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Sialoblastoma: a congenital epithelial tumor of the salivary gland
Journal of Pediatric Surgery (2006) 41, 1322 – 1325
www.elsevier.com/locate/jpedsurg
Sialoblastoma: a congenital epithelial tumor of the salivary gland Soner Tatlidedea,*, Semra Karsidaga, Kemal Ugurlua, Bugra Sadikoglua, Canan Tanikb, Lu¨tfu¨ Basa a
Department of Plastic and Reconstructive Surgery, Sisli Etfal Research and Educational Hospital, 34360 Istanbul, Turkey Department of Pathology, Sisli Etfal Research and Educational Hospital, 34360 Istanbul, Turkey
b
Index words: Sialoblastoma; Recurrence; Treatment
Abstract Sialoblastoma is a rare congenital epithelial tumor of the salivary gland that is diagnosed at birth or shortly thereafter with significant variability in histologic range and clinical course; hence, for an individual case, it may be difficult to predict the most appropriate therapy [Cancer 1972;30:459- 69; Pediatr Pathol 1988;8:447- 52; Br J Plast Surg 2000;53(8):697-699]. We report the case of a 4-year-old girl who had a widely spreading sialoblastoma of the left cheek. We were obligated to widely resect the tumor including the trunk of the facial nerve, superior part of the left maxilla, and the zygoma. Although the patient was operated 3 times in 4 years, invasion of the tumor could not be stopped. The patient died because of respiratory insufficiency and deterioration of her general health. D 2006 Elsevier Inc. All rights reserved.
Sialoblastoma, which is also called bembryoma,Q represents a neoplastic proliferation of cells of organ rudiments [1], and it is the most frequent type of congenital epithelial tumor of the salivary glands [2]. Sialoblastoma have been reported to occur predominantly in the parotid gland and very rarely in the submandibular gland [3]. Although it is a slowly spreading tumor, late diagnosis can cause the tumor to spread widely and enlarge the limits of the operation to resect the tumor [1,4].
1. Case report We report the case of a 4-year-old girl. First, her mother noticed a soft, 2-cm mass in the left cheek at the age of 1. When she was admitted to another plastic surgery clinic, her * Corresponding author. Sqbyan Mektep Sokak, 14/3 Yesilkfy, 34149 Istanbul, Turkey. Tel.: +90 212 225 94 84; fax: +90 212 225 94 84. E-mail address: [email protected] (S. Tatlidede). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.03.040
mother was told that the mass was a benign lesion that was probably a hemangioma, and no treatment was needed until the age of 5; the mass was expected to become smaller and spontaneously resolve eventually. At the age of 3, blunt trauma to the mass caused purplish color changes and some enlargement. When we examined the patient at 4 years of age, the mass was 5 cm in diameter. On examination, the mass was infiltrating the left cheek and elevating the skin overlying it. It was fixed to the maxilla, hard, and lobulated. Two lymph nodes were palpated, 0.5 and 1 cm in diameter, moderately hard, and mobile at the left submandibular region (Fig. 1A, B). Computerized tomography and magnetic resonance imaging (MRI) evaluation showed that the tumor infiltrated the left cheek, maxilla, infraorbital region, zygoma, and left temporal fossa (Fig. 2). We performed an incisional biopsy to the tumor under general anesthesia, and the diagnosis was sialoblastoma. Microscopic evaluation revealed that the tumor mass was surrounded by a tensile, connective tissue and consisted of epithelial cells with small ducts (Fig. 3). The tumor was
Sialoblastoma
Fig. 1
1323
The mass infiltrated the left cheek and elevated the overlying skin. A, Anterior image. B, Lateral image.
