Melanocytoma of ciliary body and choroids simulating melanoma

Melanocytoma is a rare intraocular tumor. There are some reports in the literature dealing with primary melanocytomas of the choroid and ciliary body. It is believed that most of these tumors are clinically diagnosed as nevi or melanoma, and are followed up or treated without surgical resection, respectively. Some clinical features can give a clue as to the correct diagnosis.     

Immunoregulatory properties of bone marrow-derived cells in the iris and ciliary body.

Iris and ciliary body of mouse eyes have been examined for the presence of bone marrow-derived cells possessing the capability of functioning as antigen-presenting cells (APC). We have determined that iris and ciliary body contain significant numbers of cells bearing T200, indicating their bone marrow origin. Most of these express the F4/80 marker typically found on mature macrophages. However, approximately one-third of the cells express Ia and a similar number express Mac-1 markers. Virtually none of the cells express Thy-1 or surface immunoglobulin. Whole preparations of excised iris/ciliary body, or single cell suspensions prepared from these tissues were then assayed for their capacity to induce proliferation among allogeneic lymphocytes. It was discovered that iris/ciliary body tissues or cells did not function as alloantigen-presenting cells, although tissue and cells derived from the corneal limbus were allostimulatory. In addition, iris/ciliary body tissues and cells displayed the ability to suppress mixed lymphocyte reactions to which they had been added as regulatory cells. We conclude that normal iris and ciliary body contain bone marrow-derived cells that fail to function as alloantigen-presenting cells. However, cells were present that have the capacity to inhibit alloimmune lymphocyte proliferation. The strategic location of inhibitory cells in the tissues that line the anterior chamber of the eye raises the possibility that these cells may play a role in the phenomenon of immunological privilege that is characteristic of this site.     

Metastatic balloon cell malignant melanoma: a case report and literature review

A case of metastatic balloon cell malignant melanoma (BCMM) is presented. The balloon melanoma cells (BMC) were absent in the shave biopsy of the primary lesion and present as a minor component in the wide and deep excision. A subsequent right neck lymph node metastasis showed complete replacement of the lymph node by large, foamy cells. Though the tumor was amelanocytic and Fontana-Masson stain failed to reveal melanin, it stained positively for S-100, HMB-45, and Melan-A. Ultrastructurally, the foamy cells were characterized by cytoplasmic vacuolization and a lack of melanosomes. The differential diagnosis of metastatic balloon cell malignant melanoma is broad, and clinicopathologic correlation may play a critical role in achieving the correct diagnosis.     

Comparative analysis of progenitor cells isolated from the iris, pars plana, and ciliary body of the adult porcine eye

Photoreceptor loss causes irreversible blindness in many retinal diseases. The identification of suitable donor cell populations is of considerable interest because of their potential use to replace the photoreceptors lost in disease. Stem or progenitor cells that give rise to neurons and glia have been identified in several regions of the brain, including the embryonic retina and the ciliary epithelium of the adult eye, raising the possibility of autologous transplantation. However, there has been little systematic investigation into precisely which regions of the large mammalian adult eye give rise to such cells. Here, we show for the first time using the porcine eye the presence of progenitor cells in additional regions of the adult eye, including the pars plana and iris, regions that, in the human, are readily accessible during routine eye surgery. When cultured in the presence of growth factors, these cells proliferate to form neurospheres comprised of cells expressing retinal progenitor markers. Using an adherent monolayer culture system, these cells could be readily expanded to increase their number more than 1 million-fold and maintain a progenitor phenotype. When grown on the substrate laminin in the presence of serum, cells derived from both spheres and monolayer cultures differentiated into neurons and glia. These results suggest that a population of cells derived from the adult iris, pars plana, and ciliary body of a large mammalian species, the pig, has progenitor properties and neurogenic potential, thereby providing novel sources of donor cells for transplantation studies. Disclosure of potential conflicts of interest is found at the end of this article.     

Multiple forms of acetylcholinesterase in the ciliary ganglion and iris of the pigeon

Different methods of extraction and analysis have been used to investigate the cholinesterase activity of the ciliary ganglion and iris from the adult pigeon. The molecular forms of acetylcholinesterase in the extracts have also been separated either by gel electrophoresis or by sedimentation velocity in a density gradient. The activity and molecular forms in (i) a ‘soluble fraction’ (the high-speed supernatant of an isotonic sucrose homogenate) and (ii) a ‘Triton extract’ (as above, but with 0.2% Triton X-100 in the homogenate) were examined. The cholinesterase activity in whole homogenates and in the two extracts was characterized by enzyme kinetics and use of different substrates and inhibitors.In the iris, as distinct from the ganglion, the total cholinesterase activity involved a small but definite proportion attributable to a butyrylcholinesterase. In the soluble fraction from both ganglion and iris. which contained 13 and 29% of the total activity, respectively, either method of separation revealed three main molecular forms of acetylcholinesterase; the evidence suggests that these are size isomers. In addition, Triton X-100 extracts from ganglia were shown by electrophoresis to contain a fourth slow migrating component. This form contained most of the enzymic activity and appears to be a membrane-bound form of acetylcholinesterase; it was not detected in the iris.     

