Case Report
AIII'is ' Nasus ' LarYllx (Tokyo) 18, 315-321 (1991)
MONOMORPHIC ADENOMA OF THE HARD PALATE: REPORT OF A CASE Masanori SAKAGUCHI, M.D. and Kiichiro TAGUCHI, M.D. Department 0/ Otolaryngology, Shinshu University School 0/ Medicine, Matsumoto, Japan
A rare case of monomorphic adenoma of the hard palate in a 69-yearold female is presented. Her complaints were a slowly growing mass and occasional pain of the palate. The tumor was located in the posterior region of the hard palate, and it was approximately 1.5 X 1.5 cm in size. Under general anesthesia, the tumor was excised with a wide margin of normal tissue. The palatal bone was intact. Histological diagnosis was monomorphic adenoma, basal cell type. Monomorphic adenoma is a relatively rare tumor that may originate in either major or minor salivary glands. Uniform cellularity and lack of myxoid or chondroid component are histological features which separate this tumor from pleomorphic adenoma. The upper lip is the most common site for monomorphic adenoma arising from the minor salivaly glands. However, development of monomorphic adenoma in the palate is uncommon (MINTZ, ABRAMS, and MELROSE, 1982). The purpose of this paper is to report a case of monomorphic adenoma of the hard palate, especially concerning its characteristics. CASE REPORT
A 69-year-old woman was referred to the ENT Department at Matsumoto National Hospital, Matsumoto, on May 31, 1990. She had a slowly growing palatal mass, which she had first noticed in January 1989. Her major complaint was occasional pain of the palate. Oral examination revealed a neoplastic tumor located in the posterior region of the hard palate. The tumor was approximately 1.5 x 1.5 cm in size, well circumscribed, slightly reddened, elastic hard, not movable, and not tender when palpated. The overlying mucosa appeared to be normal (Fig. 1). No lymphadenopathy of the neckw as noted. The other physical examination was within Received for pUblication
October 24, 1990 315
316
M. SAKAGUCHI and K. TAGUCHI
Fig. 1. A well circumscribed sub· mucosal tumor in left side of hard palate (indicated by arrow).
Fig. 2. A resected tumor with a margin of normal tissue.
normal limits. The chest radiograph, electrocardiogram, complete blood count, electrolytes, urinalysis, and results of liver function test were all within normal limits. An incisional biopsy was performed, and the histological diagnosis of the tumor was monomorphic adenoma. On July 25, 1990, the operation was performed under general anesthesia. The tumor was excised with a margin of uninvolved tissue, 0.5 cm in width (Fig. 2). The palatal bone underlying the tumor was intact. The patient recovered and healed without any complication. There has been no evidence of recurrence for 3 months. Histopathology. The tumor was well circumscribed by fibrous tissue and situated near intact minor salivary glands. The tumor was composed of solid cell clusters of basal cell type with nuclear palisading arrangements in the per· iphery and irregular arrangements in the center. Nonepithelial chondroid or myxoid components were lacking in this tumor (Fig. 3). Some cystic dilatation, small tubular spaces or even tubular type proliferation were observed in some tumor nests, and mucous substance with stainability for periodic acid Schiff reagent was found in some lumens (Fig. 4). In the central part of the tumor its
MONOMORPHIC ADENOMA OF HARD PALATE
317
Fig. 3. The tumor is composed of solid cell clusters of basal cell type with nuclear palisading arrangements in the periphery and irregular arrangements in the center (hematoxylin-eosin stain x 115).
Fig. 4. Partially, cystic dilatation (C) and small tubular spaces (arrows) are observed (hematoxylin-eosin stain, x 115).
stroma was seen sclerosed or hyalinized in appearance, but no necrosis was observed. These histological findings were compatible with those of basal cell type adenoma of other types of monomorphic adenomas according to the classification of World Health Organization. DISCUSSION
In 1967, KLEINSASSER and KLEIN first reported nine salivary gland tumors which they separated from pleomorphic adenoma on the basis of clinical features (all patients were over the age of 60) and characteristic histopathology (monomorphous with absence of myoepithelial cell and mesodermal mucus). Since then, a number of publications have appeared reporting similar tumors under a variety of names: monomorphic adenoma (CRUMPLER, SCHARFENBERG, and REED, 1976); basal cell adenoma (CHRIST and CROCKER, 1972; BATSAKIS, 1972); canalicular adenoma (DAVIS and DAVIS, 1971); monomorphic adenoma (canalicular type) (NELSON and JACOWAY, 1973); cystic adenoma (HARRISON, 1974);
M. SAKAGUCHI and K. TAGUCHJ
318
Table I.