resected with the skin (8 cm in diameter), left parotid, superior part of the left maxilla and the left orbital floor, left zygoma, and left buccal mucosa. The part of the tumor infiltrating the temporal fossa through a passage under zygomatic arch was resected with the zygomatic arch as well. The facial nerve was cut before entering the parotid. On frozen section evaluation, margins of the resection were revealed to be tumor-free. Reconstruction was done by a free scapula fasciocutaneous and serratus muscle combined flap while reconstructing the orbital floor by cortical iliac bone graft stabilized by microplates. The left buccal mucosa was formed by the epimysium of the serratus muscle. We have not observed any complication, except partial graft loss at the donor side of the scapular flap. The biopsy specimens were routinely fixed in formaldehyde and embedded in paraffin wax. Several stains were
used, including hematoxylin-eosin (H&E), periodic acidSchiff reaction, and Alcian blue (pH 2.5). In addition, the cases were studied immunohistochemically, by staining for myosin, muscle-specific actin, periodic acid schiff (PAS), cytokeratins, epithelial membrane antigen (EMA), vimetin, S100 protein, and neuron-specific enolase (NSE). H&E– stained sections showed that the tumor was characterized by solid cell nests of epithelial cells intermingled with proliferating ductal structures and multiple trabecular formation. All cells contained small nucleus, eosinophilic cytoplasma with atypia. Both ducts and acini were surrounded by fibrous stroma. These appearances were uniform throughout the lesion; hemorrhage and necrosis were present. Cytokeratin immunoperoxidase staining showed strong positivity off cells forming ductal structures. Antibodies to EMA showed weak staining of ductal tumor
Fig. 2 Sialoblastoma infiltrated the left cheek, maxilla, infraorbital region, zygoma, and left temporal fossa.
Fig. 3 The tumor mass was surrounded by a tensile, connective tissue and consists of epithelial cells with small ducts (H&E, 125).
1324 cells. Smooth muscle antigen (SMA), myosin, and vimetin were demonstrated in the stroma, and staining for S100 protein confirmed the peripheral nerve bundles and myoepithelial cells. After 15 months of follow up, MRI evaluation showed that the tumor had recurred at the left sphenoid bone, optic canal, caverneus sinus, left internal carotid artery, and left middle cranial fossa (Fig. 4). The tumor size was measured 30 13 18 mm with MRI. We planned an operation with neurosurgeons, but we could not perform complete surgical removal. After 21 months, the tumor extended into the left orbit (Fig. 5). After ocular examination, we found the tumor had spread to the third, fourth, sixth cranial nerves, and optic nerve. We guided the patient to an oncology clinic. They began a protocol of chemotherapy that was composed of vincristine (1 g), dactinomycine (0.5 mg), cyclophosphamide (1 g), and mesna (400 mg). This protocol was administrated 3 times with an interval of 1 month in between treatments. During the administration of this protocol, the tumor regression started in the second month. MRI evaluation showed that tumor size was 25 11 13 mm, and regression especially in cavernous sinus had occurred. After 6 months, the girl was hospitalized because the tumor has enlarged gradually and caused pain. On MRI investigation, we observed that the tumor extended to the orbital rim anteriorly, entirely surrounded the internal carotid artery, and went posteriorly in the sellar cavity and left parasellar area, made an impression on the left site of the pons, and extended to the left prepontine cistern. The tumor was partially excised by the neurosurgeons, and we performed orbital exenteration. In the postoperative period, while she was being monitored in the intensive care unit, tonic-clonic contractions and hyponatremia appeared. Sodium replacement and infusion of epdantoin were started. When her general state had improved, she was discharged
Fig. 4 The tumor recurred in the left sphenoid bone, optic canal, cavernous sinus, left internal carotid artery, and left middle cranial fossa.
S. Tatlidede et al.
Fig. 5
The tumor extended into the left orbit.
after 15 days of hospitalization. After 3 months from the last operation, the patient died because of respiratory insufficiency and overall deterioration in her general health.
