Comparative clinicopathological study of intraoral sebaceous hyperplasia and sebaceous adenoma

Comparative clinicopathological study of intraoral sebaceous hyperplasia and sebaceous adenoma Rebeca Souza Azevedo, DDS, MSc,a Oslei Paes Almeida, DDS, PhD,a Juliana Noronha Santos Netto, DDS,b Águida Maria Menezes Aguiar Miranda, DDS,b Teresa Cristina Ribeiro Bartholomeu Santos, DDS, PhD,b Ricardo Della Coletta, DDS, PhD,a Márcio Ajudarte Lopes, DDS, PhD,a and Fábio Ramôa Pires, DDS, PhD,b Piracicaba/SP and Rio de Janeiro/RJ, Brazil STATE UNIVERSITY OF CAMPINAS AND ESTÁCIO DE SÁ UNIVERSITY

Objective. The objective of this study was to compare the clinicopathological features of oral sebaceous hyperplasia and sebaceous adenoma. Study design. Clinical data, microscopical characteristics, and ki-67 immunoexpression were comparatively analyzed on 2 intraoral sebaceous adenomas, 6 intraoral sebaceous hyperplasias, and 21 normal intraoral sebaceous glands. Results. Clinically, sebaceous glands presented as multiple separated papules, sebaceous hyperplasias as a single enlarged papule, and sebaceous adenoma as a well-defined nodule. Microscopically, sebaceous adenoma presented an increased number of lobules, smaller lobules, and a greater number of germinative/squamous cells. Sebaceous hyperplasia also had an increased number of lobules and fewer number of germinative/squamous cells, as compared to normal oral sebaceous glands. Ki-67 expression was seen only in germinative cells and counts were higher in sebaceous adenomas followed by hyperplasias and normal glands. Conclusions. Sebaceous hyperplasias and adenomas showed different clinical, microscopic, and proliferative characteristics, suggesting the usefulness of the studied criteria on diagnosis of these uncommon oral lesions. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107:100-104)

Although sebaceous glands (SG) have been classically considered as cutaneous appendages, they can be found in many other surfaces such as oral, genital, laryngeal, and esophageal mucosas, where they are named free sebaceous glands.1-3 Intraoral sebaceous glands (IOSG), also known as Fordyce’s granules, are encountered in up to 80% of adults, particularly in the upper lip and buccal mucosa.2,4 They are histologically identical to cutaneous SG, except for the lack of association with hair follicles and apparent decreased or absent secretory function.5 Intraoral sebaceous adenomas (IOSA) are uncommon tumors in the oral cavity, with only 9 well-documented cases reported in the English-language literature since 1968.6-13 Similarly, intraoral sebaceous hyperplasia (IOSH), defined as an abnormal enlargeThis research was supported by CAPES, FAPESP, FAPERJ, and CNPq, Brazil. a Oral Pathology and Oral Diagnosis, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas (UNICAMP), Piracicaba/SP, Brazil. b Stomatology and Oral Pathology, School of Dentistry, Estácio de Sá University, Rio de Janeiro/RJ, Brazil. Received for publication Jun 23, 2008; returned for revision Sep 10, 2008; accepted for publication Sep 24, 2008. 1079-2104/$ - see front matter © 2009 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2008.09.027

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ment of an IOSG, it is also uncommonly diagnosed in the oral cavity, with only 22 cases reported in the English-language literature since its diagnostic criteria were defined in 1992.13-17 Since there are no comparative clinicopathological studies between IOSA and IOSH, the aim of this study was to describe the clinical, histopathological, morphometrical, and proliferative characteristics of IOSA and IOSH, comparing their features with normal IOSG. MATERIAL AND METHODS The files of the Oral Pathology Laboratory, Piracicaba Dental School, State University of Campinas, and from the Oral Pathology Laboratory, Estácio de Sá University, Brazil, were reviewed and all cases diagnosed as oral sebaceous lesions (IOSG, IOSH, and IOSA) were selected. These cases were histologically reviewed by 4 of the authors (R.S.A., T.C.R.B.S., O.P.A., and F.R.P.) to confirm initial diagnosis and after this review, 21 cases of IOSG, 6 cases of IOSH, and 2 cases of IOSA were selected for further evaluation (Table I). Case 2 of IOSA and cases 5 and 6 of IOSH were previously reported by Kaminagakura et al. (2003).13 Clinical data from all cases were retrieved from the laboratory records. This study was carried out with approval of the Research Ethics Committee, Piracicaba Dental School, State University of Campinas.