Histological typing of salivary gland tumors (World Health Organization, 1972). 1.
Epithelial tumors A. Adenomas 1. Pleomorphic adenoma (mixed tumor) 2. Monomorphic adencmas a) Adenolymphoma b) Oxyphilic adenoma c) Other types B. Mucoepidermoid tumor C. Acinic cell tumor D. Carcinomas 1. Adenoid cystic carcinoma 2. Adenocarcinoma 3. Epidermoid carcinoma 4. Undifferentiated carcinoma 5. Carcinoma in pleomorphic adenoma (malignant mixed tumor) 2. Non-epithelial tumors 3. Unclassified tumors 4. Allied conditions A. Benign Iymphoepithelial lesion B. Sialosis C. Oncocytosis
dermal analogue tumor (BATSAKIS and BRANNON, 1981); and other types of monomorphic adenomas (THACKRAY and SOBIN, 1972). The World Health Organization subclassified salivary adenomas into two major subgroups, namely, pleomorphic adenoma (mixed tumor) and monomorphic adenomas. Within the monomorphic category are included adenolymphoma, oxyphilic adenoma, and other types (including canalicular, basal cell, tubular, trabecular, and clear cell types) (THACKRAY and SOBIN, 1972) (Table I). As the adenolymphoma and oxyphilic adenoma have characteristic morphologic features, they are easily recognized and are considered relatively noncontroversial. However, the other types appear to require further classification (LEVINE, KRUTCHKOFF, and EISENBERG, 1981). Recently GARDNER and DALEY (1983) presented an excellent review of the literature on the nomenclature and classification of monomorphic adenoma. In the present paper, we prefer to designate it as monomorphic adenoma, because of simplicity. Histologically, monomorphic adenoma lacks areas of mesenchyme-like tissue (that is, myxoid or chondroid areas) that are typical of pleomorphic adenoma. The tumor composes of uniform epithelial cells with dark oval or cuboidal nuclei and scant cytoplasm, which are arranged in a uniform pattern, lacking the polymorphism of the epithelium in pleomorphic adenoma. The basic arrangement of tumor cells is one of long anastomosing cords or tubles. Ductlike structures mayor may not be formed. Peripheral cells often show a palisade arrangement. In some instances, cystlike spaces, lined by palisaded basal cells,
MONOMORPHIC ADENOMA OF HARD PALATE
319
are noted. Generally the tumor stroma tends to be scanty (WALDRON, 1971; THACKRAY and LUCAS, 1974; MINTZ et al., 1982). Although the histogenesis of monomorphic ademona is uncertain, the tumor cells are presumed to be derived from ductal epithelium (WALDRON, 1971; THACKRAY and SOBIN, 1972; eHO and KIM, 1989). The incidence of monomorphic adenoma is difficult to assess because of problems in nomenclature and classification used by various reporters as mentioned above. KLEINSASSER and KLEIN (1967) reported that of their series of about 500 primary salivary gland tumors, nine cases (2 %) were monomorphic adenoma. Only one of the nine cases was minor salivary gland origin (upper lip). According to the WHO classification of salivary gland tumors, 339 major and 27 minor salivary gland tumors were histologically examined by SHARKEY (1977). Finally, monomorphic adenoma accounted for 3 % of major salivary gland tumors and 7% of minor salivary gland tumors. In 1982, MINTZ et al. reviewed the literature and reported a total of 232 cases of monomorphic adenoma, including their own twenty-one cases. The location of the tumors arising from the minor salivary glands was as follows: lip (85 cases), buccal mucosa (7 cases), palate (7 cases), floor of mouth (1 case), and not stated (2 cases). The tumors of the remaining 130 cases were found in the major salivary glands, mainly in the parotid gland. In Japan few cases of monomorphic adenoma arising from the minor salivary glands have been reported in the literature (TANAKA, ICHIKAWA, YAGI, SAITO, and SONOBE, 1986; MURAKAMI and NAKAE, 1989), though KANEKO (1978) found 33 cases of monomorphic adenoma in 450 parotid gland tumors. Thus such tumor of the hard palate as reported in the present paper is uncommon. The commonest symptom of monomorphic adenoma arising from the palate is a