Cardiac myxoma with glandular differentiation: an immunohistochemical and ultrastructural study.

A case of cardiac myxoma with glandular differentiation is reported. The patient did not have elements of the Carney triad or syndrome. The tumor was mainly composed of characteristic stellate cells in a focally collagenized, myxoid stroma, along with aggregates of glandular-forming epithelial cells, with mucin-containing intra- and intercellular lumina. Ultrastructurally, these gland spaces displayed short, straight microvilli and junctional complexes. The epithelial cells were positive for cytokeratin 7 and negative for cytokeratin 20. Calretinin was positive in the stellate cells and negative in the epithelial component. The potential origin from pluripotent mesenchymal cells or from seeded stem cells is hypothesized for glandular differentiation in myxomas. Further studies are required to unravel the relationship between stellate cells and the diverse heterologous components reported in these tumors.

A novel kind of tumor type-characteristic junction: plakophilin-2 as a major protein of adherens junctions in cardiac myxomata.

Using novel antibodies of high avidity to--and specificity for--the constitutive desmosomal plaque protein, plakophilin-2 (Pkp2), in a systematic study of the molecular composition of junctions connecting the cells of soft tissue tumors, we have discovered with immunocytochemical, biochemical and electron microscopical methods, a novel type of adherens junctions in all 32 cardiac myxomata examined. These junctions contain cadherin-11 as their major transmembrane glycoprotein, which we could repeatedly show in colocalization with N-cadherin, anchored in a cytoplasmic plaque formed by α- and ß-catenin, together with the further armadillo-type proteins plakoglobin, p120, p0071 and ARVCF. Surprisingly, all adherens junctions of these tumors contained, in addition, another major armadillo protein Pkp2, hitherto known as an obligatory and characteristic constituent of desmosomes in epithelium-derived tumors. We have not detected Pkp2 in a series of noncardiac myxomata studied in parallel. Therefore, we conclude that this acquisition of Pkp2, which we have recently also observed in some mesenchymally derived cells growing in culture, can also occur in tumorigenic transformations in situ. We propose to examine the marker value of Pkp2 in clinical diagnoses of cardiac myxomata and to develop Pkp2-targeted therapeutic reagents.

Myxoma of the penis in an African pygmy hedgehog (Atelerix albiventris).

A penile tumor (4 × 2.5 × 1 cm) was surgically removed from an African pygmy hedgehog (Atelerix albiventris) aged 3 years and 5 months. The tumor was continuous with the dorsal fascia of the penile head. Histopathologically, tumor cells were pleomorphic (oval-, short spindle- and star-shaped cells) with low cell density. Abundant edematous stroma was weakly positive for Alcian blue staining and positive for colloidal iron reaction. Tumor cells displayed no cellular atypia or karyokinesis. Tumor cell cytoplasm was positive for vimentin antibody, while cytoplasm and nuclei were positive for S-100 protein antibody. Tumor cell ultrastructure matched that of fibroblasts, and the rough endoplasmic reticulum was enlarged. The tumor was diagnosed as myxoma. This represents the first report of myxoma in a hedgehog.

Histogenesis of morphologic variations in tumors of the uterine wall.

We investigated seven uterine wall lesions, selected because of the presence of unexpected patterns or components, to determine their relationship to normal uterine constituents. These lesions included a bizarre leiomyoma, a palisading leiomyoma which resembled a schwannoma, two myxomas, irradiated myometrium, a plexiform tumor, and a leiomyoma with tubular structures. All of these lesions except for the epithelial component of the plexiform tumor showed ultrastructural characteristics of smooth muscle, demonstrating a common origin from the myometrium. Two tumors, the plexiform tumor and the leiomyoma with tubules, had the pattern of epithelial structures suggesting origin from müllerian mesencyme: the plexiform tumor resembled incompletely differentiated endometrium and the tubular structures in the leiomyoma had features of mesothelium. We conclude that these varied and often confusing morphologic patterns reflect the capacity of uterine smooth muscle and stroma to undergo a wide spectrum of alterations including differentiation toward epithelial structures. Changes of this type occur in benign and malignant uterine stromal neoplasms and do not in themselves have prognostic significance.

