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Choristoma of the parotid gland
Otolaryngology–Head and Neck Surgery (2009) 140, 767-768
CASE REPORT
Choristoma of the parotid gland Elif Aksoy, MD, Baris Karakullukçu, MD, Nazim Korkut, and ¨ mit Ince, MD, Hague, Istanbul, Turkey U
S
quamous cells might be encountered in a number of salivary gland disorders. However, benign neoplasms that mainly consist of squamous cells are rarely encountered, and they are neither listed in the World Health Organization (WHO) histologic typing of salivary gland tumors1 nor mentioned in major reference books.2 Seifert et al3 presented an unusual benign tumor of the parotid gland that consisted of mainly multilayer squamous cells lining cystic spaces filled with horn like material, namely keratotic lamellas. They defined this tumor as a choristoma, resembling a trichoadenoma. This was the first definition of such a tumor in the literature. Nagao et al4 screened retrospectively 1,921 cases of primary parotid tumors and found 2 cases resembling the one described by Seifert et al. Because of the histologic features, they proposed a new name for the entity: keratocytoma. Choristoma by definition is a tumorlike mass consisting of normal cells in an abnormal location.5 Nagao et al proposed that the tumors they present are primary tumors of parotid epithelial origin rather than choristomas. We are presenting a parotid tumor with similar histolologic features to the previously mentioned choristoma or keratocytomas. The ethical committee of the Acibadem Hospital was contacted, and the permit was waived because case reports do not need to be reviewed. A 28-year-old woman presented with a painless swelling in the left parotid gland for 6 months. Clinical evaluation was consistent with a nontender well-defined mass of a 2.5-cm diameter in the left parotid. Magnetic resonance imaging revealed a cystic mass within the left parotid gland and multiple lymph nodes in the left neck. Fine-needle aspiration biopsy was nondefinitive. Left superficial parotidectomy and selective neck dissection were performed. Histologic evaluation of the specimen revealed a cyst lined with keratinized squamous epithelum. Islands of sebaceous gland lobules, ecrine glands, hyalene cartilage, and striated muscle were present deep to the the squamous epithelium. Wide areas of fatty necrosis, lipogranulomas, and foreign-body reaction were observed surrounding the cyst (Figs 1 and 2). The histology was considered to be consistent with choristoma. Fourteen lymph nodes were identified in the neck dissection specimen. All were consistent with reactive
Figure 1 Salivary gland and the cystic structure lined with squamous cell epithelium surrounded by cartilage and glandular structures (H&E stain, ⫻10).
lymph nodes. The patient has been followed for 16 months without any recurrence.
DISCUSSION The presented tumor has similar histologic characteristics as the choristoma presented by Seifert et al.4 This tumor may originate from the ectodermal oral or salivary epithelium. However, the presented case is a teratomatous structure that should not be present in a major salivary gland. The presence of a squamous epithelial lining surrounded by sebaceous glands, eccrine glands, hyalene cartilage, and striated muscle supports the diagnosis of choristoma. Differential diagnosis includes metastatic squamous cell carcinoma, mucoepidermoid carcinoma, squamous metaplasia of pleomorphic adenoma, and other benign salivary gland tumors. The absence of invasive character, perineural or intravascular extension, necrosis, and atypia helps to diffentiate this type of tumor from carcinomas. Mitotic figures were rare and confined to the inner layer of the epithelium. All evidence supports a structure composed of normal functioning cells
Received August 5, 2008; revised September 11, 2008; accepted September 18, 2008.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2008.09.030
768
Otolaryngology–Head and Neck Surgery, Vol 140, No 5, May 2009
AUTHOR INFORMATION From the Department of Otolaryngology–Head and Neck Surgery, Acibadem Bakirkoy Hospital (Drs Aksoy and Karakullukçu); Department of Otolaryngology–Head and Neck Surgery, Istanbul University Cerrahpasa Medical Faculty (Dr Korkut); and Department of Pathology, Acibadem Hospital (Dr Ince). Corresponding author: Baris Karakullukçu, MD, De Perponcherstraat 77, 2518SP The Hague, Netherlands. E-mail address: [email protected].
