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Hamartomatous sialolipoma of the submandibular gland: case report
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British Journal of Oral and Maxillofacial Surgery 46 (2008) 599–600
Short communication
Hamartomatous sialolipoma of the submandibular gland: case report Paola Parente a , Gianluigi Longobardi b , Giulio Bigotti a,∗ a b
Department of Anatomic Pathology, Catholic University of Sacred Heart, Largo F. Vito 1, 00168 Rome, Italy Department of Maxillofacial Surgery, Catholic University of Sacred Heart, Columbus Clinic, Rome, Italy
Accepted 11 February 2008 Available online 18 April 2008
Abstract Sialolipoma is a rare tumour of the salivary gland that is composed of mature adipocytes and normal salivary gland tissue. We report an unusual case of a sialolipoma of the submandibular gland in a 77-year-old woman. The location of this tumour has not to our knowledge been previously described. The tumour was excised and has not recurred during 22 months postoperatively. © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Sialolipoma; Lipoma; Hamartoma; Submandibular gland
Introduction In 2001 Nagao et al. proposed the term “sialolipoma” to describe a distinct type of lipoma of the salivary gland that is composed of mature adipocytes and normal salivary gland tissue.1 We have been able to find only 17 similar case reports of this rare tumour in the English language.2–9
Case report A 77-year-old woman was referred to our unit for investigation of a painless swelling in the right submandibular region that had been present for some months. Clinically, the swelling looked well-defined and was mobile. The patient’s medical history was unremarkable. The tumour was completely excised, and her postoperative recovery was uneventful; the tumour had not recurred during the 22 months postoperatively. Macroscopically, the specimen measured 30 × 20 × 18 mm, and the cut surface was soft and yellowish. Histolog∗
Corresponding author. Tel.: +39 6 30154270; fax: +39 6 3054641. E-mail address: [email protected] (G. Bigotti).
ically the mass, completely surrounded by a delicate fibrous capsule, consisted of mature adipocytes and normal salivary gland tissue. The lipomatous tissue made up 80% of the total mass of the tumour, while the remainder consisted of salivary gland tissue, unusual, tortuous, thick vessels of arterial and venous calibre, similar to those seen in arterio-venous malformation, and numerous nerve fibres (Fig. 1). There were no mitoses or atypia. The tumour contained acinar oncocytic metaplasia (Fig. 2), fibrosis, ductal ectasia, and inflammation. Immunohistochemically, the epithelial cells stained for cytokeratins AE1/3 and 14, and for EMA. Myoepithelial cells were identified by staining for ␣-smooth muscle actin and S-100 protein. The overall appearance of the tumour was compatible with that of a sialolipoma. However, a hamartoma could not be definitively ruled out, given the intimate admixture of thick abnormal vessels, nerve fibres, and salivary gland and fatty tissue within the tumour.
Discussion Sialolipomas are rare, and we have found only 17 case reports in English.2–9 These comprised 17 patients (7 men and 8
0266-4356/$ – see front matter © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.02.006
600
P. Parente et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 599–600
Fig. 1. Peripheral area of the tumour surrounded by a thin fibrous capsule and showing unusual tortuous thick vessels (haematoxylin and eosin, original magnification × 10).
hamartomatous histogenesis. Our report may also be the first description of this tumour developing in the submandibular gland. As mature lipomas, sialolipomas are benign, slowlygrowing tumours. In all previous reports, the patients were treated by complete excision of the tumour, which did not recur. It is likely that a sialolipoma, which is well-recognised and classified as a distinct salivary gland neoplasm,10 may be more commonly reported. The differential diagnosis of sialolipoma includes lipomatosis or fatty replacement, lipomatous pleomorphic adenoma, lipoadenoma and hamartoma. Nagao et al. hypothesised that the glandular component of sialolipoma could be normal salivary gland tissue,1 but the true pathogenesis of this rare tumour is still unknown. The peculiar histological appearance of our tumour suggests that the acinar and ductal components are not merely entrapped salivary gland tissue, but rather the elements of a hamartomatous (malformative) process.
Acknowledgements We thank Dr. Sandra Pasquini for laboratory assistance.
