Light microscopic, ultrastructural and immunocytochemical spectrum of malignant lacrimal and salivary gland tumors, including malignant mixed tumors

Rare Diseases of the Orbit

This article provides an overview of rare orbital diseases. Congenital malformations, inflammatory diseases, benign and malignant neoplasias are described. Although it represents a relatively small area of the body the orbit contains multiple different tissues. Therefore, a great variety of diseases can be found within the orbital space. That is the reason, why both the completeness and the level of detail in the description of particular diseases must be somewhat limited. Nevertheless, clinical manifestations, important aspects of diagnosis, treatment strategies, and, when specific data are available, the prognosis are described. The authors tried to highlight the most characteristic aspects of the different diseases to describe their relevant aspects in spite of the brevity of the subsections.

Myoepithelioma of the Lower Eyelid

A 59-year-old woman presented with a 4-year history of a progressively growing, subcutaneous, painless, left lower eyelid mass with associated swelling and discomfort. Excisional biopsy established the diagnosis of a myoepithelioma, a tumor which, to the authors' knowledge, has not been previously reported in the lower eyelid.

Diagnostic pitfall: primary myoepithelial carcinoma of the lacrimal gland, case report and literature review

Background

In lacrimal gland, lymphomas and inflammatory lesions predominate. Primary epithelial tumours represent less than 30% of lacrimal gland lesions. Myoepithelial carcinoma of lacrimal gland is rare. To the best of our knowledge, only nine cases have been reported in the literature. This lesion presents diagnostic difficulties: non-specific clinical and radiological findings and histological polymorphism. This is well illustrated by the diagnostic pathology errors described in the literature.

We report a new case of lacrimal myoepithelial carcinoma with a review of others published cases to try to assess clinico-pathological features and outcome whenever possible of this rare tumour.

Case presentation

An 80-year-old Arabian female presented with a 2-month history of swelling over the right eyebrow, pain, proptosis of the right eye and diplopia. Computed tomography demonstrated an ill-defined, homogeneous, contrast-enhancing mass attached to the medial rectus. A biopsy was performed. Microscopic examination showed malignant spindle cells tumour, most consistently to sarcoma or sarcomatoid carcinoma. Immunohistochemical study was not possible because neoplastic material has been exhausted. Subsequently, total exenteration of the right orbit was performed. Immunohistochemical study revealed diffuse positive staining for pancytokeratin AE1/AE3, epithelial membrane antigen (EMA) and smooth muscle actin (SMA) and focal positivity for S100 protein. The lesion was immunonegative for desmin, h-cladesmon, CD34, Melan-A and HMB-45. The tumour was extending to the surgical margins. The patient was lost to follow-up until she developed local tumour progression 3 months after removal. The patient was again lost to follow-up and therefore did not receive any other treatment in our hospital.

Conclusion

We present this rare tumour with an unusual location. The use of a complete immunohistochemical panel with epithelial and myoepithelial markers positivity helped us for classification of this poorly differentiated tumour.

Lacrimal myoepithelial carcinoma ex recurrent pleomorphic adenoma: A clinicopathological report and review of the literature

Myoepithelial carcinoma is an uncommon malignant tumor of the lacrimal gland, composed of neoplastic myoepithelial cells with an infiltrative growth. The present study describes a unique case of progressive proptosis and blindness of the right eye in a 68-year-old woman following total tumor removal for lacrimal pleomorphic adenoma. Clinical study, surgical exploration, and pathology revealed lacrimal myoepithelial carcinoma ex recurrent pleomorphic adenoma, T2N0M0. In addition, 18 cases of lacrimal myoepithelial tumor that have been previously described in the literature are reviewed. The application of clinical, radiological, histopathologic, and immunohistochemical investigations may help to reach the definite diagnosis. Criteria for malignancy of lacrimal myoepithelial tumor should be the same as salivary myoepithelial tumor diagnosis, until long-term outcome data for a larger number of patients with lacrimal myoepithelial carcinoma become available.

