Dedifferentiated malignant myoepithelioma of the parotid gland

Dedifferentiated salivary gland tumor is a rare, recently recognized tumor type. A case of dedifferentiated malignant myoepithelioma in a 59-year-old man who presented with a painful mass in the left preauricular region is reported. Histologically, two distinct neoplastic cell populations were observed in the same tumor mass. The first population was composed of solid nests of polygonal eosinophilic or glycogen-rich clear cells showing neoplastic myoepithelial immunocytological features, such as positivity for cytokeratins, vimentin, S-100 protein (S-100), alpha-smooth muscle actin (SMA) and glial fibrillary acidic protein (GFAP). A multinodular growth pattern, necrosis and occasional mitotic figures suggested malignancy. This population was diagnosed as low-grade malignant myoepithelioma. The second population infiltrated diffusely into the parotid gland and facial nerves. It consisted of polygonal or short spindle cells with obvious pleomorphism and atypical mitoses. The tumor cells were positive for vimentin and cytokeratins, and showed an accumulation of p53 and cyclin D1. S-100 protein, SMA and GFAP were negative. This population was regarded as undifferentiated carcinoma. A final diagnosis of dedifferentiated malignant myoepithelioma was made. This seems to be the first published case of dedifferentiation in malignant myoepithelioma. Because any tumor type can undergo dedifferentiation with accumulation of additional genetic changes, complete sampling should be the standard approach to all salivary gland tumors in order to avoid missing a dedifferentiation component.     

Malignant myoepithelioma of minor salivary gland origin.

Myoepithelial cells are a significant component of most types of salivary gland tumors. A small but increasing number of case reports have also shown that true myoepithelioma (ME) forms a distinct clinicopathologic entity of salivary gland tumors with unique histologic features, however, the malignant type of ME is exceedingly rare. The present paper reports a case of malignant ME originating from the palatal minor salivary gland. The patient was a 70-year-old Japanese male with recurrent tumor of the palatal region. Pathologically, the tumor consisted of proliferating polygonal-shaped cells and plump spindle cells with cellular atypia and frequent mitoses, forming lumen-less lobuli or strands. Clear tumor cells were also found in part. The stroma was poorly developed without any myxoid or chondroid features. Immunohistochemical study showed positive stainings for S-100 protein, actin and vimentin in the tumor cells. Ultrastructurally, tumor cells had features of myoepithelial cells.     

Cytogenetic analysis of a primary salivary gland myoepithelioma.

Myoepithelioma, a rare benign salivary gland neoplasm, is a tumor composed entirely of myoepithelial cells. Unlike pleomorphic adenoma, these tumors lack any ductal epithelial differentiation, and manifest a minor stromal element. Previous cytogenetic and molecular genetic studies have mainly investigated pleomorphic adenomas and reported recurring specific chromosomal alterations at 8q12 and 12q13-q15 regions. The cell origin of these alterations, however, remains speculative. We report the cytogenetic analysis of a parotid myoepithelioma and discuss the putative origin for the cells with cytogenetic alterations. Our analysis shows 12q12 involved in a translocation with a previously unreported partner (1q), and nonrandom del(9)(q22.1q22.3) and del(13)(q12q22). Our results indicate that the myoepithelial cell is the source of those cells with chromosomal alterations, and that myoepithelioma shares 12q alterations reported in a subset of pleomorphic adenomas.     

The arteries of the lacrimal gland

Summary The vascularization of 70 lacrimal glands was studied by orbital dissection subsequent to injection of the arterial bed with red-dyed latex. The origin, diameter and collateral branches of the lacrimal artery and its anatomical relations were investigated. Three types of lacrimal vascularization were seen. In the type I variety, the lacrimal artery originates from the ophthalmic artery and runs along the margin of the rectus lateralis muscle. In this case, the lacrimal artery is a major source of vascular supply to the muscle. In the type II variety, the lacrimal artery originates from the middle meningeal artery. In this case, the lacrimal artery is only a very modest source of vascular supply to the muscle. The type III variety features two lacrimal arteries vascularizing the lacrimal gland. One of the arteries originates from the ophthalmic, while the other arises from the middle meningeal. In this case, the lacrimal gland is the site of an intraorbital anastomosis between the internal and external carotid systems. The lacrimal gland is innervated by the lacrimal nerve and the lacrimal rami of the maxillary nerve. Preliminary results regarding certain morphological features of the lacrimal nerve are reported in this paper.