2. Discussion Tumors of the salivary gland are very uncommon in children [5]. About 3% to 5% of all salivary gland tumors occur in children [4,6]. Congenital epithelial tumors of the salivary gland are extremely rare [1,7], and most of these tumors in children are encountered after 5 years of age [8]. The following 3 types of epithelial tumors can be differentiated: adenomas, sialoblastomas (embryomas), and carcinomas. Sialoblastoma was first reported by Vawter and Tefft [1] in 1966 and was called embryoma [6]. The tumor is locally aggressive, with high recurrence rates. About 25% of the cases are characterized as malignant with elevated mitotic activity and local lymph node metastases [4]. The differential diagnosis is reflected by the names given to this tumor: embryoma of the parotid gland [1,9], congenital basal cell adenoma [10], embryonal carcinoma [11], basoloid monomorphic adenomas [4], and adenoid cystic carcinoma [12]. The primitive appearance of the neoplastic cells, tendency of the tumor to recapitulate the developing parotid gland, and its congenital occurrence, which implies origin from a primitive organ blasteme, strongly suggest that this tumor represents an embryoma of the parotid gland [1]. The sialoblastomas are often mitotically active, primitive cell masses with formative ducts and pseudoductular spaces without acinar differentiation. Their appearance recalls the preacinar stages of morphogenesis [13].
Sialoblastoma Congenital basal cell adenoma showed many similarities to sialoblastoma but showed clear sebaceous differentiation. None of the reports of congenital basal cell adenomas describe the presence of myoepithelial cells [2], but only in the sialoblastoma was a myoepithelial population identified [6]. Embryonal carcinoma consisted of solid and medullary areas, some showing acinar differentiation, with epidermoid foci and keratinization [2]. Basoloid monomorphic adenomas are characterized by prominent peripheral palisading of the nuclei, lack of nuclear pleomorphism or mitotic activity, and a benign, generally nonrecurrent clinical course [4]. The presence of a cribriform pattern developed within solid sheets of cells in adenoid cystic carcinoma is different from sialoblastoma [4]. The authors propose that sialoblastomas should be regarded neither as benign nor malignant but as one single disease with local infiltrative potential [14]. Based on this concept, sialoblastomas can be treated with early conservative surgery alone, provided that free margins are obtained. In our case, after wide complete resection, reconstruction was done by a free combined flap including scapular fasciocutaneous flap and serratus muscle flap on 1 pedicle while reconstructing the orbital floor by a free iliac bone graft. The contour of the left cheek was achieved by the bulkiness of the serratus muscle, and the scapular skin was well adapted to the region with minimal hypopigmentation. By using this flap, both volume and skin deficiency were restored, and less donor area morbidity was created. The buccal mucosa of the left cheek was reconstructed by the epimysium of the serratus muscle, and the buccal mucosa moved over the epimysium and healed in 3 weeks. A review of the literature on sialoblastoma showed that some cases recurred locally [11]. It is not clear why these lesions tend to have local recurrences; however, they are considered locally aggressive, mostly their systemic invasion is not expected. Our patient developed recurrence at the sheath of the left carotid 15 months later and in the left orbit 21 months later. In this stage, we could not perform complete removal. When we researched the literature, we did not find any protocol of chemotherapy for sialoblastoma. Some drugs were administrated to the patient by an oncology clinic, and minimal regression was observed.
1325 In spite of orbital exenteration and partial resection because of reenlargement of tumor, the patient died 3 months after the final operation. Sialoblastoma, a rare tumor of salivary glands, should be included in the differential diagnosis of the childhood facial tumors. The late diagnosis allowed for spreading of the tumor; thus, we performed a wide resection. Despite wide resection, this tumor has high potential of local aggressive recurrences.