De novo myoepithelial carcinoma with multiple metastases arising from a submandibular salivary gland: A case report

Salivary gland carcinomas are rare tumors, representing ~0.5% of all malignancies. Myoepithelioma is also uncommon, representing ~1% of all salivary gland tumors. Myoepithelial carcinoma (MC) is even rarer, representing 0.2 to 0.6% of all salivary gland tumors. We herein report a case of MC with multiple metastases arising from a submandibular gland in a 71-year-old male patient and present the associated imaging findings. The patient was considered to have a de novo type of myoepithelial carcinoma, which is reportedly associated with higher malignancy than the transformation type of the disease (i.e., a malignant change from pleomorphic adenoma or myoepithelioma). This was reflected in the multiple lung and bone metastases sites and strong positivity for p53 and Ki-67.

Malignant Myoepithelioma of Salivary Glands: Clinocopathologic and Immunophenotypic Features

Malignant myoepithelioma is a rare salivary gland carcinoma that might be confused with other neoplastic lesions, including carcinoma and sarcoma. A review of 10 previ ously reported acceptable cases and 2 new ones shows that the tumor affects older individuals with a mean age of 60 years. The parotid gland was the site of tumor in eight cases and the minor salivary glands of the mouth in four. Microscopically, 9 of the 12 tumors were composed either partly or predominantly of spindle-shaped cells. Plasmacytoid cells were the second most common cell type, and round or epithelioid cells were the least common type. Immunohistochemical evidence of myoepithelial differentiation in 10 evaluated cases included positive staining with antibodies against cytokeratin, muscle specific actin, S 100 protein, and vimentin. Ultrastructural features of a myoepithelial phenotype in nine studied cases were cytoplasmic microfilaments with focal densities, desmosomal cell junctions, basal lamina, and hemidesmosomal junctional plaques. Because of a limited number of reported cases and a paucity of follow-up data, it is not possible at present to accurately predict the clinical course of malignant myoepithelioma of salivary glands. However, it appears that local recurrence is an important cause of treatment failure. Metastasis is infrequent. Int J Surg Pathol 2(2):133-140, 1994

Tumors of the lacrimal gland

Tumors of the lacrimal gland comprise a wide spectrum, of which the most common demonstrate epithelial and lymphoid differentiation. The diagnosis of lacrimal gland tumors depends primarily on histological evaluation, as do the choice of treatment and prognosis. For some lacrimal gland neoplasms, such as adenoid cystic carcinoma, the outlook is grave. Optimal treatment for several lacrimal gland tumors is also a matter of controversy. However, recent progress has been made in the molecular and genetic understanding of tumorigenesis for such lesions. This article presents an overview of the histopathology of lacrimal gland tumors, together with their epidemiological features, clinical characteristics, and treatment strategies.

Myoepithelioma of the Orbital Apex and Middle Cranial Fossa: Case Report and Review of the Literature

Myoepitheliomas are rare tumours that originate from glandular tissues such as the parotid or salivary glands, and less commonly from soft tissues of the head, neck, and other parts of the body. Intraorbital myoepitheliomas generally arise from the lacrimal gland. Intracranial myoepitheliomas are rare. We report a myoepithelioma of the orbital apex that did not originate from the lacrimal gland. It extended to the middle cranial fossa from the orbital apex and involved the dura and adjacent bone. A diagnostic biopsy via a lateral orbitotomy preceded resection. We review the natural course and histopathology of myoepithelial neoplasms, the surgical nuances of approaching an orbital apex tumour with maximal functional preservation, and the optimal management practices of these rare lesions.

[Myoepithelial carcinoma of the lacrimal gland]

INTRODUCTION

Myoepithelial carcinomas are unusual tumors most often located in salivary glands. It is very rarely located in lacrimal glands; only 5 cases have been reported. We report a sixth case.

OBSERVATION

An 88-year-old male patient presented with diplopia, painless right sided exophthalmia, as well as eyeball deviation due to a tumor located at upper external quadrant of the orbit. A biopsy initially suggested a sarcoma. The pathological analysis of the biopsy allowed diagnosing a myoepithelial carcinoma of the lacrimal gland. Despite the monoblock resection of the tumor, a recurrence was observed 3 months after removal. The patient died 8 months after the initial surgery.

