Malignant myoepithelioma arising from recurrent pleomorphic adenoma of the soft palate

Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review

PURPOSE

This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas.

METHODS

Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor.

RESULTS

Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up.

CONCLUSIONS

The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

Management of a giant pleomorphic adenoma of the soft palate: A case report

Key Clinical Message

Benign mixed salivary gland tumor is comprised of epithelial and myoepithelial cells and represents up to 80% of tumors of the parotid gland. It is relatively rare in the soft palate and in other minor salivary glands. Surgery is the standard care.

Abstract

Salivary gland tumors are relatively rare and morphologically diverse group of lesions. Pleomorphic adenoma (PA) is the most common salivary gland tumor, accounting for approximately 80% of all major and minor salivary gland tumors. PA usually affects the parotid gland. Huge PA occurring in soft palate is extremely rare. Patients with these tumors are usually between at the age of 40 and 60 years. The tumors exhibit pleomorphic nature microscopically that may pose diagnostic challenges to pathologists as may confuse PA histopathologically with other salivary gland tumors. Surgery is the standard treatment. The purpose of writing this case study is to describe unusual case of a giant PA of the soft palate found in a 44-year-old male successfully managed at our facility.

Myoepithelial Carcinoma Arising in a Plasmacytoid Myoepithelioma of the Parotid Gland Synchronized with Melanoma: A Case Report and Review of the Literature

Myoepithelial carcinoma, also known as malignant myoepithelioma, is considered an extremely rare (0.45-1%) malignant salivary gland neoplasm. Approximately 100 cases have been reported in the English-language literature on myoepithelial carcinoma. The majority of the myoepitheliomas described in the literature have been benign, and the malignant counterpart is considered rare (<1%). Such a tumor may appear de novo or rarely develop from a preexisting pleomorphic adenoma (<20%), and in exceedingly rare cases (<0.5%), it has arisen from a benign myoepithelioma (i.e., plasmacytoid myoepithelioma). To our knowledge, no case of myoepithelial carcinoma of the parotid gland arising in a plasmacytoid myoepithelioma synchronized with melanoma has been reported to date. The treatment of myoepithelial carcinoma has been mainly surgical, including wide excision with free margins, with or without nodal dissection. The roles of chemotherapy and radiotherapy have not yet been established. We report a case of myoepithelial carcinoma of the parotid gland arising in a plasmacytoid myoepithelioma synchronized with melanoma in a 40-year-old woman. In our case, a complete response was achieved with surgery followed by adjuvant chemotherapy based on carboplatin and paclitaxel concurrent with radiotherapy.

Low-grade malignant myoepithelioma arising in a pleomorphic adenoma: a rare case

Malignant myoepithelioma is a very rare salivary gland tumor that can arise de novo or within a pre-existing pleomorphic adenoma. We report a case of malignant myoepithelioma most probably arising in a pre-existing pleomorphic adenoma of the left parotid gland. The patient was a 60-year-old man who presented with a multinodular mass lesion over left side of the face and neck. He had undergone removal of a pleomorphic adenoma of the left parotid gland twice (8 and 22 years ago). Histological examination showed locally concentrated highly invasive myoepithelial cells with bland-looking morphology and no evidence of mitosis or necrosis. Immunohistochemistry confirmed the myoepithelial differentiation (S- 100+, SMA+) and a low Ki-67 labeling index (<5%).

Salivary Gland Myoepithelioma with Focal Capsular Invasion

Salivary gland tumors that display myoepithelial differentiation exclusively or predominantly are relatively uncommon, and the assessment of malignancy in a myoepithelial tumor can be difficult. We report a case of parotid gland myoepithelioma composed predominantly of spindle cells with focal capsular invasion. The patient was a 65-year-old woman who presented with a painless mass in the right preauricular region. Histologically, the tumor had a solid and multinodular growth pattern and was predominantly made up of spindle cells with a minor component of epithelioid cells with moderate cellular atypia. Focal regions of tumor cells infiltrated the capsule with tongue-like processes, hut tumor infiltration into the adjacent parotid tissue was absent. The tumor cells showed strong cytoplasmic immunoexpression of vimentin, pankeratin, S-100 protein, and smooth-muscle actin. Immunostains with glial fibrillary acidic protein, melanoma marker, epithelial membrane antigen, and carcinoembryonic antigen were negative. Expression of p53 was observed focally in the nuclei of the tumor cells. A final diagnosis of salivary gland myoepithelioma with focal capsular invasion was made, and the case was regarded as a myoepithelial tumor of uncertain malignant potential. In this report, we discuss the histologic criteria required to diagnose malignancy in salivary gland myoepithelial tumors.

Malignant myoepithelioma of the mastoid region - A case report

A 23-year-old male patient presented with a post auricular mass and an attico antral type of chronic suppurative otitis media. He underwent excision of the mass and canal wall down mastoidectomy. Histopathological diagnosis of malignant myoepithelioma was made.The patient refused treatment and later he died with systemic metastasis.This case is reported for the rarity of the site, young age of presentation and aggressive behaviour.