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Les artères de la glande lacrymale

Résumé La vascularisation artérielle de 70 glandes lacrymales a été étudiée par dissection orbitaire, après injection du lit artériel par du latex coloré en rouge. L'origine, le calibre, les branches collatérales de l'artère lacrymale ainsi que ses rapports ont été notés. Les auteurs décrivent 3 types de vascularisation: Type I: l'artère lacrymale nait de l'artère ophtalmique, longe le bord supérieur du muscle droit latéral, dont elle assure en grande partie la vascularisation; Type II: l'artère lacrymale provient de l'artère méningée moyenne. Dans ce cas, elle ne participe que très modérément à la vascularisation musculaire. Type III: deux artères lacrymales assurent simultanément l'apport artériel glandulaire; l'une nait de l'artère ophtalmique et l'autre de l'artère méningée moyenne. La glande est alors le siège d'une anastomose intra-orbitaire entre les deux systèmes carotidiens interne et externe. L'innervation lacrymale est assurée par le nerf lacrymal et par des rameaux lacrymaux issus du nerf maxillaire. Quelques aspects morphologiques du nerf lacrymal sont rapportés, à titre préliminaire.

     

Morphogenesis of the human lacrimal gland

The aim of this study was to determine the main stages of the lacrimal gland's developmental process in humans and to establish its precise morphogenetic timetable. Its onset is generally assumed to take place at O'Rahilly's stage 21, arising from an epithelial thickening of the superior extreme of the temporary conjunctival fornix. However, the present study points to a prior stage in the process: the presence of epithelial-mesenchymal changes in embryos at O'Rahilly's stage 19. The study was performed using light microscopy on serial sections of 37 human specimens: 23 embryos and 14 fetuses ranging from 15 to 137 mm crown-rump length (7-116 weeks of development). Three stages in lacrimal gland morphogenesis were identified: (1) the presumptive glandular stage, O'Rahilly's stages 19-20, characterized by a thickening of the superior fornix epithelium together with surrounding mesenchymal condensation; (2) the bud stage, generally assumed to be the first manifestation of glandular origin, characterized initially by the appearance of nodular formations in the region of the superior conjunctival fornix and concluding with the appearance of lumina within the epithelial buds; and (3) the glandular maturity stage, weeks 9-16, the period in which the gland begins to take on the morphology of adulthood.     

Stimulus-permeability coupling in rat lacrimal gland

Incubation of isolated cells wtih 10(-2) M ethylene glycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid or cobalt inhibits 22Na and 45Ca uptake stimulated by carbachol. The artificial introduction of Ca into the cytosol by the cation ionophore A23187 also initiates the 22Na uptake. Amiloride (10(-5) M) partially inhibits 22Na uptake induced by carbachol, but has no effect on receptor-stimulated 45Ca uptake or 86Rb release. Tetrodotoxin (TTX) has no effect on 22Na uptake stimulated by carbachol, whereas methoxyverapamil (D 600) produces a small but significant decrease in both 22Na and 45Ca uptake. This effect of D 600 may be related to a block of receptor activation and not to a block of Ca channel activation. Incubation in high K (56 mM) does not prevent the change in membrane permeability to Ca, K, and Na initiated by carbachol. It is concluded that carbachol stimulates the influx of Ca; the rise in the cytosolic Ca concentration then couples receptor activation to a change in membrane permeability to K and Na. The permeability mechanisms for Ca, K, and Na that are activated by carbachol appear to be specific for each of the three cations and appear to be dissimilar to permeability mechanisms in excitable tissue that carry the same ions.     

Malignant myoepithelioma of the parotid gland: cytologic and histologic features

A case of malignant myoepithelioma of the parotid gland in a 34-year-old female is presented. In the fine-needle aspiration material, there was predominance of poorly cohesive polygonal cells with marked nuclear pleomorphism; no mitotic figures were observed. Focally, fragments of myxoid metachromatic intercellular material were also present. Histologically, the tumor was encepsulated, showing focal invasion of the capsule and tumor thrombi in the capsular vessels. The tumor was predominantly solid and myxoid, composed of cells with epithelioid features, marked anisonucleosis and a low mitotic activity. Immunohistochemically, the cells revealed positive staining for S-100 protein, vimentin, cytokeratins, glial acidic fibrillary protein and carcinoembryonic antigen; only several cell groups expressed smooth muscle actin and desmin; muscle specific actin was uniformly negative. In differential diagnosis, it was important to distinguish malignant myoepitelioma mainly from pleomorphic adenoma (mixed tumor), benign myoepithelioma, carcinoma ex pleomorphic adenoma and malignant melanoma. The criteria of malignancy in myoepithelial tumors are discussed.     

