Possible premalignant character of oral lichen planus
A. B. E. Voute', W. F. B. de Jong\ E. A. J. M. Schulten', G. B. Snow^ and I. van der Waal^ Departments of 'Oral and f^axillofacial Surgery and Oral Pathology. Academic Centre for Dentistry Amsterdam (ACTA). 'Otorhinolaryngology. Free University Hospital. Amsterdam. The Netherlands.
the Amsterdam experience VoCite ABE, de Jong WFB, Schulten EAJM, Snow GB, van der Waal I: Possible premalignant character of oral lichen planus: the Amsterdam experience. J Oral Pathol Med 1992; 21: 326 9. In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, is reported with regard to the possible premalignant character of oral lichen planus. The study consists of two parts: 1) the follow-up of 113 patients with histopathologically proven oral lichen planus, and 2) a search for lichen planus in 727 patients who have been admitted for oral cancer. Three patients with histopathologically proven lichen planus developed a squamous eell carcinoma in an average follow-up period of 7 yr. In the 727 patients with oral cancer, two additional patients with the simultaneous occurrence of oral lichen planus were observed. Our experience gives some but not very strong support to the hypothesis that oral lichen planus is a premalignant condition.
For a long time lichen planus of the oriil mucosa has been considered a benign condition. In the seventies, however, the issue has been raised of a possible premalignant nature. In the I97X report by the World Health Organisation it was stated: "While a number of reports have referred to cancer in the erosive or atrophic types of lichen planus, there remains considerable uncertainty about the frequency of this occurrence". Ever since, the literature contains a growing number of papers that suggest a premalignant character of oral lichen planus. The percentage of reported malignant transformation varies from 0.3 to three (1). In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, will he reported. This study consists of two parts: 1) the followup of patients with oral lichen planus, and 2) a .search for lichen planus in patients who have been admitted for oral
Key words: mouth, diseases: oral cancer: oral lichen planus; premalignant I. van der Waal. Free University Hospital. Department of Oral and Maxillotacial Surgery and Oral Pathology. De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands Accepted for publication February 1, 1992
1, 1991, 176 patients could be retrieved in whom with a reasonable degree of certainty the diagnosis of oral lichen planus, being confirmed by histopathologic examination, was made. The clinical records of these patients have been studied with regard to the possible development of oral cancer. For those patients who had been lost for follow-up , recalls have been arranged, resulting in a total number of 113 patients that have been seen for follow-up. The mean follow-up of these patients was 7.8 yr (range: 0.5-21) (Table 1). In 727 patients with oral cancer, observed in the same period as mentioned before, the simultaneous or previous presence of oral lichen planus has been searched for in the records. This group consisted of 465 men and 262 wotnen, the mean age being 63, ranging from 23 to 99 yr.
Results Of the 113 patients who were available for follow-up, malignant changes of the oral mucosa had taken place in three of them (2.6'!^i) in a tnean follow-up period of seven years. The data of these three patients are summarized in Table 2. In the group of 727 patients with oral squamous cell carcinoma the synchronous presence of lichen planus had been ob.served in {\\c patients (0.7'^) (Table 3), including the three patients mentioned in Table 2. In two other patients the history was suggestive of the presenee of previous oral lichen planus. In retrospect, however, that diagnosis was proven to be wrong (Table 4). In none of the patients with oral caneer, lichen planus of the oral mucosa developed during follow-up after treatment for their malignancy.
Table I. Demographic data of 113 patic-nts with histopathologically proven oral lichen planus
Material and methods
Gender
In a search of the files of the Department of Oral and Maxillofacial Surgery and Oral Pathology of the Free University Hospital, Amsterdam, in the period between January 1, 1970 and January
Women Men Total *' in years
No. of patients
Mean age at onset (range)*
Mean duration of follow-up (range)*
79
49.2 (14.7 79.5) 46.1 (10.6 70.0)
S.2 (0.5 21) 6.9 (1.0 19)
m
48.3 (10.6 79.5)
7.x (0.5 22)
Premalignant character of oral lichen plartus Table 2. Malignant transformation in three patients with oral lichen planus
327
Patient 1
Patient 2
Gender
Woman
Woman
Age at onset (in yr)
45
64
Criteria on which the diagnosis of lichen planus was made
Clinical, histopathologic and immunofluorescence aspects
Clinical aspects only
Clinical aspect
Erosive type (crythroplakic lesion)
Erosive type (erythroplakia?)