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Table I. Clinical data from 2 cases of intraoral sebaceous adenomas and 6 cases of intraoral sebaceous hyperplasia used on this study

Histomorphometrical analysis was performed under light microscopy, with the aid of an image computer analyzer (KS400 software; Kontrol KE 2.00, Zeiss, Jena, Germany), in 5-␮m hematoxylin and eosin (HE)stained sections. The parameters analyzed included number of lobules and excretory ducts per case (⫻25 magnification), perimeter of the lobules (⫻100 magnification), and number of sebocytes and germinative/ squamous cells per lobule (⫻400 magnification). All measures were analyzed in 10 different microscopic fields and, from these data, the mean value was calculated for each sample. Perimeter was obtained by measuring manually the total contour of the lobule using the computer analyzer adjustable line. For immunohistochemical reactions, 3-␮m sections mounted on silanized glass histological slides were used. The specimens were first deparaffinized, hydrated, and incubated with 10% hydrogen peroxide for 30 minutes, to inhibit endogenous peroxidase. Antigen retrieval was performed in a microwave oven using 10 mM citrate buffer and overnight incubation with the primary monoclonal antibody anti-Ki-67 (Clone MIB-1, Dako, Glostrup, Denmark, dilution 1:200). Secondary antibodies were conjugated to a streptavidinbiotin-peroxidase system (StreptABComplex/HRP Duet, Mouse/Rabbit, Dako A/S, Denmark, dilution 1:500), and diaminobenzidine was used as the chromogen. Slides were counterstained with Mayer’s hematoxylin, mounted, and analyzed. KS400 software was used to count the percentage of positive cells considering 500 cells per slide.

less swelling on the area lasting 1 year, and case 2 presented as a gray-yellowish nodular lesion on the left retromolar pad of a 71-year-old female.13 Six cases of IOSH were obtained by excisional biopsies from asymptomatic yellowish single plaques, mainly located on buccal mucosa and retromolar pad of females.13 Clinical data from the 8 cases used in this study are summarized in Table I. IOSG were clinically characterized as multiple yellowish papules especially located on buccal mucosa removed because of their abnormal appearance or patient request (Fig. 1). Microscopically, normal IOSG were characterized by lobules composed of 1 layer of peripheral undifferentiated flattened germinative cells and central differentiated sebocytes, showing various grades of maturation. The sebaceous alveolar unit discharged through a short duct lined by stratified squamous epithelium on the mucosal surface in 13 of 21 cases studied. In general, IOSH attempted to reproduce the normal IOSG, presenting an evident larger number of organized lobules converging to a single excretory duct that was dilated in 2 of 8 cases. In contrast, both cases of IOSA showed a sharply demarcated, but not encapsulated, mass of lobules, containing varied proportion of sebocytes and germinative/squamous cells, without an excretory duct connected to the surface epithelium. Some lobules were associated with ductlike structures and presented cystic degeneration. There was neither atypia nor mitosis, but a moderate chronic inflammatory infiltrate could be identified (Fig. 2). Histomorphometrical findings are shown in Tables II and III. In summary, the mean number of lobules in IOSH (25 lobules) was higher than in normal IOSG (5.2 lobules), but the mean perimeter of the lobules was similar in both groups (IOSG – 824.2 ␮m versus IOSH – 922.5 ␮m). IOSA presented a very large mean number of lobules (289 lobules), but the mean perimeter of each lobule was significantly smaller (436.3 ␮m). The ratio of sebocytes to germinative/squamous cells was slightly higher in IOSG (1.6:1.0) than in IOSH (1.3: 1.0), with the lowest values found in IOSA (0.6:1.0), resulting consequently both in a smaller number of sebocytes and an increased number of germinative/ squamous cells in the latter (Fig. 3). Ki-67 positivity was observed only in germinative/squamous cells, with IOSA showing the highest values (21%), followed by IOSH (16.9%) and IOSG (10%) (Fig. 4).

RESULTS IOSA were obtained by excisional biopsies from asymptomatic nodular exophytic lesions, clinically resembling fibrous hyperplasias. Case 1 was a 1.0-cm yellowish soft mobile exophytic nodule on the buccal mucosa of a 65-year-old male, complaining of a pain-

DISCUSSION Normal IOSG present clinically as multiple small papules, usually with a diameter of 1 to 3 mm, whereas IOSH are asymptomatic isolated whitish to yellowish plaques larger than 5 mm.17,18 Fordyce’s granules are more numerous on the lips and buccal mucosa, whereas

Case 1 2 3 4 5 6 7 8

Diagnosis Sebaceous Sebaceous Sebaceous Sebaceous Sebaceous Sebaceous Sebaceous Sebaceous

adenoma adenoma hyperplasia hyperplasia hyperplasia hyperplasia hyperplasia hyperplasia

Gender

Age, y

Site

F M F F M F NA F

71 65 33 42 48 35 NA 23

Retromolar pad Buccal mucosa Retromolar pad Retromolar pad Buccal mucosa Buccal mucosa Buccal mucosa Alveolar mucosa

NA, not available.

