Sialoblastoma of the submandibular gland: a distinct entity?

Sialoblastoma is a rare congenital malignant tumor of the salivary glands. A case of a submandibular sialoblastoma in a 1.5-year-old child is presented. A comparative analysis on 79 pediatric cases reported in the literature suggests a less aggressive behavior for submandibular sialoblastoma in comparison with other sites. Classically, diagnosis is confirmed by open biopsy, but fine-needle aspiration may offer an alternative with reduced morbidity. Expression of AFP and high levels of Ki-67 have been associated with poor prognosis. Whilst early surgical resection with negative margins is widely accepted as first-line treatment, there is no consensus on therapy of recurrence and follow-up. MRI and sonography represent valid tools for the follow-up, which is usually restricted to 3-5 years.Conclusion: Submandibular sialoblastomas may have a different biological profile in comparison with parotid tumors with the absence of metastasis and much lower rate of recurrence. Comprehensive diagnostics should include additional options such as fine-needle aspiration and markers to assess cell proliferation and AFP. Literature suggests that surgery alone is sufficient for the treatment of tumors with low malignancy. Follow-up should be tailored according to the tumor site and might be limited to 3-5 years. What is Known: • Sialoblastoma is a rare congenital malignant tumor with an unpredictable clinical outcome. What is New: • Sialoblastoma of submandibular origin seems to have a less aggressive behavior in comparison with other sites. • Fine-needle aspiration and markers to assess proliferation index (i.e., suggestive of potential more aggressive course/malignancy) should be strongly considered in the diagnostic work-up. • Radical surgery as first-line therapy and a 3-5-year follow-up are acceptable for tumors with a low malignancy.

Congenital minor salivary gland sialoblastoma: a case report and review of the literature.

Sialoblastoma is the most common epithelial tumor of the salivary gland. We report a case of congenital sialoblastoma arising in a minor salivary gland of the buccal mucosa of a male infant. After radiologic evaluation, an incisional biopsy was performed and then the mass was excised en bloc. Histologic features were both favorable and unfavorable. However, there was no recurrence for 5 months. In spite of a reported histologic grading system, the clinical course of isolated sialoblastoma is considered unpredictable. More published case reports of this rare tumor may enable histologic and clinical correlation in order to accurately predict prognosis.

Unilateral congenital facial nerve paralysis secondary to a benign epithelioid peripheral nerve sheath tumor.

OBJECTIVE: A benign epithelioid peripheral nerve sheath tumor is described in the setting of congenital facial nerve (FN) paralysis. This is the first reported case in the English literature. PATIENT: A 10-month-old girl with unilateral congenital FN paralysis. INTERVENTIONS: Auditory brainstem evoked potential study, gadolinium-enhanced magnetic resonance imaging, temporal bone computed tomography, and transmastoid FN decompression with tumor resection. MAIN OUTCOME MEASURES: Follow-up for tumor recurrence and postoperative FN function. RESULTS: The child underwent a transmastoid FN exploration with resection of a 0.6-cm spherical tumor analyzed to be a benign epithelioid peripheral nerve sheath tumor. There is no evidence of recurrence, and FN function was unchanged at 1 year postoperatively. CONCLUSION: Benign epithelioid peripheral nerve sheath tumor can cause congenital facial nerve palsy.

Sialoblastoma: a clinicopathologic and immunohistochemical study of 7 cases.

Sialoblastoma is a rare congenital or perinatal salivary tumor that varies in histologic features and biologic potential. Seven cases from the files of the Armed Forces Institute of Pathology are presented. These tumors occurred in 4 males and 3 females with ages ranging from prenatal to 6 months at the time of discovery. Five lesions originated from the parotid gland; 2 lesions were from the submandibular gland. All lesions presented as nodular to multinodular swellings and ranged in size from 2.0 to 7.0 cm. The principal sign or symptom was rapid growth. Two histologic patterns with differing behavior predominated: (1) a favorable pattern had semiencapsulation of cytologically benign basaloid tumor cells with intervening stroma; and (2) an unfavorable histology of anaplastic basaloid tumor cells, minimal stroma, and broad pushing to infiltrative periphery. Four and three tumors had favorable and unfavorable growth patterns, respectively. One unfavorable lesion had vascular invasion, and another demonstrated perineural invasion. All 3 tumors with unfavorable histology recurred. Tumor cells in 3 cases were immunohistochemically reactive for keratin, S-100, smooth muscle actin, and calponin to varying degrees. All 3 tumors were reactive for p63. alpha-Fetoprotein was expressed in 2 unfavorable tumors. Ki67 was expressed at 3% in a favorable tumor and 40% and 80% in the 2 unfavorable lesions. Treatment involved surgical excision. One patient received adjuvant chemotherapy. Two sialoblastomas resulted in recurrences within a year and another developed a recurrence after 4 years. One sialoblastoma developed lung metastasis within 1 month of the original biopsy. Although a clinical correlation is suggested by a favorable/unfavorable histologic grading system the biologic behavior is nonetheless considered unpredictable.

Sialoblastoma: a rare submandibular gland neoplasm.

A sialoblastoma is a rare congenital epithelial tumor that arises in a major salivary gland. To our knowledge, only 24 cases of sialoblastoma have been previously reported in the English-language literature. We report a new case, that of a 15-month-old boy who presented with a submandibular mass. Surgical excision of the mass was undertaken. Intraoperatively, the mass appeared to be adjacent to the submandibular gland, but it had not invaded it. The mass was excised, and the submandibular gland was left in place. Pathology identified the tumor as a sialoblastoma. However, pathology also revealed that residual tumor was present at the surgical margin. The patient was returned to the operating room for excision of the left submandibular gland and the level I lymph nodes. Following revision surgery, the surgical margins were negative. The patient remained disease-free at the 1-year follow-up. Despite the need for revision surgery, this case provides support for the idea that surgery alone is sufficient for curative treatment.

Sialoblastoma: a case report and review of the literature on congenital epithelial tumors of salivary gland origin.

The histologic, immunohistochemical, and ultrastructural features of a congenital epithelial tumor of the parotid were studied. The tumor was characterized by solid nests of epithelial cells intermingled with proliferating ductal structures lined by a double layer of cells. Immunoperoxidase staining for cytokeratin, vimentin, actin, and S-100 protein showed the presence of cytokeratin in the ductal cells as well as the presence of vimentin, actin, and S-100 protein in the outermost layer of the ducts. The solid nests were focally reactive to S-100 and vimentin. Ultrastructural examination revealed myoepithelial cells with replication of basement membrane material. The tumor recurred 17 months after excision without lymph node involvement or metastasis. The term "sialoblastoma" is favored. Review of the literature on congenital, epithelial salivary gland tumors showed that a few cases recurred locally and only one case had regional lymph node involvement. No distant metastasis has been reported.