DISCUSSION

This case illustrates the clinical and pathological characteristics of a myoepithelial carcinoma. This tumor has a high grade of malignancy, and is very rarely described in lacrimal glands. The morphological diagnosis of this tumor is difficult with a problematic differential diagnosis with fusiform cells sarcomas (leiomyosarcoma, undifferentiated sarcoma), and epithelial-myoepithelial carcinoma.

Epithelial tumours of the lacrimal gland: a clinical, histopathological, surgical and oncological survey

Epithelial tumours of the lacrimal gland represent a large spectrum of lesions with similarities in clinical signs and symptoms but with different biological behaviour and prognosis. They are rare, but with aggressive malignant potential. Tumours of the lacrimal gland may present with swelling of the lacrimal gland, displacement of the eyeball, reduced eye motility and diplopia. Pain and symptoms of short duration before the first ophthalmic consultation are characteristic of malignant tumours. The histological diagnosis determines the subsequent treatment regimen and provides important clues regarding the prognosis. The purpose of this paper is to describe the various primary epithelial tumours of the lacrimal gland. In the first part of the review, the frequency, demographics, clinical presentation and diagnostic features are described. In the second part, primarily tumour-specific histological characteristics are given. Finally, treatment modalities including surgical procedures and medical oncology as well as prognosis are discussed.

Undifferentiated Carcinoma of the Salivary Gland in a Chinchilla (Chinchilla Lanigera)

A 12-year-old chinchilla ( Chinchilla lanigera) developed a slow-growing, soft, fluctuating, nonpainful mass on the ventral neck with focally extensive alopecia over a period of approximately 8 months. On postmortem examination, an extensive, multilobulated, cystic, neoplastic mass extended subcutaneously over the ventral and lateral neck with metastatic spread to submandibular lymph nodes, spleen, liver, and lungs. Neoplastic cells were strongly positive for vimentin and pan-cytokeratin but were negative for alpha–smooth muscle actin, S100, and myosin; no intracytoplasmic myofibrils were detected on phosphotungstic acid hematoxylin staining. Histologic and immunohistochemical examination of the mass led to a diagnosis of undifferentiated carcinoma of the salivary gland and contributes to the paucity of knowledge concerning neoplasia in chinchillas.

Primary myoepithelioma of the orbit in an infant

Myoepitheliomas are rare tumors with various growth patterns and cellular variants. Primary myoepithelioma is rare in the orbit, with most previously reported cases involving the lacrimal gland region of adult patients. The authors report the case of a primary orbital soft tissue myoepithelioma in a 3-month-old boy. Diagnostic criteria and management considerations of this unusual tumor presenting in a young child are discussed.

Benign myoepithelioma of the lacrimal gland: report of a case

Myoepithelioma of the lacrimal gland is an extremely rare monomorphic adenoma, with only six previously reported cases in the literature. We herein report the radiological, clinical and histopathological evaluation of a 46-year-old patient with a history of right eye proptosis and progressive diplopia. A mass in the right lacrimal fossa was detected at MRI and turned out to be benign myoepithelioma of the lacrimal gland at the histopathological examination. The patient underwent excision of the mass by means of a coronal bitemporal approach and lateral orbitotomy. The lesion was entirely removed "en-bloc" with the lacrimal gland. MRI did not show any evidence of recurrent disease 12 months after surgery. The patient was clinically free of disease after 22 months. Surgery is the treatment of choice for this kind of lesion. The coronal bi-temporal approach herein reported offered good exposure of the entire lesion and a satisfactory aesthetic result. Periodic postoperative radiological evaluations with MRI are mandatory.

Defining the role of myoepithelium in salivary gland neoplasia

Neoplastic myoepithelium is considered to be the key cellular participant in morphogenetic processes responsible for the variable histologic appearances of many salivary gland tumors. Nevertheless, controversy still exists concerning its participation in some types of salivary gland neoplasms. This has been largely due to the difficulty in fully characterizing the wide spectrum of morphologic and immunophenotypic expressions of neoplastic myoepithelium compared with the normal counterpart. However, in recent years, our understanding regarding the phenotypic, immunophenotypic, ultrastructural, and biochemical properties of myoepithelium has advanced. Here we discuss the role of neoplastic myoepithelium in the scope of salivary gland neoplasia and present this information from a practical diagnostic standpoint.

