Plasmacytoid myoepithelioma of minor salivary glands: report of case with emphasis in the immunohistochemical findings

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.

Mucinous myoepithelioma: A report of a new variant

Myoepitheliomas account for approximately 1.5% of all salivary gland tumors and arise most frequently from the parotid gland. Recently, a new myoepithelioma variant, called mucinous myoepithelioma, has attracted widespread attention. These tumors are recognized as a unique subtype of myoepithelioma, characterized by the presence of abundant mucin. We herein report the findings of an 86-year-old Japanese woman who presented with a hard mass of the right parotid gland behind her right ear which was gradually increasing in size. The patient had undergone a fine-needle aspiration biopsy 4 years earlier, and a cytological evaluation of a biopsy specimen had shown features of pleomorphic adenoma. A resection was thus performed and the tissue was found to be an encapsulated, soft and solid mass, and the cut surface was observed to be a capsulated and well-defined tumor lesion with myxoid-looking foci of gray-white coloration. Microscopic examination revealed that this lesion was composed of a proliferation of bland-looking epithelial and myoepithelial cells, arranged in a solid or reticular growth fashion in an abundant myxomatous or hyalinized stroma. These neoplastic epithelial cells had centrally located small nuclei with fine chromatin and abundant clear to eosinophilic cytoplasm, often containing mucin in a uniform pattern. Immunohistochemical staining demonstrated the tumor cells to be positive for AE1/AE3, S-100 and mucicarmine. Our findings suggest this case to be one myoepithelioma variant of mucinous myoepithelioma, and more experience related to this myoepithelioma variant is necessary to better understand its biological behavior and make an accurate diagnosis for a proper treatment.

Psammoma Bodies in a Large Myoepithelioma

Myoepithelioma is a rare benign tumor of the salivary glands, in which the vast majority of neoplastic cells are myoepithelial. A rare microscopic finding in salivary gland tumors, including myoepitheliomas, is the presence of psammoma bodies (PBs), whose etiology and role in the tumors are uncertain. The objective of this study is to describe the unusual histopathologic findings, such as psammomas, of a large myopephelioma on the palate and the prosthetic restorative treatment performed after resection of the tumor. A 52-year-old woman was referred for evaluation of a tumor-like lesion, of smooth surface and normal mucosal color, measuring approximately 5 cm, on the left side hard palate, which had been identified 4 years earlier. The diagnostic hypothesis was a pleomorphic adenoma (PA), and an incisional biopsy was performed. After histopathologic analysis, a PA was suggested, and surgical resection of the tumor was performed. The histopathologic findings were compatible with myoepithelioma showing numerous calcified basophilic structures compatible with PB. Sixteen months after resection of the tumor, a removable maxillary obturator prosthesis was made because of the communication into oral and nasal cavity due from the surgical procedure. The treatment of choice for myoepithelioma is surgical excision with a nonlesional area margin. In the present report, the authors achieve good postoperative results without recurrences. After installation of the prosthesis, the patient had an excellent adaptation and acceptance, thus restoring her function and psychologic condition.

Plasmacytoid cells in salivary pleomorphic adenoma: an alternative interpretation of their immunohistochemical characteristics highlights function and capability for epithelial-mesenchymal transition

OBJECTIVES

Plasmacytoid cells (PLCs) in salivary pleomorphic adenoma (SPA) are regarded as modified neoplastic myoepithelia and define plasmacytoid myoepithelioma (pMYO). However, histochemically, immunohistochemically and ultrastructurally, PLCs fail to demonstrate frank myogenous properties. Epithelial-mesenchymal transition (EMT) may explain the phenotypes in SPA. Our aim was to evaluate (1) PLCs with accepted or purported myoepithelial and EMT-related markers; and (2) pMYOs for PLAG1 aberrations by using fluorescence in situ hybridization.

STUDY DESIGN

Eight SPAs with or without PLC-predominance and 3 pMYOs were immunohistochemically studied.

RESULTS

PLCs in SPA and pMYO exhibited strong, scattered to diffuse positivity for K7, rare K14 positivity and were mostly negative for α-smooth muscle actin, h-caldesmon, and p63/p40. S100 staining was strong and diffuse, whereas calponin was variable. DOG1 was negative. PLCs in pMYO and PLC-rich SPA exhibited selective or diffuse WT1 and D2-40 immunoreactivity. EMT markers SNAIL/SLUG exhibited strong and variable immunoreactivity in PLCs in contrast to weak or absent E-cadherin expression. SOX10 was diffusely and strongly positive. PLAG1 rearrangement was present in 1 pMYO.

CONCLUSIONS

PLCs mostly fail to express myoepithelial markers; PLCs are neoplastic cells adapting to microenvironmental changes and capable of EMT; and tumors composed solely of PLCs are apparently SPAs depleted of a ductal component.