AUTHOR CONTRIBUTIONS
Figure 2 Cyst epithelium is similar to epidermis; central sebaceous glands are surrounded by cartilagenous tissue (H&E stain, ⫻40).
present at an abnormal location. The name keratocytoma excludes the accompanying structures such as cartilage and glands present in the structure. Therefore, we elected to use choristoma to name the structure presented. Choristomas are benign processes. Surgical excision is theoretically sufficient for cure. The absence of any neoplastic charasteristics obviates the need for any further treatment. The neck dissection performed for the present case was uncessary and was performed because of the presence of multiple cervical lymph nodes in the absence of a cytologic diagnosis. Choristomas of other regions were treated successfully with limited resections. However, choristomas of the parotid gland are extremely rare, and sufficient data for long-term results are absent. As the number of reports grow, a meta-analysis can reveal the treatment strategy and long-term results.
Elif Aksoy, data collection, writer, part of the team that performed the surgery; Baris Karakullukçu, data collection, writer, part of the team that performed the surgery; Nazim Korkut, data collection, writer, part of the ¨ mit Ince, histopathologic evaluation of team that performed the surgery; U the lesion.
FINANCIAL DISCLOSURE None.
REFERENCES 1. Seifert G, Sobin L. Histological typing of salivary gland tumors (World Health Organization). 2nd ed. New York: Springer-Verlag; 1991. 2. Ellis GL, Aclair PL. Tumors of the salivary glands.Washington DC: Armed Forces Institute of Pathology; 1996. 3. Seifert G, Donath K, Jautzke G. Unusual choristoma of the parotid gland in a girl. A possible tricoadenoma. Virchows Arch 1998;434: 355–9. 4. Nagao T, Serizawa H, Iwaya K. Keratocystoma of the parotid gland: a report of two cases of an unusual pathologic entity. Mod Pathol 2002; 15:1005–10. 5. Kumar V, Fausto N, Abbas A. Neoplasia. Robbins pathologic basis of disease. 7th ed. Philadelphia: WB Saunders; 2004.
CASE REPORT
Choristoma of the parotid gland Elif Aksoy, MD, Baris Karakullukçu, MD, Nazim Korkut, and ¨ mit Ince, MD, Hague, Istanbul, Turkey U
S
quamous cells might be encountered in a number of salivary gland disorders. However, benign neoplasms that mainly consist of squamous cells are rarely encountered, and they are neither listed in the World Health Organization (WHO) histologic typing of salivary gland tumors1 nor mentioned in major reference books.2 Seifert et al3 presented an unusual benign tumor of the parotid gland that consisted of mainly multilayer squamous cells lining cystic spaces filled with horn like material, namely keratotic lamellas. They defined this tumor as a choristoma, resembling a trichoadenoma. This was the first definition of such a tumor in the literature. Nagao et al4 screened retrospectively 1,921 cases of primary parotid tumors and found 2 cases resembling the one described by Seifert et al. Because of the histologic features, they proposed a new name for the entity: keratocytoma. Choristoma by definition is a tumorlike mass consisting of normal cells in an abnormal location.5 Nagao et al proposed that the tumors they present are primary tumors of parotid epithelial origin rather than choristomas. We are presenting a parotid tumor with similar histolologic features to the previously mentioned choristoma or keratocytomas. The ethical committee of the Acibadem Hospital was contacted, and the permit was waived because case reports do not need to be reviewed. A 28-year-old woman presented with a painless swelling in the left parotid gland for 6 months. Clinical evaluation was consistent with a nontender well-defined mass of a 2.5-cm diameter in the left parotid. Magnetic resonance imaging revealed a cystic mass within the left parotid gland and multiple lymph nodes in the left neck. Fine-needle aspiration biopsy was nondefinitive. Left superficial parotidectomy and selective neck dissection were performed. Histologic evaluation of the specimen revealed a cyst lined with keratinized squamous epithelum. Islands of sebaceous gland lobules, ecrine glands, hyalene cartilage, and striated muscle were present deep to the the squamous epithelium. Wide areas of fatty necrosis, lipogranulomas, and foreign-body reaction were observed surrounding the cyst (Figs 1 and 2). The histology was considered to be consistent with choristoma. Fourteen lymph nodes were identified in the neck dissection specimen. All were consistent with reactive
Figure 1 Salivary gland and the cystic structure lined with squamous cell epithelium surrounded by cartilage and glandular structures (H&E stain, ⫻10).
lymph nodes. The patient has been followed for 16 months without any recurrence.