by histopathologie examination of the biopsy. In general, performance of a biopsy is not mandatory for the diagnosis of oral lichen planus. since in many instances the diagnosis ean be reliably made on elinieal features only. Just for the diseussion we like to aeeept the prevalence found in AXELL'S study among an adult Swedish population (2). In that study the prevalenee of oral liehen planus has been established at 1.89%. It is well recognized that both the clinical and histopathologic eriteria of oral lichen planus leave room for some subjectivity in the interpretation. Especially the plaque type and also the erosive type of liehen planus may at sotne times be dilTicult to distinguish elinieally from the various manifestations of hotnogeneous and non-homogeneous leukoplakia. The specificity of the histopathologic diagnosis of oral lichen planus seems to be very mueh in aeeordanee with that of the elinieal diagnosis. The Haws in the clinical and histopathologic criteria of oral liehen planus may explain some of the discrepancies both in the prevalenee of oral lichen planus and the reported rate of malignant transformation. In all of our three patients in whom malignant transfonnation took place (Table 2). there is room for diseussion about the eorreetness of the original diagnosis of liehen planus, both from a elinieal and a histopathologie point of view. In the first patient we may have actually been dealing with ehronie diseoid lupus erythematosus instead of lichen planus (Fig. 1). In tbe second patient a transfonnation seem to have taken plaee from lichen planus into leukoplakia and. finally, into verrueous careinoma (Fig. 2). In the third patient, there retnains the possibility of the synehronous presence of liehen planus and erythroplakia or an erythroplakie lesion, as has been discribed by HOLM-
13 months
STRUP & PlNDBORG (3).
Patient 1
Patient 2
Patient 3
Gender
Man
Woman
Woman
Age at onset (in yr)
48
65
58
Criteria on which the Clinical and histopathologic aspects diagnosis of lichen planus was made
Clinical, histopatho- Clinical, histopathologic and immunoflu- logic and immunotluorescence aspects orescence aspects
Type of lichen planus Erosive type
Reticular type
Erosive type (or associated erythroplakia?)
Time interval in which squamous cell carcinoma occurred (in yr)
7
5
9
Tobacco habits
None
None
None
Cancer site
Lower lip
Dorsum of the tongue Buccal tnucosa and buccal mucosa
Table 3. Patients with oral squamous cell carcinoma and a pasi1 or present history of oral lichen planus (excluding the patients from Table 2). Patient 1
Patient 2
Gender
Man
Womati
Age at onset (in yr)
76
71
Criteria on which the diagnosis of lichen planus was made
Clinical aspects
Clinical aspects
Type of lichen planus
Reticular type
Plaque type
Tobacco habits
25 cigarets per day
None
Cancer site
Tongue
Lower alveolar ridge
Table 4. Patients with oral cancer with1 an incorrect previotis diagnosis of lichen planus
5 months Time interval between incorrect diagnosis of lichen planus and diagnosis of oral squamous cell carcinoma Tobacco habits
None
Gave up smoking 20 years ago
Cancer site
Lower lip
Buccal mucosa
Discussion No prevalence or ineidenee studies on oral liehen planus are available for The Netherlands. Of eourse. it is not possible to establish sueh figures on the basis of the number of patients who
have been referred to a Department of Oral and Maxillofaeial Surgery and Oral Pathology. Besides, there is another bias in the present study, sinee only those patients have been ineluded in the follow-up study in whom the diagnosis oral liehen planus was supported
If the initial diagnosis of oral liehen planus has been correetly made in all our three eases, then the statement eould be made that 2.6% of patients with histologically proven oral lichen planus showed malignant transformation in an average time of 7 yr after establishment of the original diagnosis. Beeause of the referral bias this pereentage cannot be accepted as being representative of the average malignant transformatioti rate of oral lieheti planus. Furthertnore. malignant transformation may have taken plaee in one or more of the patients who had been lost
328
VouTi: ei al.