Metastasizing atrial myxoma.

Tumors that were identical in morphology to a previously excised atrial myxoma were found in the choroid plexus and the scapula of a 46-year-old woman 8 and 10.5 years, respectively, after cardiac surgery. Ultrastructurally the scapular lesion resembled previously reported atrial myxomas. This case demonstrates that atrial myxoma is a true neoplasm capable of metastatic spread despite its slow growth and innocuous histologic appearance.

Scanning electron microscopy of intracardiac myxoma.

Scanning electron microscopy was utilized to study the surface morphology of intracardiac myxomas and to compare it with that of an atrial thrombus. The thrombus was only partially endothelialized, whereas myxomas were almost always completely covered by endothelial cells. Endothelium-lined crevices and clefts were a striking feature of the myxoma, and they were not seen in the atrial thrombus. In areas where the surface endothelium was denuded, fibrin and platelet aggregates were noted in both the myxoma and the thrombus.

Cardiac myxoma with chondroid features: a light and electron microscopic study.

The first case of a cardiac myxoma exhibiting chondroid differentiation is described. The tumor showed lacunar spaces around clusters of typical myxoma cells on light microscopy. Ultrastructurally the tumor cells contained abundant glycogen, and the tumor stroma contained proteoglycan granules identical to those seen in the ground substance of cartilage. These findings lend further support to the belief that the primitive mesenchymal cell is the cell of origin in cardiac myxoma.

Aggressive angiomyxoma of pelvic soft parts: a clinicopathologic study of nine cases.

Nine cases of aggressive angiomyxoma (AAM) of the pelvic soft parts were studied by light and electron microscopy and immunohistochemistry. The tumors were confined to the vulva, vagina, pelvic floor, and perineum in the seven women. The perineum and the para-anal region were involved in the two men. The patients ranged in age from 18 to 63 years. Aggressive angiomyxoma presented as a slowly growing, polypoid or cyst-like tumor. Six of the nine cases were followed up; all of the tumors recurred within nine to 84 months, and one recurred for the second time at 144 months. Recurrences were attributed to incomplete tumor excision. None of the six patients died or had metastases. The aggressive angiomyxomas had infiltrative borders and rubbery, white or soft, gelatinous cut surfaces. Histologically, the lesions were composed of stellate and spindle-shaped neoplastic cells embedded in a collagenous and hyaluronic acid-containing stroma. Nuclear atypia and mitoses were absent. Typically, the lesions had an important vascular component, often displaying medial hypertrophy and vascular grouping. Ultrastructurally, the neoplastic cells resembled fibroblasts rather than myofibroblasts. They showed strong immunoreactivity for actin but were negative for S-100 protein, Factor VIII, carcinoembryonic antigen, and keratin. The morphoimmunocytochemical characteristics of AAM cells favor a fibroblastic origin and differentiation. Aggressive angiomyxoma should be distinguished from the more common benign and malignant myxoid neoplasms or tumor-like conditions of the pelvic soft parts. Recurrence of AAM may be avoided by wide, local excision.

Aggressive angiomyxoma of the vulva: an unusual, deceptive and recurrence-prone tumour with evidence of estrogen receptor expression. Case report.

Positive staining for estrogen receptors is reported in a new case of aggressive angiomyxoma of the vulva. Clinical, light- and electron microscopic features as well as immunohistochemical reactions in this case are compared with the 28 earlier published cases, and the main differential diagnosis, angiomyofibroblastoma of the vulva, is discussed.

Conjunctival myxoma. A clinicopathologic study of four cases and a review of the literature.