References
Fig. 2. Normal salivary gland tissue with acinar oncocytic metaplasia evident within the lesion (haematoxylin and eosin, original magnification × 20).
women; age range, from newborn to 84 years). Nine cases were localised in the parotid gland and 8 in a minor salivary gland. The tumours ranged in size from 1 to 6 cm. Sialolipoma is a tumour that is composed of mature adipocytes and normal salivary gland elements. In addition to these characteristic features, there was disorganised proliferation of vascular and nervous structures in the stroma of the tumour. This finding has to our knowledge not been reported previously in a sialolipoma and suggests a possible
1. Nagao T, Sugano I, Ishida Y, et al. Sialolipoma: a report of seven cases of a new variant of salivary gland lipoma. Histopathology 2001;38:30–6. 2. Fregnani ER, Pires FR, Falzoni R, Lopes MA, Vargas PA. Lipomas of the oral cavity: clinical findings, histological classification and proliferative activity of 46 cases. Int J Oral Maxillofac Surg 2003;32:49–53. 3. Lin YJ, Lin LM, Chen YK, et al. Sialolipoma of the floor of the mouth: a case report. Kaohsiung J Med Sci 2004;20:410–4. 4. Hornigold R, Morgan PR, Pearce A, Gleeson MJ. Congenital sialolipoma of the parotid gland first reported case and review of the literature. Int J Pediatr Otorhinolaryngol 2005;69:429–34. 5. Michaelidis IGA, Stefanopoulos PK, Sambaziotis D, Zahos MA, Papadimitriou GA. Sialolipoma of the parotid gland. J Craniomaxillofac Surg 2006;34:43–6. 6. Sakai T, Iida S, Kishino M, Okura M, Kogo M. Sialolipoma of the hard palate. J Oral Pathol Med 2006;35:376–8. 7. Bansal B, Ramavat AS, Gupta S, et al. Congenital sialolipoma of parotid gland: a report of rare and recently described entity with review of literature. Pediatr Dev Pathol 2007;10:244–6. 8. Kadivar M, Shahzadi SZ, Javadi M. Sialolipoma of the parotid gland with diffuse sebaceous differentiation in a female child. Pediatr Dev Pathol 2007;10:138–41. 9. Ramer N, Lumerman HS, Ramer Y. Sialolipoma: report of two cases and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:809–13. 10. Rosai J, editor. Rosai and Ackerman’s surgical pathology, vol. 1, 9th ed. St Louis: Mosby; 2004. p. 897.
British Journal of Oral and Maxillofacial Surgery 46 (2008) 599–600
Short communication
Hamartomatous sialolipoma of the submandibular gland: case report Paola Parente a , Gianluigi Longobardi b , Giulio Bigotti a,∗ a b
Department of Anatomic Pathology, Catholic University of Sacred Heart, Largo F. Vito 1, 00168 Rome, Italy Department of Maxillofacial Surgery, Catholic University of Sacred Heart, Columbus Clinic, Rome, Italy
Accepted 11 February 2008 Available online 18 April 2008
Abstract Sialolipoma is a rare tumour of the salivary gland that is composed of mature adipocytes and normal salivary gland tissue. We report an unusual case of a sialolipoma of the submandibular gland in a 77-year-old woman. The location of this tumour has not to our knowledge been previously described. The tumour was excised and has not recurred during 22 months postoperatively. © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Sialolipoma; Lipoma; Hamartoma; Submandibular gland
Introduction In 2001 Nagao et al. proposed the term “sialolipoma” to describe a distinct type of lipoma of the salivary gland that is composed of mature adipocytes and normal salivary gland tissue.1 We have been able to find only 17 similar case reports of this rare tumour in the English language.2–9
Case report A 77-year-old woman was referred to our unit for investigation of a painless swelling in the right submandibular region that had been present for some months. Clinically, the swelling looked well-defined and was mobile. The patient’s medical history was unremarkable. The tumour was completely excised, and her postoperative recovery was uneventful; the tumour had not recurred during the 22 months postoperatively. Macroscopically, the specimen measured 30 × 20 × 18 mm, and the cut surface was soft and yellowish. Histolog∗
Corresponding author. Tel.: +39 6 30154270; fax: +39 6 3054641. E-mail address: [email protected] (G. Bigotti).
ically the mass, completely surrounded by a delicate fibrous capsule, consisted of mature adipocytes and normal salivary gland tissue. The lipomatous tissue made up 80% of the total mass of the tumour, while the remainder consisted of salivary gland tissue, unusual, tortuous, thick vessels of arterial and venous calibre, similar to those seen in arterio-venous malformation, and numerous nerve fibres (Fig. 1). There were no mitoses or atypia. The tumour contained acinar oncocytic metaplasia (Fig. 2), fibrosis, ductal ectasia, and inflammation. Immunohistochemically, the epithelial cells stained for cytokeratins AE1/3 and 14, and for EMA. Myoepithelial cells were identified by staining for ␣-smooth muscle actin and S-100 protein. The overall appearance of the tumour was compatible with that of a sialolipoma. However, a hamartoma could not be definitively ruled out, given the intimate admixture of thick abnormal vessels, nerve fibres, and salivary gland and fatty tissue within the tumour.
