesions which exhibit dense bluish pigmentation (Winkelman & Rocha, 1962). Melanocytic and blue naevi are uncommon in the oral mucosa. Buchner & Hansen (1979 & 1980) reviewed 75 cases from the literature together with 32 new cases and found that melanocytic naevi comprised 63.6% and blue naevi 36.4% of intraoral naevi. They suggested that the relatively high frequency of reported cases of intraoral blue naevi may reflect a disproportionate tendency to report such cases, believing them to be rare. However within their consecutive series Buchner & Hansen (1979) found a relative incidence of 25% of blue naevi. We have found 11 acceptable cases of intraoral naevus (excluding lip) in the files of the Oral Pathology Department of the Manchester University Dental School, of which 7 were melanocytic naevi (all intramucosal) and 4 were blue naevi. Although such data suggest that blue naevi have a greater relative frequency in oral mucosa than in skin where the ratio of melanocytic to blue naevi is very high (Wilkinson & Rocha, 1962), it may be that the less conspicuous intramucosal naevi are not always subjected to biopsy. In this regard Buchner & Hansen (1979 & 1980) found that 17% of intraoral naevi were clinically non-pigmented and that 89% of these were of the intramucosal type. With the present case the pigmentation was obscured by the overlying tissues which had developed a frictional hyperkeratosis. The association of a common blue naevus with another type of naevus is found in 1% of naevi in the skin (Gartmann & Muller, 1977). Combined naevi in the dermis tend to consist of a discrete melanocytic naevus which overlies a more deeply sited blue naevus. However, in oral mucosa the lamina propria is heterogeneous in morphology and the submucosa is absent in some sites (Sloan & Soames, 1984). Regional variations may therefore modify the histological features of the various types of naevus. In the present case the naevus was located at the boundary of attached lingual gingiva and floor of mouth mucosa. Although the naevus extended into the floor of mouth submucosa on one aspect, it appeared to be limited by periosteum on its anterior aspect. These anatomical factors may account for a more intimate mixture of cellular components than is usually found in combined naevi in skin. In the present case the overlying hyperkeratosis reinforces the view that oral naevi may be subjected to constant trauma and friction. It is widely accepted that all naevi in skin subjected to recurrent trauma should be prophylactically removed. The true malignant potential of oral naevi has yet to be determined but it is noteworthy that intraoral malignant melanoma, (Sooknundun et al., 1986) although uncommon, has a similar site distribution to that of intraoral naevi. Remnants of benign pigmented naevi are found histologically in 35% of malignant melanomas (Lopransri & Mihm, 1979) and thus it seems wise to advocate prophylactic excision of all intraoral naevi.
References
Buchner, A. & Hansen, L. S. (1979). Pigmented nevi of the oral mucosa: A clinicopathologic study of 32 new cases and review of 7.5 cases from the literature. Part 1, A clinicopathologic study of 32 new cases. Oral Surgery, Oral Medicine & Oral Pathology, 48, 131. Buchner, A. & Hansen, L. S. (1980). Pigmented nevi of the oral mucosa: A clinicopathologic study of 32 new cases and review of 75 cases from the literature. Part 2, Analysis of 107 cases. Oral Surgery, Oral Medicine & Oral Pathology, 49, 55. Gartmann, H. & Muller, H. D. (1977). Uber das gemeinsame Vorkommen von blauen Naevus und Naevaszellnaevus. Zeitschrift fiir Hautkrankheiten, 52, 389. Lever W. F. & Schaumburg-Lever, G. (1983). Histopathology of the Skin, 6th Edition. J. B. Lippincott Company, Philadelphia, pp 681-725.
168
BRITISH
JOURNAL
OF ORAL
& MAXILLOFACIAL
SURGERY
Lopansri. S. & Mihm, M. C. Jnr. (1979). Clinical and pathological correlation of malignant melanoma. Journal of Cutaneous Pathology, 6, 180. Mackie, R. M., English, J., Aitchison, T. C., Fitzsimons, C. P. & Wilson P. (1985). The number and distribution of benign pigmented moles (melanocytic naevi) in a healthy British population. British Journal of Dermatology, 113, 167. Sloan, P. & Soames. J. V. S. (1984). Mcroscopic anatomy and regional organisation of lamina propria. Press. In: The structure and function of oral mucosa. Eds. Meyer, Squier & Gerson, Pergammon Chapter 9. K. & Narayan, P. (1986). Oral malignant Sooknundun, M, Kacker, S. K., Kapila, K., Verma, melanoma. A case report and review of the literature. Journal Laryngology and Otolaryngology, 100, 371. Winkelmann, R. K. & Rocha, G. (1962). The dermal nevus and statistics; an evaluation of 1.200 pigmented lesions. Archives of Dermatology, 86, 310.
AN INTRAORAL G.