References [1] Vawter GF, Tefft M. Congenital tumors of the parotid gland. Arch Pathol 1966;82:242 - 5. [2] Harris MD, Mckeever P, Robertson JM. Congenital tumours of the salivary gland: a case report and review. Histopathology 1990;17: 155 - 7. [3] Mostafapour SP, Folz B, Barlow D, et al. Sialoblastoma of submandibular gland: report of a case and review of the literature. Int J Pediatr Otorhinolaryngol 2000;53(2):157 - 61. [4] Taylor GP. Case 6 congenital epithelial tumor of the parotidsialoblastoma. Pediatr Pathol 1988;8:447 - 52. [5] Garrido A., Humphrey G., Squire R.S., et al. Sialoblastoma. Br J Plast Surg 2000;53(8):697 - 9. [6] Krolls SO, Trodahl J, Boyers RC. Salivary gland lesions in children. A survey of 430 cases. Cancer 1972;30:459 - 69. [7] Tipton JB. Carcinoma of a minor salivary gland in an 18-month-old child. Case reportPlast Reconstr Surg 1978;62:790 - 2. [8] Schuller DE, McCabe BF. Salivary gland neoplasms in children. Otolaryngol Clin North Am 1977;10:399 - 412. [9] Roth A, Micheau C. Embryoma (or embryonal tumour) of the parotid gland: report of two cases. Pediatr Pathol 1986;5:9 - 15. [10] Canalis RF, Mok MW, Fishman SM, et al. Congenital basal cell adenoma of the submandibular gland. Arch Otolaryngol 1980; 106:284 - 6. [11] Donath K, Seifert G, Lentrodt J. The embryonal carcinoma of the parotid gland. A rare example of an embryonal tumour. Virchows Arch A 1984;403:425 - 40. [12] Simpson PR, Rutledge JC, Schaefer SD, et al. Congenital hybrid basal cell adenoma-adenoid cystic carcinoma of the salivary gland. Pediatr Pathol 1986;6:199 - 208. [13] Som PM, Brandwein M, Silvers AR, et al. Sialoblastoma (embriyoma): MR findings of a rare pediatric salivary gland tumor. AJNR Am J Neuroradiol 1997;18:847 - 50. [14] Alvarez-Mendoza A, Calderon-Elvir C, Carrasco-Daza D. Diagnostic and therapeutic approach to sialoblastoma: report of a case. J Pediatr Surg 1999;34(12):1875 - 7.
www.elsevier.com/locate/jpedsurg
Sialoblastoma: a congenital epithelial tumor of the salivary gland Soner Tatlidedea,*, Semra Karsidaga, Kemal Ugurlua, Bugra Sadikoglua, Canan Tanikb, Lu¨tfu¨ Basa a
Department of Plastic and Reconstructive Surgery, Sisli Etfal Research and Educational Hospital, 34360 Istanbul, Turkey Department of Pathology, Sisli Etfal Research and Educational Hospital, 34360 Istanbul, Turkey
b
Index words: Sialoblastoma; Recurrence; Treatment
Abstract Sialoblastoma is a rare congenital epithelial tumor of the salivary gland that is diagnosed at birth or shortly thereafter with significant variability in histologic range and clinical course; hence, for an individual case, it may be difficult to predict the most appropriate therapy [Cancer 1972;30:459- 69; Pediatr Pathol 1988;8:447- 52; Br J Plast Surg 2000;53(8):697-699]. We report the case of a 4-year-old girl who had a widely spreading sialoblastoma of the left cheek. We were obligated to widely resect the tumor including the trunk of the facial nerve, superior part of the left maxilla, and the zygoma. Although the patient was operated 3 times in 4 years, invasion of the tumor could not be stopped. The patient died because of respiratory insufficiency and deterioration of her general health. D 2006 Elsevier Inc. All rights reserved.
Sialoblastoma, which is also called bembryoma,Q represents a neoplastic proliferation of cells of organ rudiments [1], and it is the most frequent type of congenital epithelial tumor of the salivary glands [2]. Sialoblastoma have been reported to occur predominantly in the parotid gland and very rarely in the submandibular gland [3]. Although it is a slowly spreading tumor, late diagnosis can cause the tumor to spread widely and enlarge the limits of the operation to resect the tumor [1,4].