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Fig. 1. Clinical aspects of intraoral sebaceous lesions. A, Fordyce’s granules on the right buccal mucosa. B, Sebaceous hyperplasia showing a yellowish papule on the right retromolar pad (case 3). C, Sebaceous adenoma showing as a yellowish nodule on the left buccal mucosa. Note the presence of normal sebaceous glands adjacent to the nodule (case 1).

Fig. 2. Histological features of intraoral sebaceous lesions (hematoxylin and eosin [HE], original magnification ⫻25). A, Normal intraoral sebaceous glands. B, Intraoral sebaceous hyperplasia showing an increased number of organized lobules, relative to normal glands. C, Intraoral sebaceous adenoma showing an increased number of disorganized lobules, some of them presenting central cystic degeneration. Note the presence of normal sebaceous glands on the right upper portion of the figure. This image was created from 6 photographs taken at ⫻25 original magnification.

Table II. Mean number and perimeter of lobules in intraoral sebaceous adenomas, intraoral sebaceous hyperplasias, and normal intraoral sebaceous glands Lobules Diagnosis

No.

Perimeter, ␮m

Intraoral sebaceous adenoma (n ⫽ 2) Intraoral sebaceous hyperplasia (n ⫽ 6) Intraoral sebaceous glands (n ⫽ 21)

289

436.3

25 (⫾13.4)

922.5 (⫾203.1)

5.2 (⫾2.1)

824.3 (⫾165.2)

IOSH were more common on the buccal mucosa and retromolar pad of adults.14-16 Morphologically IOSH mimics normal sebaceous glands, but the clinical and microscopical aspects suggest it is in fact a hyperplasia. IOSA is an asymptomatic yellowish soft well-circumscribed nodule, clinically similar to fibrous hyperplasia and other benign lesions, such as lipoma.6,8,12 Our study reinforces the clinical and microscopical characteristics of IOSH and IOSA, and adds the 10th case of IOSA reported on the English-language literature. It is also interesting to report that our patients with IOSA were 65 and 71 years old. On the other hand those with IOSH had a mean age of 36 years, much younger than the mean age of 60 years reported in the literature.14-17

Table III. Mean number of sebocytes and squamous cells in intraoral sebaceous adenomas, intraoral sebaceous hyperplasias, and normal intraoral sebaceous glands Cellular types Diagnosis

Sebocytes

Germinative/ squamous cells

Ratio

Intraoral sebaceous adenoma (n ⫽ 2) Intraoral sebaceous hyperplasia (n ⫽ 6) Intraoral sebaceous glands (n ⫽ 21)

54.5

86.9

0.6 : 1.0

44.7 (⫾6.1)

1.3 : 1.0

45.7 (⫾12.6)

1.6 : 1.0

56.9 (⫾7.2) 74 (⫾15.2)

SG are composed of lobules containing a peripheral single or double layer of germinative flattened squamous cells, which proliferate and differentiate to the typical mature, clear sebaceous cells.1,19,20 The nucleus wrinkles and disappears, and the sebocytes burst to form the sebum that is discharged into a short single duct connected with the surface.5,18 IOSH is microscopically composed of a larger number of well-organized lobules that attempt to reproduce the normal IOSG, converging into a single excretory duct that can be dilated.3,13,14,16,17 The diagnostic criteria of IOSH proposed by Daley in 199214 included a number of

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Fig. 3. Histomorphometrical features of intraoral sebaceous lesions (HE, original magnification ⫻200). A, Normal intraoral sebaceous gland. B, Intraoral sebaceous hyperplasia maintaining the lobule’s perimeter and the proportion of sebocyte and germinative/squamous cells similar to the normal sebaceous gland. C, Intraoral sebaceous adenoma showing a smaller lobule, some foci of chronic inflammatory infiltrate, and an increased number of germinative/squamous cells.

Fig. 4. Ki-67 positivity restricted to germinative cells (Immunoperoxidase, original magnification ⫻400). A, Normal intraoral sebaceous gland. B, Intraoral sebaceous hyperplasia. C, Intraoral sebaceous adenoma.