Characterisation of DOG-1 Expression in Salivary Gland Tumours and Comparison with Myoepithelial Markers

DOG1 is an established diagnostic marker for gastrointestinal stromal tumours (GIST), but has been reported in salivary gland tumours (SGT) as an acinar and intercalated duct marker. However, its specificity and distribution is not well established. The aim of this study was to evaluate the diagnostic utility of DOG-1 expression in SGT in addition to comparing it with myoepithelial markers. Normal salivary tissue and SGT (n = 184) were examined for expression of DOG1 and a range of myoepithelial markers. SGT included: acinic cell carcinoma (ACC, n = 15), secretory carcinoma (SC, n = 9), pleomorphic adenoma (PA, n = 49), carcinoma ex-PA (Ca ex-PA, n = 11), adenoid cystic carcinoma (AdCC, n = 20), polymorphous adenocarcinoma (PAC, n = 6), myoepithelioma (n = 6), myoepithelial carcinoma (MC, n = 2), basal cell adenoma (BCA, n = 14), canalicular adenoma (CA, n = 19), mucoepidermoid carcinoma (MEC, n = 11), oncocytoma (n = 2), adenocarcinoma NOS (AdNOS, n = 4), basal cell adenocarcinoma (BCAC, n = 2), salivary duct carcinoma (SDC, n = 3) and papillary cystadenocarcinoma (PCAC, n = 1). Normal acini and ACC (14/15) showed strong luminal DOG1 staining; SC were largely negative with only focal expression in 3/9 cases. Luminal staining was seen in PA (14/49), PAC (4/6), Ca ex-PA (4/11) and AdCC (6/20). 8/11 MEC showed luminal and/or mucous cell staining. No staining was seen in myoepithelioma, MC, CA, adNOS and BCAC. BCA showed strong staining of myoepithelial cells in some cases (5/14). Variable myoepithelial DOG1 staining was seen in PA, Ca ex PA, BCA, SDC and PCAC which was not as consistent as myoepithelial markers such as calponin, p63 and αSMA. Absence of DOG1 can differentiate ACC from SC, but staining is variable in PA, PLGA and Ca ex-PA. Myoepithelial staining in some tumours but not in normal gland suggests a wider distribution in SGT than originally envisaged.

Plasmacytoid Myoepithelioma of the Hard Palate: Case Report

Background

Myoepitheliomas are uncommon salivary gland neoplasms consisting entirely or predominantly of cells with myoepithelial phenotype. They commonly involve the parotid gland and the minor salivary glands of the palate.

Aim

A case of plasmacytoid myoepithelioma of the hard palate is described.

Case description and results

A 55-year-old woman presented to her oral surgeon with a tumor on the hard palate. Microscopic examination showed a well-circumscribed but non-encapsulated tumor, consisting mostly of plasmacytoid cells in a loose fibrovascular stroma. Neoplastic myoepithelial cells showed immunoreactivity for S-100 protein, CK AE1/AE3 (Figure 5b), GFAP, calponin, and CD138/Syndecan-1. Total excision of the tumor under local anesthesia was performed and no recurrence was noted 14 months after treatment.

Conclusions

Since plasmacytoid myoepithelioma is uncommon, minor salivary glands, its immunohistochemical features, management and prognosis should be further investigated.

Unusual neoplasm on the hard palate of a child: a case report

Background

Myoepitheliomas account for less than 1% of salivary gland tumors. They mostly affect the parotid glands of adults during the third to fifth decades.

Case presentation

A 10-year-old Indian boy reported a small swelling in the roof of his mouth of 10 days’ duration. History revealed that the lesion was painless and not associated with bleeding or pus discharge. On examination, a purplish well-circumscribed growth was noted on his posterior hard palate. Magnetic resonance imaging was suggestive of a well-encapsulated hemangioma. An excisional biopsy was performed and histopathology along with immunohistochemistry analysis showed that the lesion was a spindle cell variant of benign myoepithelioma.

Conclusion

Palatal myoepitheliomas are rare and their occurrence in young individuals is rarer.

Epithelioid osteoblastoma of maxilla: A rare and aggressive variant of a benign neoplasm at an uncommon site

Osteoblastoma (OB) is an uncommon benign bone-forming tumor accounting for <1% of all bone neoplasms. Unlike conventional OB, its small subset variant “Epithelioid osteoblastoma (EO)” is characterized by its propensity for local invasion and recurrent behavior. This rare variant of an uncommon tumor when occurs in an atypical site can lead to diagnostic problems more so due to ambiguous clinico-radiologic presentation. This was what faced in the present case of 18-year-old female with a swelling in upper jaw. OB is usually more common in males and involves primarily the posterior element of the spine and the sacrum (40–55%). Less frequently, long bones of limbs are involved. Clinical, radiological and histopathological correlation in this case guided us to reach at right diagnosis of EO which helped the patient in getting correct treatment which involves surgical excision over conventional curettage. The purpose behind this case presentation is to improve the awareness about this recurrent tumor variant which has many close differentials including well-differentiated osteoblastic osteosarcoma.