1. Case report We report the case of a 4-year-old girl. First, her mother noticed a soft, 2-cm mass in the left cheek at the age of 1. When she was admitted to another plastic surgery clinic, her * Corresponding author. Sqbyan Mektep Sokak, 14/3 Yesilkfy, 34149 Istanbul, Turkey. Tel.: +90 212 225 94 84; fax: +90 212 225 94 84. E-mail address: [email protected] (S. Tatlidede). 0022-3468/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2006.03.040
mother was told that the mass was a benign lesion that was probably a hemangioma, and no treatment was needed until the age of 5; the mass was expected to become smaller and spontaneously resolve eventually. At the age of 3, blunt trauma to the mass caused purplish color changes and some enlargement. When we examined the patient at 4 years of age, the mass was 5 cm in diameter. On examination, the mass was infiltrating the left cheek and elevating the skin overlying it. It was fixed to the maxilla, hard, and lobulated. Two lymph nodes were palpated, 0.5 and 1 cm in diameter, moderately hard, and mobile at the left submandibular region (Fig. 1A, B). Computerized tomography and magnetic resonance imaging (MRI) evaluation showed that the tumor infiltrated the left cheek, maxilla, infraorbital region, zygoma, and left temporal fossa (Fig. 2). We performed an incisional biopsy to the tumor under general anesthesia, and the diagnosis was sialoblastoma. Microscopic evaluation revealed that the tumor mass was surrounded by a tensile, connective tissue and consisted of epithelial cells with small ducts (Fig. 3). The tumor was
Sialoblastoma
Fig. 1
1323
The mass infiltrated the left cheek and elevated the overlying skin. A, Anterior image. B, Lateral image.
resected with the skin (8 cm in diameter), left parotid, superior part of the left maxilla and the left orbital floor, left zygoma, and left buccal mucosa. The part of the tumor infiltrating the temporal fossa through a passage under zygomatic arch was resected with the zygomatic arch as well. The facial nerve was cut before entering the parotid. On frozen section evaluation, margins of the resection were revealed to be tumor-free. Reconstruction was done by a free scapula fasciocutaneous and serratus muscle combined flap while reconstructing the orbital floor by cortical iliac bone graft stabilized by microplates. The left buccal mucosa was formed by the epimysium of the serratus muscle. We have not observed any complication, except partial graft loss at the donor side of the scapular flap. The biopsy specimens were routinely fixed in formaldehyde and embedded in paraffin wax. Several stains were
used, including hematoxylin-eosin (H&E), periodic acidSchiff reaction, and Alcian blue (pH 2.5). In addition, the cases were studied immunohistochemically, by staining for myosin, muscle-specific actin, periodic acid schiff (PAS), cytokeratins, epithelial membrane antigen (EMA), vimetin, S100 protein, and neuron-specific enolase (NSE). H&E– stained sections showed that the tumor was characterized by solid cell nests of epithelial cells intermingled with proliferating ductal structures and multiple trabecular formation. All cells contained small nucleus, eosinophilic cytoplasma with atypia. Both ducts and acini were surrounded by fibrous stroma. These appearances were uniform throughout the lesion; hemorrhage and necrosis were present. Cytokeratin immunoperoxidase staining showed strong positivity off cells forming ductal structures. Antibodies to EMA showed weak staining of ductal tumor
Fig. 2 Sialoblastoma infiltrated the left cheek, maxilla, infraorbital region, zygoma, and left temporal fossa.
Fig. 3 The tumor mass was surrounded by a tensile, connective tissue and consists of epithelial cells with small ducts (H&E, 125).