Proliferation and cell shape changes during ciliary body morphogenesis in the mouse.

Very little is known about the structure and development of the ciliary processes in the mouse eye. Our scanning electron microscope (SEM) studies reveal that, unlike other mammals, the ciliary processes form an irregular pattern, crossing over and interweaving rather than lying parallel to one another. Histological and SEM studies from embryonic day (E) 14.5 to postnatal day (P) 7 reveal that the first morphological sign of the ciliary zone is an annular bulge; this is then gradually molded to form discrete ciliary processes. The striking similarity between the developing capillary network and the adult ciliary folds suggests that the patterning template for the ciliary processes could be the underlying capillary network. Cell proliferation measurements and cell height assessments indicated that one of the first events occurring during the morphogenesis of ciliary processes is a proliferative surge around P0 in the outer ciliary epithelium. It is likely that this surge together with increasing cell heights leads to a bulging of this layer. After a slight delay, the inner ciliary epithelium responds by proliferating and extending inward toward the lens. Final shaping of the ciliary processes is achieved through cell height reductions in the inner ciliary epithelium. Thus, in the mouse, the temporal correlation between mitotic and cell height changes during ciliary body morphogenesis suggests that these processes play an integral role in the shaping of ciliary processes.     

Recurrent mesectodermal leiomyoma of the ciliary body: a case report

A 19-yr-old woman with a previous history of a mass of the right ciliary body presented with a decreased visual acuity of right eye. Clinicoradiologic examinations suggested a recurrent mass of the ciliary body. Enucleation of the right eye was performed under the impression of malignant tumor. On microscopic examination, the tumor was a mesectodermal leiomyoma of the ciliary body. On immunohistochemistry, the tumor cells were reactive to smooth muscle actin and vimentin, but not reactive to cytokeratin, S-100 protein, neurofilament, desmin, epithelial membrane antigen, HMB-45, glial fibrillary acidic protein, and synaptophysin. Electron microscopy revealed numerous thin longitudinally placed myofilaments and focal densities in the cytoplasms. In the review of the literature, only 27 cases of mesectodermal leiomyoma of the ciliary body were reported, however, there was no report of recurrent cases. Mesectodermal leiomyoma should be differentiated from other orbital spindle-cell tumors such as amelanotic melanomas and glial tumors. Immunohistochemical and electron microscopic studies may be useful for the correct diagnosis by showing smooth muscle differentiation in the tumor cells.     

Small intestinal lesion resembling graft-vs-host disease. A case report in immunodeficiency and review of the literature

We report graft-vs-host disease-like histology in a small intestinal biopsy specimen that was obtained from a patient with common variable immunodeficiency and related T-cell defect. We include findings from immunohistochemical studies and follow-up information. Review of the literature yielded only a small number of histologically documented cases of this lesion without previous bone marrow transplantation. Awareness of this clinicopathologic entity is important in the interpretation of gastrointestinal biopsy specimens.     

Balloon cell nevus of the iris

Balloon cell nevus is a rare histopathological lesion characterized by a predominance of large, vesicular and clear cells, called balloon cells. There is only 1 case of balloon cell nevus of the iris reported in the literature.Case reportA 55 year-old man presented a pigmented elevated lesion in the right iris since the age of 12 years old. The lesion had been growing for the past 2 years and excision was performed. Histopathological examination showed a balloon cell nevus composed of clear and vacuolated cells without atypia. A typical spindle cell nevus of the iris was also observed. The differential diagnosis included xanthomatous lesions, brown adipocyte or other adipocytic lesions, clear cell hidradenoma, metastatic clear cell carcinoma of the kidney and clear cell sarcoma. The tumor was positive for Melan A, S100 protein and HMB45.ConclusionBalloon cell nevus of the iris is rare but should be considered in the differential diagnosis of melanocytic lesions of the iris.     