Myoepithelial carcinoma of the salivary glands: a clinicopathologic study of 25 patients

Salivary gland carcinomas displaying exclusively myoepithelial differentiation (myoepithelial carcinoma) are considered rare. Their histopathologic features, immunohistochemical profile, and clinical behavior are not well characterized. The authors reviewed the clinicopathologic features of 25 salivary gland tumors fulfilling two fundamental histologic criteria: unequivocally malignant and exclusively myoepithelial. For most of these, the original diagnosis was malignant mixed tumor. Thirteen men and 12 women aged 24 to 77 years (mean age, 55 yrs) participated in the study, and most presented with a painless mass. The parotid gland was the most common site (n = 15). Tumors ranged from 2.1 to 5.5 cm, arising either in association with a benign mixed tumor (n = 15) or de novo (n = 10). Histologically, all the tumors displayed infiltrative growth and most had a characteristic multinodular architecture with a cellular periphery and central necrotic/myxoid zones. Epithelioid, hyaline, spindle, clear, or mixed cell types were noted with accompanying myxoid and/or hyalinized extracellular matrix. Ten tumors were high grade cytologically and 15 were low grade. The mitotic rate ranged from three to 51 mitoses per 10 high-power fields. Necrosis was present in 15 tumors and perineural and vascular invasion were identified in 11 and four neoplasms respectively. Immunoreactivities included CAM5.2 (89%), AE1:AE3 (100%), 34betaE12 (92%), cytokeratin 7 (21%), cytokeratin 14 (53%), vimentin (100%), S-100 protein (100%), smooth muscle actin (50%), calponin (75%), muscle-specific actin (31%), glial fibrillary acidic protein (31%), carcinoembryonic antigen (0%), and epithelial membrane antigen (21%). Ultrastructural examination of three tumors showed myoepithelial features. Ten patients developed recurrences, mostly multiple. Follow up of 17 patients showed that eight patients (47%) developed metastases (six high grade, two low grade) and five patients (29%) died of disease (four high grade, one low grade) after a mean of 32 months. Two patients were alive with disease (19 and 49 mos). Ten patients (59%) were without any evidence of disease after a mean of 42.2 months. Myoepithelial carcinomas exhibit a wide spectrum of cytomorphologic features and diverse clinical outcomes. As a result of their morphologic heterogeneity, they can be confused easily with many tumors. Myoepithelial carcinomas have been underrecognized in the past, primarily by being lumped under a broader category of "malignant mixed tumor." Awareness of their unique cytoarchitectural patterns and immunohistochemical profile is crucial for accurate identification.

Myoepithelioma of the lacrimal gland: report of a case with potentially malignant transformation

Myoepithelioma of the lacrimal gland is extremely rare and only four cases, one of which was malignant, have been reported in detail. The present report describes a case of lacrimal gland myoepithelioma in a Japanese male with histological features suggestive of potentially malignant transformation. The excised tumor consisted of two components, a central nodular component and a peripheral component surrounding the former. These components were separated by a fibrous tissue. Microscopically, both components were comprised almost entirely of spindle-shaped cells, but with some epithelioid cells containing glycogen granules. Extracellular spaces in the peripheral component were filled with eosinophilic materials with the occasional crystalloid structures, which were immunoreactive for collagen type I. Neoplastic cells were immunoreactive focally for vimentin and S-100, but negative for cytokeratins, epithelial membrane antigen, muscle actin, smooth muscle actin, desmin, myosin, and glial fibrillary acidic protein. The neoplastic cells in the central component showed nuclear pleomorphism and atypia with a higher frequency of mitotic figures, and higher labelings of proliferation markers than those in the peripheral component. Neither invasion, necrosis, nor hemorrhage was observed in the tumor. From these findings we proposed a diagnosis of potentially malignant myoepithelioma.