Fig. I. Patient I. A) mucosal lesion of lower lip. clinically and histopathologicully diagno.scd as "compalihic with lichen planus". li) 9 months later another erosive lesion developed. No biopsy has been taken, nor any trealment has been instituted. C) 7 yr alter A was taken, a well differentiated squamous cell careinoma developed.
for follow-up. Beeau.se of tbe low migration rate of the Dutch population, such event is rather unlikely to have occurred without notification. Assuming that the prevalenee of oral liehen planus in adults found by A.xixi. (2) (1.89%) is valid for The Netherlands as well, one could expect that 13 of the 727 patients with oral squamous cell carcinoma would have had either a past or present history of lichen planus. while this aetually has been the ease in five patients (0.7%). In patient 2 of Table 3 also Cuwf/zV/w-associated lesions were observed. In fact, a biopsy of tbe lesion of the dorsum of the tongue, taken 4 yr later, was eonsistent witb the diagnosis of ehronie hyperplastic candidiasis. In retrospect, this patient may. therefore, erroneously have been included in Table 3. In retrospect, it is difficult to understand from the elinieal aspects, that in the two patients mentioned in Table 4 an initial diagnosis of oral lichen planus has been made. In one of these two patients a biopsy has been taken. In retrospect, this biopsy did show signs of at least slight epithelial dysplasia. possibly qualifying for the label of lichenoid
dysplasia. as propo.sed by KRtirciiKOKF & Eisi:NHi:R(i (4). As a result, tbe correctness of the initial bistopathologic diagnosis "compatible with oral lichen planus" is at least questionable. In the other patient of this group, it remains somewhat unexplainable why the elinical diagnosis of oral lichen planus was made initially instead of erythroplakia. Others have reported similar experiences (5). In a review of tbe literature of 220 cases of reported malignant transformation occurring in oral lichen planus. K R U K iiKoii- (•/ al. only found 15 ca.ses tbat satisfied tbeir criteria (6). In a follow-up study of 225 eases of oral liehen planus one careinoma (O.S%) developed after an observation period of 5 yr (7). In another follow-up study of 611 patients, probably including the latter group of 225 patients, nine (1.5'Mi) patients developed oral squamous eell earcinoma during follow-up, tbat ranged from 4.9 to 24 yr (8). In yet another follow-up study of oral lichen planus reported from India three carcinomas (0.4'y!.) developed in 722 patients after a mean observation period of 5.1 yr (9). In a prospeetive study in San Francisco.
consisting of 570 patients, malignant transformation occurred in 1.2% in a mean time of 3.4 yr after the onset of liehen planus (10). There is a discrepancy with regard to tbe finding of high pecentages of epithelial dysplasia in oral lichen planus. varying from 25 51"/ii and tbe extremely low malignant transformation rate ( I I . 12). In summary, our experience gives some but not convincing support to the hypothesis that oral lichen planus is a premalignant condition. From a praetieal point of view we feel somewhat reluctant to routinely inform each patient witb oral lieben planus about the possible premalignant character of their lesions. In general, we advise bi-annual dental ebeek-up, including thorough inspeetion of tbe oral mucosa.
References 1. KAI'I.AN K . HARNI.S 1,. Oral lichen planus and squatiious carcinoma. .-Irch Otolaryttgol 19X5; I I I : 543 7. 2. Ax(:i.i, T. HOLMSTRUP P. KRAMI:R
IRH.
PiNDitoRci JJ, SHI:AR M . International seminar on oral leukoplakia and assciciated lesions related lo tobacco habits.
PrenialiiiiHmt characler of oral lichen phmiis 329
Fig. 2. Patient 2. AI plaque lype lichen planus of dorsal surface of tongue. B) diagnosis of lichen planus was further supported by clinical aspect c~)f left (and right) buccal mucosa and biopsy from this site. Clinically, there seems to be overlap of lichen planus and leukoplakia. C) 5 yr after initial visit of patient a verrucous carcinoma of dorsal surface of tongue developed.
Cotnnniniiy Dent Ontl Epidemiol 19S4: 12: 145 54. 3.
Hoi.M.srRiip
P,
PiNDHORc;
.U.