lump, which is the only symptom in most cases. Other symptoms are pain, bleeding, and denture difficulties. Ulceration of the overlying mucosa is unusual (ENEROTH, HJERTMAN, and MOBERGER, 1972; MINTZ et al., 1982). The best treatment for monomorphic adenoma of the minor salivary glands is to excise with a limited border of normal tissue (MINTZ et al., 1982). Since this tumor is a benign lesion, recurrence after local excision rarely occurs (WALDRON, 1971; ENEROTH et al., 1972). As compared with pleomorphic adenoma, monomorphic adenoma seldom gives rise to malignancies (CHEN, 1985). There are only a few cases of carcinomas arising from monomorphic adenoma of minor or major salivary glands in the literature (CHEN, 1985; LUNA, BATSAKIS, TORTOLEDO, and DEL JUNCO, 1989). CONCLUSION
A case of monomorphic adenoma of the hard palate was reported. The terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma are relatively recent ones in the study of the pathology of salivary gland tumors and,
320
M. SAKAGUCHI and K. TAGUCHI
regrettably, there has been considerable confusion in their use. As more of these tumors are studied by electron microscopy, histochemistry, and other techniques, a more rational basis for their classification may emerge and clear-cut subtypes may be formulated. And perhaps with increased recognition and further documentation in the literature, a more accurate measure of the epidemiology of this uncommon neoplasm may be achieved. The authors would like to thank Prof. Hidekazu Shigematsu, Department of Pathology, Shinshu University School of Medicine, for permission to publish the report and for his help in reviewing and preparation of the histological slides.
REFERENCES BATSAKIS, J. G.: Basal cell adenoma of the parotid gland. Cancer 29: 226-230, 1972. BATSAKIS, J. G., and BRANNON, R. B.: Dermal analogue tumours of major salivary glands. J. Laryngol. 0101. 95: 155-164, 1981. CHEN, K. T. K.: Carcinoml arising in m:ll1omorphic adenoma of the salivary gland. Alii. J. Ololaryngol. 6: 39-41, 1985. CHO, K. J., and KIM, Y.: Monomorphic adenomas of the salivary glands. A clinico-pathologic study of 12 cases with immunohistochemical observation. Palhol. Res. Pracl. 184: 614620,1989. CHRIST, T. F., and CROCKER, D.: Basal cell adenoma of minor salivary gland origin. Cancer 30: 214-219, 1972. CRUMPLER, c., SCHARFENBERG, J. c., and REED, R. J.: Monomorphic adenomas of salivary glands. Trabecular-tubular, canalicular, and basaloid variants. Cancer 38: 193-200, 1976. DAVIS, W., and DAVIS, W., Jr.: Canalicular adenoma. Report of case. J. Oral SlIrg. 29: 500-501, 1971. ENEROTH, C. M., HJERTMAN, L., and MOBERGER, G.: Salivary gland adenomas of the palate. Acla Ololaryngol. 73: 305-315, 1972. GARDNER, D. G., and DALEY, T. D.: The use of the terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma as applied to salivary gland tumors. Oral SlIrg. Oral Med. Oral PalllO/. 56: 608-615, 1983. HARRISON, J. D.: Cystic adenoma of a minor salivary gland. A histochemical study. J. Palhol. 114: 29-38, 1974. KANEKO, T.: Parotid swelling and clinical aspects. Olologia (FlIkuoka) 24: 885-890, 1978. KLEINSASSER, 0., and KLEIN, H. J.: Basalzelladenome del' Speicheldriisen. Arch. Klin. Exp. Ohr. Nas. Kehlkopfheilkd. 189: 302-316, 1967. LEVINE, J., KRUTCHKOFF, D. J., and EISENBERG, E.: Monomorphic adenoma of minor salivary glands. A reappraisal and report of nine new cases. J. Oral SlIrg. 39: 101-107, 1981. LUNA, M. A., BATSAKIS, J. G., TORTOLEDO, M. E., and DEL JUNCO, G. W.: Carcinomas ex monomorphic adenoma of salivary glands. J. Laryngol. DIal. 103: 756-759, 1989. MINTZ, G. A., ABRAMS, A. M., and MELROSE, R. J.: Monomorphic adenomas of the major and minor salivary glands. Oral Surg. Oral Med. Oral Palhol. 53: 375-386, 1982. MURAKAMI, M., and NAKAE, S.: A case of monomorphic tubular adenoma (canalicular type) of minor salivary gland. Ololaryngol. Head Neck SlIrg. (Tokyo) 61: 1101-1105, 1989. NELSON, J. F., and JACOWAY, J. R.: Monomorphic adenoma (canalicular type). Report of 29 cases. Cancer 31: 1511-1513, 1973.