COMBINED
BLUE NAEVUS
R. BARKER*, M.%, F.D.s.R.c.s., F.R.C.S.Ed., and P. SLOAN?, Ph.D., B.D.S., IM.R.C.Parh.
“Department of Oral and Maxilla-facial Surgery, Medicine, Manchester University Dental School, Manchester Ml5 6FH
and fDepartment of Oral Higher Cambridge Street,
Summary. A combined blue naevus is described which lay below the epithelial surface of the attached lingual gingiva and the anterior region of the floor of the mouth. There was no visible pigmentation due to the masking effect of the overlying hyperkeratotic mucosa. Histologically the lesion was composed of a mixture of intramucosal naevus cells and dendritic melanocytes typical of a common blue naevus. Prophylactic excision of intraoral naevi is advised.
Introduction
This case is reported because of its unusual clinical and histopathological features in which the characteristic components of both an intramucosal and blue naevus were found to be combined together to form a single lesion. This rare benign cellular combination has been described in the skin (Lever et al., 1983) but there is only one report (Buchner & Hansen 1979) of such a lesion in the oral mucosa, the latter occurring in the palate. There are no reports of pigmented naevi of any type located in the floor of the mouth and Buchner & Hansen (1979 & 1980) found that the most frequent location of intraoral naevi was the hard palate (38%) followed in decreasing order by buccal mucosa, lingual mucosa, gingiva, vermillion border, retromolar area, mucobuccal fold and soft palate. The reported lesion is therefore unusual in both its site and histological pattern. Case report
A 53-year-old white Caucasian male was referred to the Department of Oral and Maxillo-facial Surgery for removal of several carious teeth. On examination a swelling was noted behind the lower incisors which extended from the lingual aspect of the alveolus onto the anterior floor of the mouth. The patient reported that the swelling had been present for some time and had not recently altered in size or consistency. The swelling measured 15 X 10 mm, was firm to palpation with a white stippled surface and with no evidence of superficial pigmentation. The swelling appeared fixed to the underlying tissues but there were no other clinical or radiological abnormalities. An extensive review of the medical history revealed that the patient suffered from polycythaemia rubra vera but was otherwise unremarkable. An incisional biopsy was performed under local analgesia and this showed hyperkeratotic oral mucosa containing nests of typical epithelioid naevus cells within the deep aspect of the reticular lamina propria. Some of these epithelioid cells contained melanin pigment and an initial diagnosis of pigmented naevus was made. Because of the depth of the pigmented cells and the unusual site, a second total excision biopsy was undertaken to include the mucoperiosteum and (Received
3 November
1986; accepted
165
18 June
1987)
166
BRITISH
JOURNAL
OF ORAL
& MAXILLOFACIAL
SURGERY
an adequate margin of apparently normal tissue. The excised specimen measured 10 x 8 x 5 mm and consisted of oral mucosa and underlying connective tissues which were brownish in colour and contained deeply pigmented zones 2-3 mm in diameter. Sections showed hyperkeratosis and thickening of the lamina propria forming fibrous bands. Just within and deep to the reticular lamina propria there were several clusters of typical melanocytic intramucosal naevus cells. The most superficial naevus cells possessed large oval nuclei, abundant cytoplasm and many contained melanin. In the deeper areas the naevus cells were smaller and possessed a scanty cytoplasm devoid of melanin at the light microscope level (Fig. 1). These features were typical of an intramucosal (intradermal) naevus. Lateral and deep to the clusters of naevus cells there were numerous closely packed, elongated melanocytes with long branching processes grouped into irregular bundles (Fig. 2). These bundles extended to the periosteum and into the submucosa of the floor of the mouth and tended to follow the orientation of the adjacent collagen fibres. The melanocytic cells in these areas were densely pigmented and possessed slender dendritic processes containing numerous fine melanin granules (Fig. 2). Occasional, heavily pigmented but more rounded cells, interpreted as melanophages, were scattered between the bundles. These areas of the connective tissue showed the features of a common blue naevus. Thus, overall, the lesion appeared to comprise an association of a blue naevus with an overlying but unusually deeply situated intramucosal naevus, and accordingly a diagnosis of combined naevus was made. Healing was uneventful and the patient has been kept under regular review with no further clinical or radiological signs relevant to the original lesion. Discussion
Melanocytic naevi are benign tumours or hamartomatous lesions which most often appear in adolescence and early adult life, being most frequent in the third decade. A widely variable number of such naevi occur in the skin and on average most Caucasians have 15 (Winkelman & Rocha, 1962; Mackie et al., 1985). Blue
Fig.
1
Fig.
2
Figure I-Photomicrograph of the combined naevus showing clusters of rounded naevus cells which typify the intramucosal naevus lying deep within the reticular lamina propria. (Stained by Haematoxylin & Eosin X 65). Figure 2-Photomicrograph contain abundant pigment
melanocytes which showing areas of the combined naevus rich in dendritic and are similar to those found in common blue naevus. (Stained by Haematoxylin & Eosin X 65).