Primary ductal adenocarcinoma of the lacrimal gland

The morphological similarity of salivary and lachrymal gland tumors is known. Many clinicopathological studies and characteristics of salivary duct carcinoma, which bears histological similarlties to mammary duct carcinoma, have been recently reported; however, only one case of lacrimal duct carcinoma is reported. A second case of lacrimal duct carcinoma is presented. A 67-year-old male with a painlass mass in the right upper eyelid underwent total removal of the tumor mass. Microscopic examination of the tumor mass revealed ductal adenocarcinoma of the lacrimal gland, which was the equivalent of salivary duct carcinoma. The Immunohistological studies of the lacriml duct carcinoma showed similar results to those reported for salivary duct carcinoma. The recurrent tumor in the subdural spaces was removed 2 years after the initial surgery and the patient is followed as an outpatient.     

Primary De novo ductal adenocarcinoma of the lacrimal gland

BackgroundPrimary ductal adenocarcinoma of the lacrimal gland is a rare and aggressive malignant epithelial lacrimal gland neoplasm, morphologically and phenotypically resembles salivary duct carcinoma, and both strongly resemble infiltrating ductal carcinoma of breast.MethodRetrospective Chart review of cases of malignant lacrimal gland tumors from 2013 July to 2020 July. Authors describe the clinico radiological, morphological and immunohistochemical features of primary ductal adenocarcinoma (PDA) of lacrimal gland. Extensive review of literature of PDA of lacrimal gland and salivary gland ductal carcinoma has been performed.ResultsRetrospective chart review of the last 7 years yielded 22 malignant lacrimal gland neoplasms of which 4 cases demonstrated features of primary ductal adenocarcinoma of lacrimal gland, 2/4 cases showed an evidence of a pre existing pleomorphic adenoma and 2 were found to be de novo ductal adenocarcinomas. PDA of lacrimal gland showed expression of CK7, CK19, AR, HER2, cyclin D1 and were negative for CK5/14, CK 20, ER, PR, PSA, TTF-1, S-100 and SMA. Expression of GCDFP-15 was noted in one case. The presence of multiple events of loco-regional recurrences and/or distant metastasis necessitated a multidisciplinary approach.ConclusionsAuthors have expressed the need of clinical correlation; thorough tissue sampling and extensive immunohistochemical work up in identification of de novo PDA's and their molecular subtypes. A multi-institutional study might help in formulating the diagnostic criteria, identification of actionable targets, and thus study the role of targeted therapy in this rare and aggressive tumor which may result in better patient outcomes.     

Patterns of innervation of the lacrimal gland with clinical application

Parasympathetic stimulation of the lacrimal gland is responsible for tear production, and this innervation originates from fibers conveyed in the facial nerve. After synapse in the pterygopalatine ganglion, postsynaptic parasympathetic fibers travel within the zygomatic and zygomaticotemporal nerves (ZTN) into the orbit. As described in most anatomy texts, ZTN communicates with the lacrimal nerve (LN) posterior to the gland and then secretomotor fibers enter the gland. This study was performed to gain a better understanding of the innervation of the lacrimal gland. Seventeen cadaver heads were bisected for a total of 34 sides, which then underwent dissection of the superolateral orbital region to observe the course for the LN and ZTN. Three variations of the course of the LN and ZTN were found. In 20 (60.6%) dissections it was documented that the ZTN entered directly into the lacrimal gland with no communication with the LN. In 12 (36.4%) of the bisected heads, ZTN had both a direct connection into the gland and a communicating branch with the LN. In only one (3.0%) bisected head, ZTN communicated with the LN before entering the gland as it is commonly described in anatomy texts. Our study reveals that the ZTN usually takes a different course than is classically described in most anatomy textbooks. A greater understanding of the typical course these nerves take may help surgeons identify them more easily and avoid damaging them. Clin. Anat. 27:1174–1177, 2014. © 2014 Wiley Periodicals, Inc.