Plasmacytoid-Type Cellular Differentiation in Polymorphous Low-Grade Adenocarcinoma

INTRODUCTION

Polymorphous low-grade adenocarcinoma (PLGA) occurs more frequently in minor salivary glands. The diagnosis of PLGA, in general, is not difficult but in occasional tumors showing limited invasion or in small biopsy specimens, PLGA may be confused with cellular pleomorphic adenoma (PA). Plasmacytoid cells, a usual component of PAs, have been considered helpful for correct tumor identification.

OBJECTIVE

The aim of this study was to verify the frequency (if any) of plasmacytoid-type cellular differentiation (PD) in PLGA.

MATERIALS AND METHODS

Thirty-two cases of PLGA were reviewed. PD was recognized in 2 cases (6.25%), in which immunohistochemical expression of AE1/AE3, CK7, CK14, vimentin, α-SMA, p63, S-100, calponin, GFAP, and Ki-67 was evaluated.

RESULTS

The 2 cases presented conventional areas of PLGA and variable quantities of cells with PD forming aggregates in the stroma and lining ductal structures. Cells with PD showed positivity for AE1/AE3, CK7, S-100, and vimentin and were negative for CK14, calponin, and GFAP in both cases. In case 1, cells with PD did not present α-SMA and p63 positivity whereas in case 2 they were positive, but for α-SMA such reactivity was restricted to cells forming solid aggregates.

CONCLUSION

Although PD in PLGA is rare, it is necessary to be aware of this possibility, particularly in small incisional biopsies and in PLGA with limited invasion, to avoid confusion with cellular PA.

Innervation of submandibular and sublingual glands in elderly donated cadavers: a preliminary histological study of differences in nerve morphology between mucous and serous acini

We examined morphological differences between the sublingual and submandibular glands with special reference to their innervation. The sublingual gland contained abundant periodic acid Schiff-positive mucous acini: some lobules were composed of purely mucous acini, while others were purely serous or mixed. However, in the submandibular gland, the area of mucous acini was very limited. Notably, in the sublingual gland, immunohistochemistry for neuron-specific enolase demonstrated that the serous acini carried a higher density of nerve elements than the mucous acini. However, no such difference was evident in the submandibular gland, possibly due to the small areas of the mucous acini. In both types of gland, neuronal nitric oxide synthase-positive parasympathetic nerves as well as tyrosine hydroxylase-positive sympathetic nerves were observed in the interlobular tissue, but we were unable to trace these thin fibers to the acini. Myoepithelial cells expressed smooth muscle actin, but were negative for S100B protein, glial fibrillary acidic protein and neuron-specific enolase. However, antibody against S100A stained some of the myoepithelial cells and ductal cells in the sublingual gland. Cells positive for peripheral myelin protein 22 were seen in some of the ductal cells in the submandibular gland, but not in the sublingual gland. Therefore, with regard to the neurogenic features of the gland cells, S100B reactivity might disappear first in postnatal life, whereas S100A reactivity is likely to remain as aging progresses. The sublingual gland in elderly individuals seems to provide a good model for comparison of the nerve supply between mucous and serous acini.

Heterogeneity of glandular cells in the human salivary glands: an immunohistochemical study using elderly adult and fetal specimens

Using immunohistochemical staining for alpha-smooth muscle actin (α-SMA), glial fibrillary acidic protein (GFAP), S100 protein (S100), p63, cytokeratin 14 (CK14), and cytokeratin 19 (CK19), we studied acinar and myoepithelial cells of major and minor salivary glands obtained from 14 donated cadavers (78-92 years old) and 5 donated fetuses (aborted at 15-16 weeks of gestation). CK and p63 expression was investigated only in the adult specimens. SMA was detected in all adult glands as well as in fetal sublingual and pharyngeal glands. GFAP expression was seen in a limited number of cells in adult glands, but was highly expressed in fetal pharyngeal glands. S100-positive myoepithelial-like cells were present in adult minor glands as well as in fetal sublingual and pharyngeal glands. Expression of p63 was evident in the ducts of adult glands. CK14 immunoreactivity was observed in a limited number of glandular cells in adults, in contrast to consistent expression of CK19. In both adults and fetuses, a mosaic expression pattern was usually evident for each of the examined proteins. A difference in immunoreactivity for the nerve markers GFAP and S100 was observed between the major and minor glands. Thus, in the present histologic study, we distinguished between the specific gland types on the basis of their immunohistochemical staining. A mosaic expression pattern suggested that the immunoreactivity against nerve protein markers in myoepithelial cells could not be due to the persistence of neural crest remnants or the physiological status of the gland, such as age-related degeneration.