Fryth-
roplakic lesions in relation to oral lichen planus. Ada Dermatovener 1979: 59: 77 84. 4. KRtiTCliKoi I DJ. liisiNiii RCi I:. I.ichcnoid dysplasia: a distinct histopathologic entity. Oral Surg Oral Med Oral Pathol 1985: 60: yi)V. 15. 5. LovAS JGL. HARSANYI BB. Ill CII:NI:II)V
AK. Oral lichenoid dysplasia: A clinicopathologic analysis. Oral Surg Oral Med Oral Pathol 1989: 68: 57 63. 6. KRIUCIIKOI I DJ, Cirn,i:R L. LASKOWSKI
S. Oral lichen planus: The evidence regarding potential malignant Iranslormal^ion. ./ Oral Pathol 1978: 7: 1 7. I'M I iNci HJ Cancer development in oral lichen planus. .-In/i Dermaiol 1973: 108: 667 9. ii .1.1. Malignant development of lichen plaiuis-alTected oral mucosa. J Oral Pathol 1988: 17: 219 25. MURTI PR. DAITARV DK. BitONSi i RB.
10 SlI VIRMAN S. GORSKY M . LoZADA-NuR F. .\ prospective follow-up study of 570 patiens with oral lichen planus: Persistancc. remission and malignant association. Oral Surg Oral Med Oral Pathol 1985: 60: 30 4. II JoNti Di: W I B . Al BRiicHT M. BAN6CZY J. WAAI. VAN DKR I. Epithelial dysplasia in oral lichen planus. .\ preliminary report o f a Dutch-Hungarian study of 100 cases. Int J Oral Surg 1984: L^: 221 5.
GUPTA PC. MKHTA F S . PiNtiiumc; JJ.
12. OiniKOYA O. GALLAGHER G . SHKLAR G .
Malignant potential of oral lichen planus: Observation in 722 patients from India. ./ Oral Paihol 1986: 15: 71 7.
A hislologic study of epithelial dysplasia in oral lichen planus. .Arch Dermatol 1985: 12L 1132-6.
P. THORN J.I. RiNnti.vi J.
A. B. E. Voute', W. F. B. de Jong\ E. A. J. M. Schulten', G. B. Snow^ and I. van der Waal^ Departments of 'Oral and f^axillofacial Surgery and Oral Pathology. Academic Centre for Dentistry Amsterdam (ACTA). 'Otorhinolaryngology. Free University Hospital. Amsterdam. The Netherlands.
the Amsterdam experience VoCite ABE, de Jong WFB, Schulten EAJM, Snow GB, van der Waal I: Possible premalignant character of oral lichen planus: the Amsterdam experience. J Oral Pathol Med 1992; 21: 326 9. In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, is reported with regard to the possible premalignant character of oral lichen planus. The study consists of two parts: 1) the follow-up of 113 patients with histopathologically proven oral lichen planus, and 2) a search for lichen planus in 727 patients who have been admitted for oral cancer. Three patients with histopathologically proven lichen planus developed a squamous eell carcinoma in an average follow-up period of 7 yr. In the 727 patients with oral cancer, two additional patients with the simultaneous occurrence of oral lichen planus were observed. Our experience gives some but not very strong support to the hypothesis that oral lichen planus is a premalignant condition.
For a long time lichen planus of the oriil mucosa has been considered a benign condition. In the seventies, however, the issue has been raised of a possible premalignant nature. In the I97X report by the World Health Organisation it was stated: "While a number of reports have referred to cancer in the erosive or atrophic types of lichen planus, there remains considerable uncertainty about the frequency of this occurrence". Ever since, the literature contains a growing number of papers that suggest a premalignant character of oral lichen planus. The percentage of reported malignant transformation varies from 0.3 to three (1). In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, will he reported. This study consists of two parts: 1) the followup of patients with oral lichen planus, and 2) a .search for lichen planus in patients who have been admitted for oral
Key words: mouth, diseases: oral cancer: oral lichen planus; premalignant I. van der Waal. Free University Hospital. Department of Oral and Maxillotacial Surgery and Oral Pathology. De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands Accepted for publication February 1, 1992
1, 1991, 176 patients could be retrieved in whom with a reasonable degree of certainty the diagnosis of oral lichen planus, being confirmed by histopathologic examination, was made. The clinical records of these patients have been studied with regard to the possible development of oral cancer. For those patients who had been lost for follow-up , recalls have been arranged, resulting in a total number of 113 patients that have been seen for follow-up. The mean follow-up of these patients was 7.8 yr (range: 0.5-21) (Table 1). In 727 patients with oral cancer, observed in the same period as mentioned before, the simultaneous or previous presence of oral lichen planus has been searched for in the records. This group consisted of 465 men and 262 wotnen, the mean age being 63, ranging from 23 to 99 yr.