MONOMORPHIC ADENOMA OF HARD PALATE
321
SHARKEY, F. E.: Systematic evaluation of the World Health Organization classification of salivary gland tumors. A clinicopathologic study of 366 cases. Am. J. Clill. Pathol. 67: 272- 278, 1977. TANAKA, S., ICHIKAWA, R., YAGI, N., SAITO, H., and SONOBE, H.: Monomorphic adenoma (trabecular type) of the soft palate. Fract. Otol. (Kyoto) 79: 1101-1105, 1986. THACKRAY, A. c., and LUCAS, R. B.: Atlas of Tumor Pathology, Fascicle 10, Tumors of the Major Salivary Glands, Armed Forces Institute of Pathology, Washington, D.C., 1974. THACKRAY, A. c., and SOBIN, L. H.: Histological Typing of Salivary Gland Tumours, World Health Organization, Geneva, 1972. WALDRON, C. A.: Comment (in Davis, W., and Davis, W., Jr.: Canalicular adenoma. Report of case). J. Oral Surg. 29: 502, 1971.
Request reprints to:
Dr. M. Sakaguchi, Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390, Japan
AIII'is ' Nasus ' LarYllx (Tokyo) 18, 315-321 (1991)
MONOMORPHIC ADENOMA OF THE HARD PALATE: REPORT OF A CASE Masanori SAKAGUCHI, M.D. and Kiichiro TAGUCHI, M.D. Department 0/ Otolaryngology, Shinshu University School 0/ Medicine, Matsumoto, Japan
A rare case of monomorphic adenoma of the hard palate in a 69-yearold female is presented. Her complaints were a slowly growing mass and occasional pain of the palate. The tumor was located in the posterior region of the hard palate, and it was approximately 1.5 X 1.5 cm in size. Under general anesthesia, the tumor was excised with a wide margin of normal tissue. The palatal bone was intact. Histological diagnosis was monomorphic adenoma, basal cell type. Monomorphic adenoma is a relatively rare tumor that may originate in either major or minor salivary glands. Uniform cellularity and lack of myxoid or chondroid component are histological features which separate this tumor from pleomorphic adenoma. The upper lip is the most common site for monomorphic adenoma arising from the minor salivaly glands. However, development of monomorphic adenoma in the palate is uncommon (MINTZ, ABRAMS, and MELROSE, 1982). The purpose of this paper is to report a case of monomorphic adenoma of the hard palate, especially concerning its characteristics. CASE REPORT
A 69-year-old woman was referred to the ENT Department at Matsumoto National Hospital, Matsumoto, on May 31, 1990. She had a slowly growing palatal mass, which she had first noticed in January 1989. Her major complaint was occasional pain of the palate. Oral examination revealed a neoplastic tumor located in the posterior region of the hard palate. The tumor was approximately 1.5 x 1.5 cm in size, well circumscribed, slightly reddened, elastic hard, not movable, and not tender when palpated. The overlying mucosa appeared to be normal (Fig. 1). No lymphadenopathy of the neckw as noted. The other physical examination was within Received for pUblication
October 24, 1990 315
316
M. SAKAGUCHI and K. TAGUCHI
Fig. 1. A well circumscribed sub· mucosal tumor in left side of hard palate (indicated by arrow).