Malignant myoepithelioma of the salivary glands: clinicopathological and immunohistochemical features

Malignant myoepitheliomas (myoepithelial carcinomas) are uncommon, and we know of only 29 reported cases. We present a new case together with its clinical, histological, and immunohistochemical features. The tumour was located in the inferior vestibular sulcus of a 64-year-old woman. She was treated by wide local resection. Malignant myoepitheliomas are distinguished from benign myoepithelial neoplasms by their infiltrating and destructive growth. The tumour cells may be spindle-shaped or more rounded (plasmacytoid cells) and contain cellular pleomorphism and mitotic activity. The clinical and biological behaviour of this tumour is not yet known and there is little information about treatment and prognosis.

Salivary gland malignant myoepithelioma: a clinicopathologic and immunohistochemical study of ten cases

BACKGROUND

Malignant myoepithelioma (MME) of the salivary gland, also known as myoepithelial carcinoma, is rare and its biologic behavior has not been clarified fully.

METHODS

Ten cases of MME were analyzed for their clinicopathologic features and immunohistochemical characteristics, focusing on prognostic factors and tumor differentiation. In addition, six cases of benign myoepithelioma (BME) also were examined for comparison.

RESULTS

The ten patients with MME (3 men and 7 women) ranged in age from 48-81 years (mean, 61.9 years). Seven cases of MME arose in the parotid salivary gland, two in the submandibular salivary gland, and one in minor salivary glands of the soft palate. In the current series, the incidence of MME was 0.45% among 1945 cases of major salivary gland tumors. Seven cases of MME developed from a benign preexisting tumor (six in pleomorphic adenoma and one in BME). Four of nine patients with MME died of the disease and two patients developed a recurrence. It was shown that MMEs were comprised of one cell type or a combination of two cell populations; these included, in order of incidence, epithelioid, spindle, and plasmacytoid cells. Patients with MME with marked cellular pleomorphism and perineural invasion had a poor prognosis. Immunohistochemically, putative myoepithelial markers such as muscle actins, cytokeratin 14, vimentin, and calponin, and S-100 protein were expressed highly in MME. High and low molecular weight cytokeratins and epithelial membrane antigen also frequently were positive in MME. p53 expression was observed in five MME cases, four of which either recurred or were fatal. Cellular proliferative activity assessed by mitotic count and the Ki-67 labeling index was significantly higher in MME cases than in BME cases. In limited cases, such cellular proliferative activity was shown to have prognostic value. Ultrastructurally, the tumor cells displayed certain myoepithelial characteristics.

CONCLUSIONS

MME is a rare salivary gland tumor showing clinicopathologic diversity and presenting with various stages of myoepithelial differentiation. Histologic aggressiveness, marked cellular pleomorphism, p53 expression, and high cell proliferative activity were found to be correlated with a poor clinical outcome.

Myoepithelial carcinoma arising in a benign myoepithelioma: immunohistochemical, ultrastructural, and flow-cytometrical study

A case of myoepithelial carcinoma arising in a benign myoepithelioma of the minor salivary gland in a 71-year-old patient is reported. The tumor presented initially on the palate and had been diagnosed as "benign lesion" 40 years before. It recurred 22, 36, and 40 years after initial presentation, and a similar histopathological diagnosis was rendered. One year after the last recurrence, the tumor recurred showing typical changes of malignant transformation, and the diagnosis was malignant myoepithelioma. The light microscopy and ultrastructural features of the initial tumor were typical of plasmocytoid myoepithelioma. There were abundant round cells and rare spindle cells with uniform dispersed filaments, sometimes arranged in parallel streams without evidence of dense bodies. These cells showed micropinocytotic vesicles along the cell membrane with poorly developed intercellular junctions and were surrounded by a basal membrane. The malignant counterpart showed fewer plasmocytoid cells and a rather epithelial pattern with marked nuclear pleomorphism and formation of small, or rarely large, glandular lumina. The immunohistochemical features were similar for the benign and malignant tumors, with positivity for S-100 protein, vimentin, cytokeratins, and CAM 5.2, and were negative for GFAP, muscle-specific actin, CEA, and desmin. Flow cytometry showed a change in the DNA content profile. The benign myoepithelioma had a diploid DNA content with a low S-phase fraction of 3.9% and proliferative index of 9.1%, while the myoepithelial carcinoma had an evident aneuploid DNA stem line and an increased S-phase fraction of 8.3% with a proliferative index of 18.1%.