Myxomas are benign tumors that resemble a primitive mesenchyma and rarely occur in the conjunctiva. A clinicopathologic study of four new cases is reported, with a review of the clinical, structural, and behavioral characteristics of the previously reported eight cases. In this study, histochemical analysis of the mucous substance indicated that hyaluronic acid and chondroitin sulfates were present. On ultrastructural examination, the myxoma cell had secretory vacuoles and numerous intermediate-sized cytoplasmic filaments. Adults of an average age of 50.8 years were most often affected. The most common initial complaint was of a painless, slow-growing conjunctival mass, present for an average of 31 months. These tumors typically had a smooth, fleshy, gelatinous appearance. The high recurrence rate that has been noted in orbital and cardiac myxomas was not a feature of these conjunctival myxomas. With an average follow-up of 29 months, a single excision appeared to have been adequate treatment.

Intraspinal neurothekeoma (nerve sheath myxoma). A report of two cases.

Neurothekeomas (nerve sheath myxomas) are rare benign cutaneous tumors. The authors describe two spinal intradural cases that show histologic, immunohistochemical, and electron microscopic features identical to their cutaneous counterparts. The authors' findings suggest histogenesis from Schwann's cells or undifferentiated nerve sheath precursor cells. Neurothekeomas in unusual locations should be differentiated from myxoid neurofibromas, perineuriomas, and soft tissue myxomas.

Ultrastructure abnormalities in proteoglycans, collagen fibrils, and elastic fibers in normal and myxomatous mitral valve chordae tendineae.

Normal and myxomatous chordae tendineae were studied using light and electron microscopy, to assess the alterations in the appearance and mutual arrangement of proteoglycans, collagen fibrils, and elastic fibers. Specific staining with ruthenium red and cuprolinic blue in a critical electrolyte concentration mode were used to localize proteoglycans. Fresh tissues were fixed in glutaraldehyde containing the cationic dyes and embedded into Spurr resin. Semithin sections of LR White (London Resin Co., Basingstoke, U.K.)-embedded tissue were used for histochemistry. In normal chordae tendineae, the fibrosa comprised close-packed collagen fibrils intermixed with elastic fibers. These were surrounded by a thin layer of elastic fibers and collagen fibrils, both of which were closely associated with proteoglycans. In myxomatous chordae tendineae, alterations were observed in the connective tissue. Proteoglycans were more abundant and were distributed throughout the tissue. The outermost layer was transformed into an undifferentiated electron-dense mass surrounding the central fibrosa, which contained degraded elastic fibers and collagen fibrils. Collagen fibrils had faint banding or lacked a banding pattern altogether. Spaces between collagen fibrils were occupied by abnormal proteoglycans or proteoglycan aggregates. Elastic fibers showed varying degrees of degeneration and were occasionally replaced by electron-lucent spaces containing microfibrils. Accumulation of abnormal proteoglycan was also observed around degenerated elastic fibres and collagen fibrils.

Atrial myxoma with remote metastasis: case report and review of the literature.

The occurrence of a metastatic atrial myxoma after complete resection of the intracardiac lesion is rare. We treated a 66-year-old man who 13 years earlier had undergone resection of a left atrial myxoma, which had been diagnosed during a work-up of symptomatic cerebellar infarcts. He initially had a painless nonpulsatile mass near the radial artery. Surgery was performed to confirm the presumptive diagnosis of calcified ganglion, and subsequently he was found to have a pseudoaneurysm. The pathologic examination identified the tissue as myxoma. The results of echocardiography and cardiac magnetic resonance imaging failed to reveal any residual or new intracardiac tumor. The patient subsequently experienced swelling of the right leg and was found to have a 6 x 10 cm mass in the medial portion of his proximal thigh. At exploration this mass was found to extend from the profunda femoris artery, and it also compressed the femoral vein. Pathologic evaluation based on histologic and electron microscopic features of this lesion confirmed this lesion to be myxoma. Review of the literature reveals that metastatic atrial myxoma is a rare lesion, and such a delayed occurrence after resection of the cardiac lesion has been infrequently reported. This suggests that patients with atrial myxoma may be at risk for the appearance of intravascular metastatic tumor long after resection of their original intracardiac tumor.