Fig. 2. A resected tumor with a margin of normal tissue.
normal limits. The chest radiograph, electrocardiogram, complete blood count, electrolytes, urinalysis, and results of liver function test were all within normal limits. An incisional biopsy was performed, and the histological diagnosis of the tumor was monomorphic adenoma. On July 25, 1990, the operation was performed under general anesthesia. The tumor was excised with a margin of uninvolved tissue, 0.5 cm in width (Fig. 2). The palatal bone underlying the tumor was intact. The patient recovered and healed without any complication. There has been no evidence of recurrence for 3 months. Histopathology. The tumor was well circumscribed by fibrous tissue and situated near intact minor salivary glands. The tumor was composed of solid cell clusters of basal cell type with nuclear palisading arrangements in the per· iphery and irregular arrangements in the center. Nonepithelial chondroid or myxoid components were lacking in this tumor (Fig. 3). Some cystic dilatation, small tubular spaces or even tubular type proliferation were observed in some tumor nests, and mucous substance with stainability for periodic acid Schiff reagent was found in some lumens (Fig. 4). In the central part of the tumor its
MONOMORPHIC ADENOMA OF HARD PALATE
317
Fig. 3. The tumor is composed of solid cell clusters of basal cell type with nuclear palisading arrangements in the periphery and irregular arrangements in the center (hematoxylin-eosin stain x 115).
Fig. 4. Partially, cystic dilatation (C) and small tubular spaces (arrows) are observed (hematoxylin-eosin stain, x 115).
stroma was seen sclerosed or hyalinized in appearance, but no necrosis was observed. These histological findings were compatible with those of basal cell type adenoma of other types of monomorphic adenomas according to the classification of World Health Organization. DISCUSSION
In 1967, KLEINSASSER and KLEIN first reported nine salivary gland tumors which they separated from pleomorphic adenoma on the basis of clinical features (all patients were over the age of 60) and characteristic histopathology (monomorphous with absence of myoepithelial cell and mesodermal mucus). Since then, a number of publications have appeared reporting similar tumors under a variety of names: monomorphic adenoma (CRUMPLER, SCHARFENBERG, and REED, 1976); basal cell adenoma (CHRIST and CROCKER, 1972; BATSAKIS, 1972); canalicular adenoma (DAVIS and DAVIS, 1971); monomorphic adenoma (canalicular type) (NELSON and JACOWAY, 1973); cystic adenoma (HARRISON, 1974);
M. SAKAGUCHI and K. TAGUCHJ
318
Table I.
Histological typing of salivary gland tumors (World Health Organization, 1972). 1.
Epithelial tumors A. Adenomas 1. Pleomorphic adenoma (mixed tumor) 2. Monomorphic adencmas a) Adenolymphoma b) Oxyphilic adenoma c) Other types B. Mucoepidermoid tumor C. Acinic cell tumor D. Carcinomas 1. Adenoid cystic carcinoma 2. Adenocarcinoma 3. Epidermoid carcinoma 4. Undifferentiated carcinoma 5. Carcinoma in pleomorphic adenoma (malignant mixed tumor) 2. Non-epithelial tumors 3. Unclassified tumors 4. Allied conditions A. Benign Iymphoepithelial lesion B. Sialosis C. Oncocytosis
dermal analogue tumor (BATSAKIS and BRANNON, 1981); and other types of monomorphic adenomas (THACKRAY and SOBIN, 1972). The World Health Organization subclassified salivary adenomas into two major subgroups, namely, pleomorphic adenoma (mixed tumor) and monomorphic adenomas. Within the monomorphic category are included adenolymphoma, oxyphilic adenoma, and other types (including canalicular, basal cell, tubular, trabecular, and clear cell types) (THACKRAY and SOBIN, 1972) (Table I). As the adenolymphoma and oxyphilic adenoma have characteristic morphologic features, they are easily recognized and are considered relatively noncontroversial. However, the other types appear to require further classification (LEVINE, KRUTCHKOFF, and EISENBERG, 1981). Recently GARDNER and DALEY (1983) presented an excellent review of the literature on the nomenclature and classification of monomorphic adenoma. In the present paper, we prefer to designate it as monomorphic adenoma, because of simplicity. Histologically, monomorphic adenoma lacks areas of mesenchyme-like tissue (that is, myxoid or chondroid areas) that are typical of pleomorphic adenoma. The tumor composes of uniform epithelial cells with dark oval or cuboidal nuclei and scant cytoplasm, which are arranged in a uniform pattern, lacking the polymorphism of the epithelium in pleomorphic adenoma. The basic arrangement of tumor cells is one of long anastomosing cords or tubles. Ductlike structures mayor may not be formed. Peripheral cells often show a palisade arrangement. In some instances, cystlike spaces, lined by palisaded basal cells,