Pathology of the salivary glands: the contribution of electron microscopy

Electron microscopy has a limited role in the diagnosis of primary salivary gland tumors, although it can be helpful in metastatic lesions of possible salivary gland origin. The diversity of subtypes in salivary gland tumors, as well as the range of histomorphology within any one subtype, is unparalleled in any other human tumor. This and their relative infrequency causes diagnostic problems for pathologists. Ultrastructural techniques have been of major importance in determining the inter-relationship of these tumors for classification purposes, revealing the subtle variations in common cellular differentiation pathways, determining the organization of tumor cells, and displaying the importance of extracellular matrix materials in establishing diagnostic criteria for each of the many subtypes. Electron microscopy has also been valuable in non-neoplastic salivary gland disease and has an increasing role in experimental studies involving tissue from human and animal salivary parenchyma.

Immunohistochemistry with keratin, vimentin, desmin, and alpha-smooth muscle actin monoclonal antibodies in canine mammary gland: benign mammary tumours and duct ectasias

Duct ectasias (n = 2) and different types of benign canine mammary tumours (n = 19) were studied immunohistochemically with monoclonal antibodies (MoAbs) directed against various human keratin types (K), alpha-smooth muscle actin, vimentin, and desmin. In the duct ectasias and in most tumours the epithelial structures revealed an inner and outer cell layer. The inner cell layer was characterized by labelling with K 7, 8, 18, 19 and mostly also with K 4 and/or K 10 MoAbs. The outer cell layer was almost invariably labelled by K 14, K 14 and 17, and a-smooth muscle actin MoAbs. The labelling patterns of both duct ectasias and tumours corresponded largely to the patterns observed in normal mammary gland tissue, although a more distinct heterogeneity was seen. Tumours histomorphologically assumed to be of a myoepithelial origin did not show immunohistochemical features of myoepithelial cells. The myoepithelial nature of the vast majority of spindle-shaped cells present in the adenomas of the complex type and in the fibroadenomas of the benign mixed type could not be confirmed immunohistochemically. These cells, however, unequivocally expressed vimentin, suggesting proliferation of stromal cells in these tumours, which in the fibroadenomas of the benign mixed type may show metaplasia to bone or cartilage. In the duct ectasias and in some tumours, a fraction of elongated stromal cells, probably representing myofibroblasts, was labelled with the alpha-smooth muscle actin MoAb.

Malignant myoepithelioma of salivary glands: clinicopathological features of ten cases

Malignant myoepithelioma of the salivary gland is discussed in terms of its clinical behaviour, morphological features and the frequent pre-existence of a pleomorphic adenoma. The study comprised six female and four male patients aged 14-63 years (mean age 38.9 years). Two tumours presented as intraoral lesions and eight were located in the parotid gland. Tumour cells displayed a morphological spectrum ranging from round epithelioid cells to spindle-shaped and stellate cells. Most cells displayed reactivity for high molecular weight keratins and in four tumours there was strong immunoreactivity for smooth muscle actin. Malignant myoepithelioma seems to arise in two different clinical settings: either de novo or in a recurrent pleomorphic adenoma. De novo malignant myoepitheliomas arise in normal salivary gland, tend to be more aggressive and have a short clinical history. Recurrences may not develop or may occur as a single event within a short time interval, and metastases develop in the lungs. Malignant myoepitheliomas arising in recurrent pleomorphic adenomas have a long clinical history, are characterized by multiple recurrences and have to be distinguished from aggressive carcinomas arising in these adenomas. In contrast, the tumours described in the present series arising in pleomorphic adenomas showed local aggressiveness and metastases did not occur until decades after the first treatment. The general opinion that all malignant tumours that arise from pleomorphic adenomas are highly aggressive is not confirmed by the present study.