Cardiac myxoma.

Ten patients with cardiac myxoma were reviewed. The ranged from 23 months to 60 years old. Echocardiography was the most helpful noninvasive diagnostic technique. The tumor was demonstrated by angiocardiography, left atrial myxomas frequently migrating to the left ventricle in diastole. Hemodynamically, left atrial myxomas were associated with moderately severe pulmonary hypertension and simulated mitral stenosis or insufficiency and right atrial myxomas, with right atrial hypertension. There were 7 myxomas in the left atrium, 2 in the right atrium, and 1 in the right ventricle. Eight patients underwent open-heart operation with removal of the myxoma, 1 had concomitant tricuspid valve replacement, and 1 had biopsy of the right ventricle only. The other patient was a Jehovah's Witness and refused operation. One patient died of cardiac arrest intraoperatively, and another died of a bilateral cerebral infarct. One patient had recurrence requiring reoperation. Postoperative hemodynamic and clinical improvement was more striking in patients with a left atrial myxoma presumably due to a normal mitral valve in contradistinction to the tricuspid valve.

Conjunctival myxoma: a case report.

A rare case of conjunctival myxoma in an 18-year-old female is reported. Clinically it presented as a painless mass located in the nasal bulbar conjunctiva. It was composed of spindle and stellate shaped cells in a loose mucoid stroma. Some of the cells had intracytoplasmic vacuoles consistent with dilated rough endoplasmic reticulum and/or intranuclear vacuoles of nuclear membrane invaginations. Mast cells were also seen in the stroma. No recurrence has been reported eight months postoperatively.

Myxoma of the breast: report of a case and ultrastructural study.

A case of myxoma of the breast is presented. The differential diagnosis with respect to other myxoid tumours of the breast is discussed. Ultrastructurally the tumour cells show features of a primitive mesenchymal cell with possible pericytic or modified myoepithelial cell differentiation. The histogenesis is discussed.

Corneal myxoma. Case report and review of the literature.

Myxoma of the cornea is extremely rare. To our knowledge, only two cases have been reported in the literature. We report an additional case of a corneal myxomatous lesion that presented as a subepithelial, gelatinous, and whitish mass. Histologic examination revealed a loose mucoid stroma, rich in hyaluronic acid, with a relative paucity of cells.

Cardiac myxoma with Gamna-Gandy bodies: case report with MR imaging.

We describe a patient with a left atrial tumor that showed very unusual magnetic resonance (MR) imaging features. Postsurgical histologic examination showed characteristics of myxoma, and Gamna-Gandy bodies were found in the tumor. We believe that the unusual MR appearance was caused by the hemosiderin in the Gamna-Gandy bodies.

Don't confuse dental soft tissues with odontogenic tumors.

Surgical pathologists are cautioned against the misinterpretation of immature dental tissues (dental papillae and follicles) and dental pulp as odontogenic tumors, especially odontogenic myxomas and fibromas. The close histologic similarity of the immature tissues to tumors may require a clinical-radiologic correlation with the histopathologic specimen in order to distinguish the locally aggressive tumors from innocuous dental tissues.

Dermal nerve sheath myxoma.

A case of dermal nerve sheath myxoma on the left palm of 26-year-old Japanese man is presented. We examined this tumor by light and electron microscopies. On light microscopic examination, this tumor was characterized by a multilobulated myxoid tumor composed of stellate cells in an abundant mucous matrix. This histological feature resembled previously reported cases of dermal nerve sheath myxoma. On electron microscopic examination, the findings of these tumor cells were similar to those of the perineurial cells. These microscopical examinations have provided evidence for an origin from perineurial cells rather than Schwann cells.