MONOMORPHIC ADENOMA OF HARD PALATE
319
are noted. Generally the tumor stroma tends to be scanty (WALDRON, 1971; THACKRAY and LUCAS, 1974; MINTZ et al., 1982). Although the histogenesis of monomorphic ademona is uncertain, the tumor cells are presumed to be derived from ductal epithelium (WALDRON, 1971; THACKRAY and SOBIN, 1972; eHO and KIM, 1989). The incidence of monomorphic adenoma is difficult to assess because of problems in nomenclature and classification used by various reporters as mentioned above. KLEINSASSER and KLEIN (1967) reported that of their series of about 500 primary salivary gland tumors, nine cases (2 %) were monomorphic adenoma. Only one of the nine cases was minor salivary gland origin (upper lip). According to the WHO classification of salivary gland tumors, 339 major and 27 minor salivary gland tumors were histologically examined by SHARKEY (1977). Finally, monomorphic adenoma accounted for 3 % of major salivary gland tumors and 7% of minor salivary gland tumors. In 1982, MINTZ et al. reviewed the literature and reported a total of 232 cases of monomorphic adenoma, including their own twenty-one cases. The location of the tumors arising from the minor salivary glands was as follows: lip (85 cases), buccal mucosa (7 cases), palate (7 cases), floor of mouth (1 case), and not stated (2 cases). The tumors of the remaining 130 cases were found in the major salivary glands, mainly in the parotid gland. In Japan few cases of monomorphic adenoma arising from the minor salivary glands have been reported in the literature (TANAKA, ICHIKAWA, YAGI, SAITO, and SONOBE, 1986; MURAKAMI and NAKAE, 1989), though KANEKO (1978) found 33 cases of monomorphic adenoma in 450 parotid gland tumors. Thus such tumor of the hard palate as reported in the present paper is uncommon. The commonest symptom of monomorphic adenoma arising from the palate is a lump, which is the only symptom in most cases. Other symptoms are pain, bleeding, and denture difficulties. Ulceration of the overlying mucosa is unusual (ENEROTH, HJERTMAN, and MOBERGER, 1972; MINTZ et al., 1982). The best treatment for monomorphic adenoma of the minor salivary glands is to excise with a limited border of normal tissue (MINTZ et al., 1982). Since this tumor is a benign lesion, recurrence after local excision rarely occurs (WALDRON, 1971; ENEROTH et al., 1972). As compared with pleomorphic adenoma, monomorphic adenoma seldom gives rise to malignancies (CHEN, 1985). There are only a few cases of carcinomas arising from monomorphic adenoma of minor or major salivary glands in the literature (CHEN, 1985; LUNA, BATSAKIS, TORTOLEDO, and DEL JUNCO, 1989). CONCLUSION
A case of monomorphic adenoma of the hard palate was reported. The terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma are relatively recent ones in the study of the pathology of salivary gland tumors and,
320
M. SAKAGUCHI and K. TAGUCHI
regrettably, there has been considerable confusion in their use. As more of these tumors are studied by electron microscopy, histochemistry, and other techniques, a more rational basis for their classification may emerge and clear-cut subtypes may be formulated. And perhaps with increased recognition and further documentation in the literature, a more accurate measure of the epidemiology of this uncommon neoplasm may be achieved. The authors would like to thank Prof. Hidekazu Shigematsu, Department of Pathology, Shinshu University School of Medicine, for permission to publish the report and for his help in reviewing and preparation of the histological slides.