DISCUSSION The presented tumor has similar histologic characteristics as the choristoma presented by Seifert et al.4 This tumor may originate from the ectodermal oral or salivary epithelium. However, the presented case is a teratomatous structure that should not be present in a major salivary gland. The presence of a squamous epithelial lining surrounded by sebaceous glands, eccrine glands, hyalene cartilage, and striated muscle supports the diagnosis of choristoma. Differential diagnosis includes metastatic squamous cell carcinoma, mucoepidermoid carcinoma, squamous metaplasia of pleomorphic adenoma, and other benign salivary gland tumors. The absence of invasive character, perineural or intravascular extension, necrosis, and atypia helps to diffentiate this type of tumor from carcinomas. Mitotic figures were rare and confined to the inner layer of the epithelium. All evidence supports a structure composed of normal functioning cells
Received August 5, 2008; revised September 11, 2008; accepted September 18, 2008.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2008.09.030
768
Otolaryngology–Head and Neck Surgery, Vol 140, No 5, May 2009
AUTHOR INFORMATION From the Department of Otolaryngology–Head and Neck Surgery, Acibadem Bakirkoy Hospital (Drs Aksoy and Karakullukçu); Department of Otolaryngology–Head and Neck Surgery, Istanbul University Cerrahpasa Medical Faculty (Dr Korkut); and Department of Pathology, Acibadem Hospital (Dr Ince). Corresponding author: Baris Karakullukçu, MD, De Perponcherstraat 77, 2518SP The Hague, Netherlands. E-mail address: [email protected].
AUTHOR CONTRIBUTIONS
Figure 2 Cyst epithelium is similar to epidermis; central sebaceous glands are surrounded by cartilagenous tissue (H&E stain, ⫻40).
present at an abnormal location. The name keratocytoma excludes the accompanying structures such as cartilage and glands present in the structure. Therefore, we elected to use choristoma to name the structure presented. Choristomas are benign processes. Surgical excision is theoretically sufficient for cure. The absence of any neoplastic charasteristics obviates the need for any further treatment. The neck dissection performed for the present case was uncessary and was performed because of the presence of multiple cervical lymph nodes in the absence of a cytologic diagnosis. Choristomas of other regions were treated successfully with limited resections. However, choristomas of the parotid gland are extremely rare, and sufficient data for long-term results are absent. As the number of reports grow, a meta-analysis can reveal the treatment strategy and long-term results.
Elif Aksoy, data collection, writer, part of the team that performed the surgery; Baris Karakullukçu, data collection, writer, part of the team that performed the surgery; Nazim Korkut, data collection, writer, part of the ¨ mit Ince, histopathologic evaluation of team that performed the surgery; U the lesion.
FINANCIAL DISCLOSURE None.
REFERENCES 1. Seifert G, Sobin L. Histological typing of salivary gland tumors (World Health Organization). 2nd ed. New York: Springer-Verlag; 1991. 2. Ellis GL, Aclair PL. Tumors of the salivary glands.Washington DC: Armed Forces Institute of Pathology; 1996. 3. Seifert G, Donath K, Jautzke G. Unusual choristoma of the parotid gland in a girl. A possible tricoadenoma. Virchows Arch 1998;434: 355–9. 4. Nagao T, Serizawa H, Iwaya K. Keratocystoma of the parotid gland: a report of two cases of an unusual pathologic entity. Mod Pathol 2002; 15:1005–10. 5. Kumar V, Fausto N, Abbas A. Neoplasia. Robbins pathologic basis of disease. 7th ed. Philadelphia: WB Saunders; 2004.