Results Of the 113 patients who were available for follow-up, malignant changes of the oral mucosa had taken place in three of them (2.6'!^i) in a tnean follow-up period of seven years. The data of these three patients are summarized in Table 2. In the group of 727 patients with oral squamous cell carcinoma the synchronous presence of lichen planus had been ob.served in {\\c patients (0.7'^) (Table 3), including the three patients mentioned in Table 2. In two other patients the history was suggestive of the presenee of previous oral lichen planus. In retrospect, however, that diagnosis was proven to be wrong (Table 4). In none of the patients with oral caneer, lichen planus of the oral mucosa developed during follow-up after treatment for their malignancy.
Table I. Demographic data of 113 patic-nts with histopathologically proven oral lichen planus
Material and methods
Gender
In a search of the files of the Department of Oral and Maxillofacial Surgery and Oral Pathology of the Free University Hospital, Amsterdam, in the period between January 1, 1970 and January
Women Men Total *' in years
No. of patients
Mean age at onset (range)*
Mean duration of follow-up (range)*
79
49.2 (14.7 79.5) 46.1 (10.6 70.0)
S.2 (0.5 21) 6.9 (1.0 19)
m
48.3 (10.6 79.5)
7.x (0.5 22)
Premalignant character of oral lichen plartus Table 2. Malignant transformation in three patients with oral lichen planus
327
Patient 1
Patient 2
Gender
Woman
Woman
Age at onset (in yr)
45
64
Criteria on which the diagnosis of lichen planus was made
Clinical, histopathologic and immunofluorescence aspects
Clinical aspects only
Clinical aspect
Erosive type (crythroplakic lesion)
Erosive type (erythroplakia?)
by histopathologie examination of the biopsy. In general, performance of a biopsy is not mandatory for the diagnosis of oral lichen planus. since in many instances the diagnosis ean be reliably made on elinieal features only. Just for the diseussion we like to aeeept the prevalence found in AXELL'S study among an adult Swedish population (2). In that study the prevalenee of oral liehen planus has been established at 1.89%. It is well recognized that both the clinical and histopathologic eriteria of oral lichen planus leave room for some subjectivity in the interpretation. Especially the plaque type and also the erosive type of liehen planus may at sotne times be dilTicult to distinguish elinieally from the various manifestations of hotnogeneous and non-homogeneous leukoplakia. The specificity of the histopathologic diagnosis of oral lichen planus seems to be very mueh in aeeordanee with that of the elinieal diagnosis. The Haws in the clinical and histopathologic criteria of oral liehen planus may explain some of the discrepancies both in the prevalenee of oral lichen planus and the reported rate of malignant transformation. In all of our three patients in whom malignant transfonnation took place (Table 2). there is room for diseussion about the eorreetness of the original diagnosis of liehen planus, both from a elinieal and a histopathologie point of view. In the first patient we may have actually been dealing with ehronie diseoid lupus erythematosus instead of lichen planus (Fig. 1). In tbe second patient a transfonnation seem to have taken plaee from lichen planus into leukoplakia and. finally, into verrueous careinoma (Fig. 2). In the third patient, there retnains the possibility of the synehronous presence of liehen planus and erythroplakia or an erythroplakie lesion, as has been discribed by HOLM-
13 months
STRUP & PlNDBORG (3).
Patient 1
Patient 2
Patient 3
Gender
Man
Woman
Woman
Age at onset (in yr)
48
65
58
Criteria on which the Clinical and histopathologic aspects diagnosis of lichen planus was made
Clinical, histopatho- Clinical, histopathologic and immunoflu- logic and immunotluorescence aspects orescence aspects
Type of lichen planus Erosive type
Reticular type
Erosive type (or associated erythroplakia?)