REFERENCES BATSAKIS, J. G.: Basal cell adenoma of the parotid gland. Cancer 29: 226-230, 1972. BATSAKIS, J. G., and BRANNON, R. B.: Dermal analogue tumours of major salivary glands. J. Laryngol. 0101. 95: 155-164, 1981. CHEN, K. T. K.: Carcinoml arising in m:ll1omorphic adenoma of the salivary gland. Alii. J. Ololaryngol. 6: 39-41, 1985. CHO, K. J., and KIM, Y.: Monomorphic adenomas of the salivary glands. A clinico-pathologic study of 12 cases with immunohistochemical observation. Palhol. Res. Pracl. 184: 614620,1989. CHRIST, T. F., and CROCKER, D.: Basal cell adenoma of minor salivary gland origin. Cancer 30: 214-219, 1972. CRUMPLER, c., SCHARFENBERG, J. c., and REED, R. J.: Monomorphic adenomas of salivary glands. Trabecular-tubular, canalicular, and basaloid variants. Cancer 38: 193-200, 1976. DAVIS, W., and DAVIS, W., Jr.: Canalicular adenoma. Report of case. J. Oral SlIrg. 29: 500-501, 1971. ENEROTH, C. M., HJERTMAN, L., and MOBERGER, G.: Salivary gland adenomas of the palate. Acla Ololaryngol. 73: 305-315, 1972. GARDNER, D. G., and DALEY, T. D.: The use of the terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma as applied to salivary gland tumors. Oral SlIrg. Oral Med. Oral PalllO/. 56: 608-615, 1983. HARRISON, J. D.: Cystic adenoma of a minor salivary gland. A histochemical study. J. Palhol. 114: 29-38, 1974. KANEKO, T.: Parotid swelling and clinical aspects. Olologia (FlIkuoka) 24: 885-890, 1978. KLEINSASSER, 0., and KLEIN, H. J.: Basalzelladenome del' Speicheldriisen. Arch. Klin. Exp. Ohr. Nas. Kehlkopfheilkd. 189: 302-316, 1967. LEVINE, J., KRUTCHKOFF, D. J., and EISENBERG, E.: Monomorphic adenoma of minor salivary glands. A reappraisal and report of nine new cases. J. Oral SlIrg. 39: 101-107, 1981. LUNA, M. A., BATSAKIS, J. G., TORTOLEDO, M. E., and DEL JUNCO, G. W.: Carcinomas ex monomorphic adenoma of salivary glands. J. Laryngol. DIal. 103: 756-759, 1989. MINTZ, G. A., ABRAMS, A. M., and MELROSE, R. J.: Monomorphic adenomas of the major and minor salivary glands. Oral Surg. Oral Med. Oral Palhol. 53: 375-386, 1982. MURAKAMI, M., and NAKAE, S.: A case of monomorphic tubular adenoma (canalicular type) of minor salivary gland. Ololaryngol. Head Neck SlIrg. (Tokyo) 61: 1101-1105, 1989. NELSON, J. F., and JACOWAY, J. R.: Monomorphic adenoma (canalicular type). Report of 29 cases. Cancer 31: 1511-1513, 1973.
MONOMORPHIC ADENOMA OF HARD PALATE
321
SHARKEY, F. E.: Systematic evaluation of the World Health Organization classification of salivary gland tumors. A clinicopathologic study of 366 cases. Am. J. Clill. Pathol. 67: 272- 278, 1977. TANAKA, S., ICHIKAWA, R., YAGI, N., SAITO, H., and SONOBE, H.: Monomorphic adenoma (trabecular type) of the soft palate. Fract. Otol. (Kyoto) 79: 1101-1105, 1986. THACKRAY, A. c., and LUCAS, R. B.: Atlas of Tumor Pathology, Fascicle 10, Tumors of the Major Salivary Glands, Armed Forces Institute of Pathology, Washington, D.C., 1974. THACKRAY, A. c., and SOBIN, L. H.: Histological Typing of Salivary Gland Tumours, World Health Organization, Geneva, 1972. WALDRON, C. A.: Comment (in Davis, W., and Davis, W., Jr.: Canalicular adenoma. Report of case). J. Oral Surg. 29: 502, 1971.
Request reprints to:
Dr. M. Sakaguchi, Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390, Japan