AN
INTRAORAL
COMBINED
BLUE
NAEVUS
167
naevi occur much less frequently in the skin and are often solitary lesions which exhibit dense bluish pigmentation (Winkelman & Rocha, 1962). Melanocytic and blue naevi are uncommon in the oral mucosa. Buchner & Hansen (1979 & 1980) reviewed 75 cases from the literature together with 32 new cases and found that melanocytic naevi comprised 63.6% and blue naevi 36.4% of intraoral naevi. They suggested that the relatively high frequency of reported cases of intraoral blue naevi may reflect a disproportionate tendency to report such cases, believing them to be rare. However within their consecutive series Buchner & Hansen (1979) found a relative incidence of 25% of blue naevi. We have found 11 acceptable cases of intraoral naevus (excluding lip) in the files of the Oral Pathology Department of the Manchester University Dental School, of which 7 were melanocytic naevi (all intramucosal) and 4 were blue naevi. Although such data suggest that blue naevi have a greater relative frequency in oral mucosa than in skin where the ratio of melanocytic to blue naevi is very high (Wilkinson & Rocha, 1962), it may be that the less conspicuous intramucosal naevi are not always subjected to biopsy. In this regard Buchner & Hansen (1979 & 1980) found that 17% of intraoral naevi were clinically non-pigmented and that 89% of these were of the intramucosal type. With the present case the pigmentation was obscured by the overlying tissues which had developed a frictional hyperkeratosis. The association of a common blue naevus with another type of naevus is found in 1% of naevi in the skin (Gartmann & Muller, 1977). Combined naevi in the dermis tend to consist of a discrete melanocytic naevus which overlies a more deeply sited blue naevus. However, in oral mucosa the lamina propria is heterogeneous in morphology and the submucosa is absent in some sites (Sloan & Soames, 1984). Regional variations may therefore modify the histological features of the various types of naevus. In the present case the naevus was located at the boundary of attached lingual gingiva and floor of mouth mucosa. Although the naevus extended into the floor of mouth submucosa on one aspect, it appeared to be limited by periosteum on its anterior aspect. These anatomical factors may account for a more intimate mixture of cellular components than is usually found in combined naevi in skin. In the present case the overlying hyperkeratosis reinforces the view that oral naevi may be subjected to constant trauma and friction. It is widely accepted that all naevi in skin subjected to recurrent trauma should be prophylactically removed. The true malignant potential of oral naevi has yet to be determined but it is noteworthy that intraoral malignant melanoma, (Sooknundun et al., 1986) although uncommon, has a similar site distribution to that of intraoral naevi. Remnants of benign pigmented naevi are found histologically in 35% of malignant melanomas (Lopransri & Mihm, 1979) and thus it seems wise to advocate prophylactic excision of all intraoral naevi.
References
Buchner, A. & Hansen, L. S. (1979). Pigmented nevi of the oral mucosa: A clinicopathologic study of 32 new cases and review of 7.5 cases from the literature. Part 1, A clinicopathologic study of 32 new cases. Oral Surgery, Oral Medicine & Oral Pathology, 48, 131. Buchner, A. & Hansen, L. S. (1980). Pigmented nevi of the oral mucosa: A clinicopathologic study of 32 new cases and review of 75 cases from the literature. Part 2, Analysis of 107 cases. Oral Surgery, Oral Medicine & Oral Pathology, 49, 55. Gartmann, H. & Muller, H. D. (1977). Uber das gemeinsame Vorkommen von blauen Naevus und Naevaszellnaevus. Zeitschrift fiir Hautkrankheiten, 52, 389. Lever W. F. & Schaumburg-Lever, G. (1983). Histopathology of the Skin, 6th Edition. J. B. Lippincott Company, Philadelphia, pp 681-725.
168
BRITISH
JOURNAL
OF ORAL
& MAXILLOFACIAL
SURGERY
Lopansri. S. & Mihm, M. C. Jnr. (1979). Clinical and pathological correlation of malignant melanoma. Journal of Cutaneous Pathology, 6, 180. Mackie, R. M., English, J., Aitchison, T. C., Fitzsimons, C. P. & Wilson P. (1985). The number and distribution of benign pigmented moles (melanocytic naevi) in a healthy British population. British Journal of Dermatology, 113, 167. Sloan, P. & Soames. J. V. S. (1984). Mcroscopic anatomy and regional organisation of lamina propria. Press. In: The structure and function of oral mucosa. Eds. Meyer, Squier & Gerson, Pergammon Chapter 9. K. & Narayan, P. (1986). Oral malignant Sooknundun, M, Kacker, S. K., Kapila, K., Verma, melanoma. A case report and review of the literature. Journal Laryngology and Otolaryngology, 100, 371. Winkelmann, R. K. & Rocha, G. (1962). The dermal nevus and statistics; an evaluation of 1.200 pigmented lesions. Archives of Dermatology, 86, 310.