Time interval in which squamous cell carcinoma occurred (in yr)
7
5
9
Tobacco habits
None
None
None
Cancer site
Lower lip
Dorsum of the tongue Buccal tnucosa and buccal mucosa
Table 3. Patients with oral squamous cell carcinoma and a pasi1 or present history of oral lichen planus (excluding the patients from Table 2). Patient 1
Patient 2
Gender
Man
Womati
Age at onset (in yr)
76
71
Criteria on which the diagnosis of lichen planus was made
Clinical aspects
Clinical aspects
Type of lichen planus
Reticular type
Plaque type
Tobacco habits
25 cigarets per day
None
Cancer site
Tongue
Lower alveolar ridge
Table 4. Patients with oral cancer with1 an incorrect previotis diagnosis of lichen planus
5 months Time interval between incorrect diagnosis of lichen planus and diagnosis of oral squamous cell carcinoma Tobacco habits
None
Gave up smoking 20 years ago
Cancer site
Lower lip
Buccal mucosa
Discussion No prevalence or ineidenee studies on oral liehen planus are available for The Netherlands. Of eourse. it is not possible to establish sueh figures on the basis of the number of patients who
have been referred to a Department of Oral and Maxillofaeial Surgery and Oral Pathology. Besides, there is another bias in the present study, sinee only those patients have been ineluded in the follow-up study in whom the diagnosis oral liehen planus was supported
If the initial diagnosis of oral liehen planus has been correetly made in all our three eases, then the statement eould be made that 2.6% of patients with histologically proven oral lichen planus showed malignant transformation in an average time of 7 yr after establishment of the original diagnosis. Beeause of the referral bias this pereentage cannot be accepted as being representative of the average malignant transformatioti rate of oral lieheti planus. Furthertnore. malignant transformation may have taken plaee in one or more of the patients who had been lost
328
VouTi: ei al.
Fig. I. Patient I. A) mucosal lesion of lower lip. clinically and histopathologicully diagno.scd as "compalihic with lichen planus". li) 9 months later another erosive lesion developed. No biopsy has been taken, nor any trealment has been instituted. C) 7 yr alter A was taken, a well differentiated squamous cell careinoma developed.
for follow-up. Beeau.se of tbe low migration rate of the Dutch population, such event is rather unlikely to have occurred without notification. Assuming that the prevalenee of oral liehen planus in adults found by A.xixi. (2) (1.89%) is valid for The Netherlands as well, one could expect that 13 of the 727 patients with oral squamous cell carcinoma would have had either a past or present history of lichen planus. while this aetually has been the ease in five patients (0.7%). In patient 2 of Table 3 also Cuwf/zV/w-associated lesions were observed. In fact, a biopsy of tbe lesion of the dorsum of the tongue, taken 4 yr later, was eonsistent witb the diagnosis of ehronie hyperplastic candidiasis. In retrospect, this patient may. therefore, erroneously have been included in Table 3. In retrospect, it is difficult to understand from the elinieal aspects, that in the two patients mentioned in Table 4 an initial diagnosis of oral lichen planus has been made. In one of these two patients a biopsy has been taken. In retrospect, this biopsy did show signs of at least slight epithelial dysplasia. possibly qualifying for the label of lichenoid
dysplasia. as propo.sed by KRtirciiKOKF & Eisi:NHi:R(i (4). As a result, tbe correctness of the initial bistopathologic diagnosis "compatible with oral lichen planus" is at least questionable. In the other patient of this group, it remains somewhat unexplainable why the elinical diagnosis of oral lichen planus was made initially instead of erythroplakia. Others have reported similar experiences (5). In a review of tbe literature of 220 cases of reported malignant transformation occurring in oral lichen planus. K R U K iiKoii- (•/ al. only found 15 ca.ses tbat satisfied tbeir criteria (6). In a follow-up study of 225 eases of oral liehen planus one careinoma (O.S%) developed after an observation period of 5 yr (7). In another follow-up study of 611 patients, probably including the latter group of 225 patients, nine (1.5'Mi) patients developed oral squamous eell earcinoma during follow-up, tbat ranged from 4.9 to 24 yr (8). In yet another follow-up study of oral lichen planus reported from India three carcinomas (0.4'y!.) developed in 722 patients after a mean observation period of 5.1 yr (9). In a prospeetive study in San Francisco.