lobules no lower than 15, and the mean number that he found was 30, similar to our data. Our results also showed that the mean number of lobules in IOSH was significantly different when compared with normal IOSG and IOSA, supporting that this parameter is significant for differential diagnosis. IOSA is usually a sharply demarcated lobular tumor, but this does not seem to be a useful characteristic in the differential diagnosis. Different from normal IOSG and IOSH, IOSA present a variable proportion of sebocytes and germinative/squamous cells. Some lobules present only a single layer of germinative cells, whereas in others the germinative/squamous cells can predominate.3,11,12 IOSA also attempt to reproduce normal SG, but the general morphology is different and the morphological and quantitative patterns were clearly distinct, including a higher proliferative rate, as shown by ki-67 labeling. The higher mean number of lobules, the presence of cystic spaces, and the lower mean perimeter of the lobules also suggest a higher proliferative potential in IOSA, possibly leading to impairment of normal sebocyte maturation. The mean Ki-67 labeling indices were higher in IOSA, followed by IOSH and IOSG. Ki-67 expression observed in IOSA was similar to the data previously reported in cutaneous sebaceous adenoma, especially when differentiating them from sebaceous carcinoma.21,22 As expected, the Ki-67 indices are a parameter for the amount of germinative cells, probably corresponding to the proliferative compartment of normal glands, hyperplasias,

and adenomas.21 The lower proliferative indices observed in our normal IOSG probably reflect their apparent decreased or absent secretory function.4 All sebocytes were negative, confirming their role in producing and accumulating lipids as secretory cells, without proliferative activity. In summary, we presented a comparative clinical, microscopical and immunohistochemical study of IOSH and IOSA, and also the 10th case of IOSA reported in the English-language literature. According to our results, these lesions showed distinct clinical, morphological and proliferative characteristics, suggesting the usefulness of some microscopic diagnostic criteria. IOSH seems to present intermediate clinicopathological features between IOSG and IOSA. As these entities are uncommon, other similar studies are desired in order to better establish their microscopical and biological characteristics. We thank Ana Cristina do Amaral Godoy for the immunohistochemical assistance. REFERENCES 1. Ham AW, Cormack DH. Histology. 8th ed. Philadelphia: J.B. Lippincott; 1979. 2. Batsakis JG, el-Naggar AK. Sebaceous lesions of salivary glands and oral cavity. Ann Otol Rhinol Laryngol 1990;99:416-8. 3. Daley T. Pathology of intraoral sebaceous glands. J Oral Pathol Med 1993;22:241-5. 4. Whitaker SB, Vigneswaran N, Singh BB. Androgen receptor status of the oral sebaceous glands. Am J Dermatopathol 1997;19:415-8.

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5. Monteil RA. Fordyce’s spots: disease, heterotopia or adenoma? Histological and ultrastructural study. J Biol Buccale 1981;9:109-28. 6. Miller AS, McCrea MW. Sebaceous gland adenoma of the buccal mucosa: report of a case. J Oral Surg 1968;26:593-5. 7. Epker BN, Henny FA. Intra-oral sebaceous gland adenoma. Cancer 1971;27:987-1000. 8. Lipani C, Woytash JJ, Greene GW Jr. Sebaceous adenoma of the oral cavity. J Oral Maxillofac Surg 1983;41:56-60. 9. Orlian AI, Salman L, Reddi T, Yamane GM, Chaudhry AP. Sebaceous adenoma of the oral mucosa. J Oral Med 1987;42:38-9. 10. Ferguson JW, Geary CP, MacAlister AD. Sebaceous cell adenoma. Rare intra-oral occurerrence of a tumor which is a frequent marker of Torre’s syndrome. Pathology 1987;19:204-8. 11. Iezzi G, Rubini C, Fioroni M, Piattelli A. Sebaceous adenoma of the cheek. Oral Oncol 2002;38:111-3. 12. Izutsu T, Kumamoto H, Kimizuka S, Ooya K. Sebaceous adenoma in the retromolar region: report of a case with a review of the English literature. Int J Oral Maxillofac Surg 2003;32:423-6. 13. Kaminagakura E, Andrade CR, Rangel AL, Colleta RD, Graner E, Almeida OP, et al. Sebaceous adenoma of oral cavity: report of case and comparative proliferation study with sebaceous gland hyperplasia and Fordyce’s granules. Oral Dis 2003;9:323-7. 14. Daley T. Intraoral sebaceous hyperplasia. Diagnostic criteria. Oral Surg Oral Med Oral Pathol 1992;74:343-7. 15. Koutlas IG, Yaholnitsky B. Oral sebaceous retention phenomenon. J Periodontol 1994;65:186-8. 16. Dent CD, Hunter WE, Svirsky JA. Sebaceous gland hyperplasia and literature review. J Oral Maxillofac Surg 1995;53:936-8. 17. Takeda Y, Satoh M, Nakamura S, Takamaru H. Sebaceous

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Reprint requests: Fábio Ramôa Pires, DDS, PhD Stomatology and Pathology School of Dentistry Estácio de Sá University Av. Alfredo Baltazar da Silveira 580 cobertura Recreio dos Bandeirantes CEP: 22790-701 Rio de Janeiro/RJ, Brazil [email protected]