Discussion Sialolipomas are rare, and we have found only 17 case reports in English.2–9 These comprised 17 patients (7 men and 8
0266-4356/$ – see front matter © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.02.006
600
P. Parente et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 599–600
Fig. 1. Peripheral area of the tumour surrounded by a thin fibrous capsule and showing unusual tortuous thick vessels (haematoxylin and eosin, original magnification × 10).
hamartomatous histogenesis. Our report may also be the first description of this tumour developing in the submandibular gland. As mature lipomas, sialolipomas are benign, slowlygrowing tumours. In all previous reports, the patients were treated by complete excision of the tumour, which did not recur. It is likely that a sialolipoma, which is well-recognised and classified as a distinct salivary gland neoplasm,10 may be more commonly reported. The differential diagnosis of sialolipoma includes lipomatosis or fatty replacement, lipomatous pleomorphic adenoma, lipoadenoma and hamartoma. Nagao et al. hypothesised that the glandular component of sialolipoma could be normal salivary gland tissue,1 but the true pathogenesis of this rare tumour is still unknown. The peculiar histological appearance of our tumour suggests that the acinar and ductal components are not merely entrapped salivary gland tissue, but rather the elements of a hamartomatous (malformative) process.
Acknowledgements We thank Dr. Sandra Pasquini for laboratory assistance.
References
Fig. 2. Normal salivary gland tissue with acinar oncocytic metaplasia evident within the lesion (haematoxylin and eosin, original magnification × 20).
women; age range, from newborn to 84 years). Nine cases were localised in the parotid gland and 8 in a minor salivary gland. The tumours ranged in size from 1 to 6 cm. Sialolipoma is a tumour that is composed of mature adipocytes and normal salivary gland elements. In addition to these characteristic features, there was disorganised proliferation of vascular and nervous structures in the stroma of the tumour. This finding has to our knowledge not been reported previously in a sialolipoma and suggests a possible
1. Nagao T, Sugano I, Ishida Y, et al. Sialolipoma: a report of seven cases of a new variant of salivary gland lipoma. Histopathology 2001;38:30–6. 2. Fregnani ER, Pires FR, Falzoni R, Lopes MA, Vargas PA. Lipomas of the oral cavity: clinical findings, histological classification and proliferative activity of 46 cases. Int J Oral Maxillofac Surg 2003;32:49–53. 3. Lin YJ, Lin LM, Chen YK, et al. Sialolipoma of the floor of the mouth: a case report. Kaohsiung J Med Sci 2004;20:410–4. 4. Hornigold R, Morgan PR, Pearce A, Gleeson MJ. Congenital sialolipoma of the parotid gland first reported case and review of the literature. Int J Pediatr Otorhinolaryngol 2005;69:429–34. 5. Michaelidis IGA, Stefanopoulos PK, Sambaziotis D, Zahos MA, Papadimitriou GA. Sialolipoma of the parotid gland. J Craniomaxillofac Surg 2006;34:43–6. 6. Sakai T, Iida S, Kishino M, Okura M, Kogo M. Sialolipoma of the hard palate. J Oral Pathol Med 2006;35:376–8. 7. Bansal B, Ramavat AS, Gupta S, et al. Congenital sialolipoma of parotid gland: a report of rare and recently described entity with review of literature. Pediatr Dev Pathol 2007;10:244–6. 8. Kadivar M, Shahzadi SZ, Javadi M. Sialolipoma of the parotid gland with diffuse sebaceous differentiation in a female child. Pediatr Dev Pathol 2007;10:138–41. 9. Ramer N, Lumerman HS, Ramer Y. Sialolipoma: report of two cases and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:809–13. 10. Rosai J, editor. Rosai and Ackerman’s surgical pathology, vol. 1, 9th ed. St Louis: Mosby; 2004. p. 897.