1324 cells. Smooth muscle antigen (SMA), myosin, and vimetin were demonstrated in the stroma, and staining for S100 protein confirmed the peripheral nerve bundles and myoepithelial cells. After 15 months of follow up, MRI evaluation showed that the tumor had recurred at the left sphenoid bone, optic canal, caverneus sinus, left internal carotid artery, and left middle cranial fossa (Fig. 4). The tumor size was measured 30 13 18 mm with MRI. We planned an operation with neurosurgeons, but we could not perform complete surgical removal. After 21 months, the tumor extended into the left orbit (Fig. 5). After ocular examination, we found the tumor had spread to the third, fourth, sixth cranial nerves, and optic nerve. We guided the patient to an oncology clinic. They began a protocol of chemotherapy that was composed of vincristine (1 g), dactinomycine (0.5 mg), cyclophosphamide (1 g), and mesna (400 mg). This protocol was administrated 3 times with an interval of 1 month in between treatments. During the administration of this protocol, the tumor regression started in the second month. MRI evaluation showed that tumor size was 25 11 13 mm, and regression especially in cavernous sinus had occurred. After 6 months, the girl was hospitalized because the tumor has enlarged gradually and caused pain. On MRI investigation, we observed that the tumor extended to the orbital rim anteriorly, entirely surrounded the internal carotid artery, and went posteriorly in the sellar cavity and left parasellar area, made an impression on the left site of the pons, and extended to the left prepontine cistern. The tumor was partially excised by the neurosurgeons, and we performed orbital exenteration. In the postoperative period, while she was being monitored in the intensive care unit, tonic-clonic contractions and hyponatremia appeared. Sodium replacement and infusion of epdantoin were started. When her general state had improved, she was discharged
Fig. 4 The tumor recurred in the left sphenoid bone, optic canal, cavernous sinus, left internal carotid artery, and left middle cranial fossa.
S. Tatlidede et al.
Fig. 5
The tumor extended into the left orbit.
after 15 days of hospitalization. After 3 months from the last operation, the patient died because of respiratory insufficiency and overall deterioration in her general health.
2. Discussion Tumors of the salivary gland are very uncommon in children [5]. About 3% to 5% of all salivary gland tumors occur in children [4,6]. Congenital epithelial tumors of the salivary gland are extremely rare [1,7], and most of these tumors in children are encountered after 5 years of age [8]. The following 3 types of epithelial tumors can be differentiated: adenomas, sialoblastomas (embryomas), and carcinomas. Sialoblastoma was first reported by Vawter and Tefft [1] in 1966 and was called embryoma [6]. The tumor is locally aggressive, with high recurrence rates. About 25% of the cases are characterized as malignant with elevated mitotic activity and local lymph node metastases [4]. The differential diagnosis is reflected by the names given to this tumor: embryoma of the parotid gland [1,9], congenital basal cell adenoma [10], embryonal carcinoma [11], basoloid monomorphic adenomas [4], and adenoid cystic carcinoma [12]. The primitive appearance of the neoplastic cells, tendency of the tumor to recapitulate the developing parotid gland, and its congenital occurrence, which implies origin from a primitive organ blasteme, strongly suggest that this tumor represents an embryoma of the parotid gland [1]. The sialoblastomas are often mitotically active, primitive cell masses with formative ducts and pseudoductular spaces without acinar differentiation. Their appearance recalls the preacinar stages of morphogenesis [13].