Endobronchial plasma cell granuloma (xanthomatous pseudotumor): A light and electron microscopic study

Plasma cell granuloma (xanthomatous pseudotumor) is polymorphic at light as well as electron microscopic examination. At light microscopy the endobronchial variant of this entity was rich in plasma cells and interwoven, whorllike, or concentrically arranged spindle cells. Foamy histiocytes and macrophages usually abundant in the intrapulmonary variant were rare. At electron microscopy particles 20 to 50 nm. in size were found at the bronchial mucosal surface but not elsewhere in the lesion. Plasma cells near the bronchial surface contained cytoplasmic fibrils, mitochondria with concentric cristae, and inclusions that bore a close resemblance to adjacent extracellular crystallized hemoglobin. Those in the center of the lesion contained ordinary round inclusions and none of the other changes. Spindle cells in the interlaced areas were mostly fibroblasts or myofibroblasts, whereas those whorled around capillaries resembled pericytes with basement membranes and nuxes-like intercellular junctions. Year rings like multilayered basal laminae were frequently present between the pericyte-like cells and the endothelial cells of the capillaries. The ultrastructure of plasma cell granuloma, like the histologic and clinical aspects, differs from that of sclerosing hemangioma, pseudolymphoma, and malignant plasma cell tumor affecting the lung.     

Polypoid (pedunculated) subepicardial lipoma: a cardiac lesion resembling the epiploic appendage.

This report describes a 75-year-old woman with an asymptomatic pedunculated lipoma involving the epicardium of the right atrium. The lipoma was an incidental finding at autopsy. The twisted lesion showed many similarities with the infarcted epiploic appendages observed in the visceral peritoneum.     

Mesectodermal leiomyoma of the ciliary body: report of a case and review of the literature

Mesectodermal leiomyoma of the ciliary body is a rare benign tumor with double (muscular and neural) differentiation. This neoplasm is considered to originate from the ciliary body smooth muscle, a neural crest derivative. We report a case of mesectodermal leiomyoma of the right eye occurring in a 53-year-old woman, who presented with significant decrease of visual acuity. A malignant melanoma was highly suspected on clinical evaluation, and the globe was enucleated. The tumor measured 1.2cm in greatest dimension, and consisted of spindle and ovoid cells with abundant fibrillary cytoplasmic processes. Immunohistochemical stains revealed positivity for smooth muscle actin, caldesmon, neuron-specific enolase, and CD56 antigen. A review of the 23 cases thus far reported in the literature shows a striking predilection for women, as well as significant difficulties in differentiating this tumor from malignant melanoma on clinical grounds.     

Fine-needle aspiration biopsy of metastatic malignant melanoma resembling a malignant peripheral nerve sheath tumor

We report a case of metastatic malignant melanoma resembling a malignant peripheral sheath tumor, which posed a significant diagnostic challenge. The patient is a 76-year-old male, who presented in the emergency room with bilateral chest pain exacerbated by inspiration. The pain was present for 3 week and was not exacerbated by physical exercise. The diagnostic workup revealed bilateral parenchymal pulmonary infiltrates. The CT-scan guided fine-needle aspiration and the core biopsies of the largest pulmonary lesion revealed high-grade spindle cell neoplasm with individual cell apoptosis and necrosis. The immunohistochemical profile on the cell block showed that the cells are positive for Vimentin. The S-100 stain showed only focal positivity. The immunohistochemical stains for HMB45, Melan A, pancytokeratin, and smooth muscle actin were negative. Five years ago the patient was diagnosed with melanoma on the back with Clark level of IV. The melanoma was excised with clear margins and sentinel lymph nodes were negative. Careful examination of patient's previous slides revealed an area of spindle cell melanoma adjacent to a nodular type melanoma. Based on the patient's previous history, current clinico-pathologic presentation and immunohistochemical profile, the diagnosis of metastatic malignant melanoma resembling peripheral nerve sheath tumor was favored over the diagnosis of metastatic malignant spindle cell neoplasm of unknown primary site, which by itself is very rare clinical scenario.     

Vacuolated cell mesothelioma of the pericardium resembling liposarcoma: a case report

We report a case of localized pericardial mesothelioma with unusual histological features in a 44-year-old woman. Her radiological imagings showed an 11-cm pericardial tumor, between the heart and aortic arch. Microscopically, the tumor was predominantly composed of vacuolated cells and vaguely reminiscent of well differentiated "lipoma-like" liposarcoma, but only small foci of the tumor showed the papillotubular configuration. Histochemically, the tumor cells contained hyaluronic acid in the vacuoles but no lipids. Immunohistochemically, they showed immunoreactivity for cytokeratin, calretinin, vimentin, and epithelial membrane antigen. Ultrastructural study showed that the vacuoles of the tumor cells were intracytoplasmic lumina. The intracytoplasmic lumina and the surface membranes of the tumor cells had many long and slender microvilli with focal bush-like appearance. Desmosomes between adjacent cells were occasionally observed. To our knowledge, this is the first case report of epithelial type mesothelioma predominantly composed of vacuolated tumor cells, microscopically mimicking liposarcoma.