consisting of 570 patients, malignant transformation occurred in 1.2% in a mean time of 3.4 yr after the onset of liehen planus (10). There is a discrepancy with regard to tbe finding of high pecentages of epithelial dysplasia in oral lichen planus. varying from 25 51"/ii and tbe extremely low malignant transformation rate ( I I . 12). In summary, our experience gives some but not convincing support to the hypothesis that oral lichen planus is a premalignant condition. From a praetieal point of view we feel somewhat reluctant to routinely inform each patient witb oral lieben planus about the possible premalignant character of their lesions. In general, we advise bi-annual dental ebeek-up, including thorough inspeetion of tbe oral mucosa.
References 1. KAI'I.AN K . HARNI.S 1,. Oral lichen planus and squatiious carcinoma. .-Irch Otolaryttgol 19X5; I I I : 543 7. 2. Ax(:i.i, T. HOLMSTRUP P. KRAMI:R
IRH.
PiNDitoRci JJ, SHI:AR M . International seminar on oral leukoplakia and assciciated lesions related lo tobacco habits.
PrenialiiiiHmt characler of oral lichen phmiis 329
Fig. 2. Patient 2. AI plaque lype lichen planus of dorsal surface of tongue. B) diagnosis of lichen planus was further supported by clinical aspect c~)f left (and right) buccal mucosa and biopsy from this site. Clinically, there seems to be overlap of lichen planus and leukoplakia. C) 5 yr after initial visit of patient a verrucous carcinoma of dorsal surface of tongue developed.
Cotnnniniiy Dent Ontl Epidemiol 19S4: 12: 145 54. 3.
Hoi.M.srRiip
P,
PiNDHORc;
.U.
Fryth-
roplakic lesions in relation to oral lichen planus. Ada Dermatovener 1979: 59: 77 84. 4. KRtiTCliKoi I DJ. liisiNiii RCi I:. I.ichcnoid dysplasia: a distinct histopathologic entity. Oral Surg Oral Med Oral Pathol 1985: 60: yi)V. 15. 5. LovAS JGL. HARSANYI BB. Ill CII:NI:II)V
AK. Oral lichenoid dysplasia: A clinicopathologic analysis. Oral Surg Oral Med Oral Pathol 1989: 68: 57 63. 6. KRIUCIIKOI I DJ, Cirn,i:R L. LASKOWSKI
S. Oral lichen planus: The evidence regarding potential malignant Iranslormal^ion. ./ Oral Pathol 1978: 7: 1 7. I'M I iNci HJ Cancer development in oral lichen planus. .-In/i Dermaiol 1973: 108: 667 9. ii .1.1. Malignant development of lichen plaiuis-alTected oral mucosa. J Oral Pathol 1988: 17: 219 25. MURTI PR. DAITARV DK. BitONSi i RB.
10 SlI VIRMAN S. GORSKY M . LoZADA-NuR F. .\ prospective follow-up study of 570 patiens with oral lichen planus: Persistancc. remission and malignant association. Oral Surg Oral Med Oral Pathol 1985: 60: 30 4. II JoNti Di: W I B . Al BRiicHT M. BAN6CZY J. WAAI. VAN DKR I. Epithelial dysplasia in oral lichen planus. .\ preliminary report o f a Dutch-Hungarian study of 100 cases. Int J Oral Surg 1984: L^: 221 5.
GUPTA PC. MKHTA F S . PiNtiiumc; JJ.
12. OiniKOYA O. GALLAGHER G . SHKLAR G .
Malignant potential of oral lichen planus: Observation in 722 patients from India. ./ Oral Paihol 1986: 15: 71 7.
A hislologic study of epithelial dysplasia in oral lichen planus. .Arch Dermatol 1985: 12L 1132-6.
P. THORN J.I. RiNnti.vi J.