Sialoblastoma Congenital basal cell adenoma showed many similarities to sialoblastoma but showed clear sebaceous differentiation. None of the reports of congenital basal cell adenomas describe the presence of myoepithelial cells [2], but only in the sialoblastoma was a myoepithelial population identified [6]. Embryonal carcinoma consisted of solid and medullary areas, some showing acinar differentiation, with epidermoid foci and keratinization [2]. Basoloid monomorphic adenomas are characterized by prominent peripheral palisading of the nuclei, lack of nuclear pleomorphism or mitotic activity, and a benign, generally nonrecurrent clinical course [4]. The presence of a cribriform pattern developed within solid sheets of cells in adenoid cystic carcinoma is different from sialoblastoma [4]. The authors propose that sialoblastomas should be regarded neither as benign nor malignant but as one single disease with local infiltrative potential [14]. Based on this concept, sialoblastomas can be treated with early conservative surgery alone, provided that free margins are obtained. In our case, after wide complete resection, reconstruction was done by a free combined flap including scapular fasciocutaneous flap and serratus muscle flap on 1 pedicle while reconstructing the orbital floor by a free iliac bone graft. The contour of the left cheek was achieved by the bulkiness of the serratus muscle, and the scapular skin was well adapted to the region with minimal hypopigmentation. By using this flap, both volume and skin deficiency were restored, and less donor area morbidity was created. The buccal mucosa of the left cheek was reconstructed by the epimysium of the serratus muscle, and the buccal mucosa moved over the epimysium and healed in 3 weeks. A review of the literature on sialoblastoma showed that some cases recurred locally [11]. It is not clear why these lesions tend to have local recurrences; however, they are considered locally aggressive, mostly their systemic invasion is not expected. Our patient developed recurrence at the sheath of the left carotid 15 months later and in the left orbit 21 months later. In this stage, we could not perform complete removal. When we researched the literature, we did not find any protocol of chemotherapy for sialoblastoma. Some drugs were administrated to the patient by an oncology clinic, and minimal regression was observed.
1325 In spite of orbital exenteration and partial resection because of reenlargement of tumor, the patient died 3 months after the final operation. Sialoblastoma, a rare tumor of salivary glands, should be included in the differential diagnosis of the childhood facial tumors. The late diagnosis allowed for spreading of the tumor; thus, we performed a wide resection. Despite wide resection, this tumor has high potential of local aggressive recurrences.
References [1] Vawter GF, Tefft M. Congenital tumors of the parotid gland. Arch Pathol 1966;82:242 - 5. [2] Harris MD, Mckeever P, Robertson JM. Congenital tumours of the salivary gland: a case report and review. Histopathology 1990;17: 155 - 7. [3] Mostafapour SP, Folz B, Barlow D, et al. Sialoblastoma of submandibular gland: report of a case and review of the literature. Int J Pediatr Otorhinolaryngol 2000;53(2):157 - 61. [4] Taylor GP. Case 6 congenital epithelial tumor of the parotidsialoblastoma. Pediatr Pathol 1988;8:447 - 52. [5] Garrido A., Humphrey G., Squire R.S., et al. Sialoblastoma. Br J Plast Surg 2000;53(8):697 - 9. [6] Krolls SO, Trodahl J, Boyers RC. Salivary gland lesions in children. A survey of 430 cases. Cancer 1972;30:459 - 69. [7] Tipton JB. Carcinoma of a minor salivary gland in an 18-month-old child. Case reportPlast Reconstr Surg 1978;62:790 - 2. [8] Schuller DE, McCabe BF. Salivary gland neoplasms in children. Otolaryngol Clin North Am 1977;10:399 - 412. [9] Roth A, Micheau C. Embryoma (or embryonal tumour) of the parotid gland: report of two cases. Pediatr Pathol 1986;5:9 - 15. [10] Canalis RF, Mok MW, Fishman SM, et al. Congenital basal cell adenoma of the submandibular gland. Arch Otolaryngol 1980; 106:284 - 6. [11] Donath K, Seifert G, Lentrodt J. The embryonal carcinoma of the parotid gland. A rare example of an embryonal tumour. Virchows Arch A 1984;403:425 - 40. [12] Simpson PR, Rutledge JC, Schaefer SD, et al. Congenital hybrid basal cell adenoma-adenoid cystic carcinoma of the salivary gland. Pediatr Pathol 1986;6:199 - 208. [13] Som PM, Brandwein M, Silvers AR, et al. Sialoblastoma (embriyoma): MR findings of a rare pediatric salivary gland tumor. AJNR Am J Neuroradiol 1997;18:847 - 50. [14] Alvarez-Mendoza A, Calderon-Elvir C, Carrasco-Daza D. Diagnostic and therapeutic approach to sialoblastoma: report of a case. J Pediatr Surg 1999;34(12):1875 - 7.