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La hiperplasia angiolinfoide con eosinofilia (HALE) es una proliferación vascular benigna caracterizada por lesiones angiomatosas solitarias o múltiples, que se presentan más frecuentemente en mujeres jóvenes o de mediana edad, en cabeza y cuello, con predilección por la región periauricular. Esta enfermedad plantea un diagnóstico diferencial extenso, tanto con lesiones benignas como malignas, por lo que la posibilidad de tener una herramienta diagnóstica no invasiva como la ecografía puede ser de utilidad. Presentamos una serie de casos de HALE con morfología ecográfica "en placa pseudonodular hipervascular" de localización periauricular, con correlación clínica e histológica. Se demostró comunicación vascular ecográfica entre lesiones que parecían clínicamente separadas. El conocimiento de esta forma de presentación ecográfica podría contribuir a mejorar la precisión del diagnóstico y seguimiento evolutivo de estos casos

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a benign vascular proliferation characterized by solitary or multiple angiomatous lesions. It is most common in young or middle-aged women, and the lesions typically affect the head and neck, showing a particular predilection for the periauricular region. The differential diagnosis in patients with ALHE is broad and includes both benign and malignant conditions. We report on a series of cases of periauricular ALHE in which ultrasound imaging revealed an hypervascular, pseudonodular and plaque-like morphology with clinical and histologic correlations. It also evidenced vascular communication between lesions that appeared to be separate on clinical examination. Familiarity with such ultrasound presentations could help to improve diagnostic accuracy and facilitate disease monitoring in patients with ALHE

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The authors report the ultrastructural characteristics of myopericytoma, a recently described variant of perivascular (pericytic) tumors, mainly with regard to their myopericytic cells and vessels. Myopericytes range between pericytes and vascular smooth muscle cells (SMCs) in a morphologic continuum. The principal findings of the intermediate phenotypes are (1) elongated or annular morphology with processes of varying length and thickness (usually long and thin); (2) a continuous, irregularly thickened and zonally duplicated basement membrane; (3) heterocellular "peg and socket" junctions with neighboring endothelial cells, and scarce specialized junctions between myopericytes; (4) numerous micropinocytotic vesicles, whether continuous or forming focal rows; (5) abundant thin microfilaments, grouped in bundles with dense bodies and adhesion plaques; (6) poorly developed synthetic system (RER and Golgi); (7) pseudointracellular bodies formed by invagination of basement and plasma membranes, with numerous endocytic vesicles; and (8) zones of cytoplasmic rarefaction near micropinocytotic vesicles and intracellular organelles. The ultrastructure of myopericytes therefore makes it possible to distinguish them from pericytes, SMCs, and fibroblast/myofibroblasts, which is useful for myopericytoma diagnosis. The main pattern of the vessels, with perivascular concentric and multilayered growth of myopericytes (a thick wall in contrast to a small lumen) and lack of elastic material, also supports an intermediate form between pericytic and muscular microvasculature. The presence of myopericytes more similar to SMCs and of hemangiopericytoma-like vessels concurs with transitional forms with angioleyomyoma and true hemangiopericytoma, histogenetically representing a morphologic continuum for the perivascular tumors.

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Myopericytoma is a perivascular tumor that has been recently described in humans, but not in laboratory rodents. The authors encountered an intra-abdominal tumor resembling human malignant myopericytoma in a Fischer rat. Grossly, the tumor was found as two brown-colored masses located in the mesentery of rectum. Microscopically, the tumor was composed of oval to spindle-shaped cells, which were arranged in sheets around numerous thin-walled branching vessels and partly showed a concentric perivascular growth pattern. Mitoses were frequently seen, and the tumor cells showed a local invasion. Immunohistochemically, the tumor cells were strongly positive for alpha-smooth muscle actin and weakly positive for vimentin and desmin. Ultrastructurally, the tumor cells had dendritic processes, actin-like thin filaments with dense bodies, basement membranes, hemidesmosomes, and micropinocytotic vesicles. These findings suggest that the most appropriate term for diagnosis of the present case could be a malignant myopericytoma.

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BACKGROUND: Angiosarcomas arise in the scalp and face in the elderly, in association with chronic lymphedema (Stewart-Treves syndrome), and in irradiated areas. Rarely in these settings, angiosarcomas exhibit pure spindle cell phenotype. METHODS: Herein, the clinicopathologic features of a 72-year-old-woman with spindle cell angiosarcoma are described. RESULTS: A 72-year-old woman presented with numerous nodules and diffuse induration from the lower abdomen to the right buttock, corresponding to the area exposed to 60Co-irradiation during treatment for cervical carcinoma 10 years earlier. Histopathological examination revealed inflitrative, atypical, spindle cells that labeled with antibodies to CD31, CD34, and factor VIII-related antigen. Ultrastructurally, these malignant spindle cells contained Weibel-Palade bodies. No features suggesting radiation dermatitis (sclerosis or bizarre, large fibroblasts) were identified, but lymphangiectases and widely spaced collagen bundles(lymphedema) were prominent in the skin surrounding the angiosarcoma. Computed tomographic scan of the abdomen highlighted this histologic finding by demonstrating tumor masses limited to areas of lymphedema. Treatment with intravenous and local injections of recombinant interleukin 2 (rIL 2) followed by electron beam irradiation were initially effective with tumor remission for 2 months. However, the recurrent tumor did not respond to a second course of one-shot injection of rIL 2 through the abdominal aorta and the patient succumbed to her angiosarcoma 19 months after diagnosis. CONCLUSIONS: Radiation-induced lymphedema may be a factor in angiosarcoma associated with radiotherapy.

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A case of very rare uterine clear cell epithelioid leiomyomatosis is reported. The patient presented with a recurrent pelvic mass after hysterectomy 2 years earlier. The recurrent tumor was located mainly in the vessels of the broad ligament as worm-like plugs. The reviewed hysterectomy specimen showed a typical multi-lobulated intramural mass together with worm-like plugs within the myometrial vessels. Computer tomography exhibited metastatic nodules in both lungs. According to an histological examination, all the tumor cells were of epithelioid type and contained abundant clear cytoplasm. Characteristic large, thick-walled blood vessels were observed. Immunohistochemical staining and ultrastructural examination supported smooth-muscle origin in this case. Electron microscopic study revealed that the clear cytoplasm was attributed to the presence of numerous dilated mitochondria that had lost their cristae. The patient is still alive with the disease 28 months after surgery.

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An electron microscopic study was carried out of different kinds of hemangiomas (capillary, cavernous and combined) in 18 children at the age of two months up to one year. Centers of differently expressed proliferation both of the endothelial cells and pericytes were found. The proliferation was most distinctly expressed in the capillary and cavernous hemangiomas. At the later stages, regressive and involutive changes, presented better in the capillary hemangiomas, were observed. The authors consider that hemangiomas, irrespective of their active cell growth, are tumours with a good prognosis.

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Among all neoplasms of the mediastinum, those composed of mesenchymal elements, and arising primarily in mediastinal soft tissue, are the least common group of tumors discussed in this issue of Seminars. Apart from tumors of nerve sheath, neuroectoderm, adipose tissue, and lymphatic vessels, few of them will comprise a significant part of the surgical pathologist's practice. Yet each poses two important clinical problems: the recognition of visceral-associated (as opposed to primary soft tissue) lesions, and the exclusion of metastases from an extrathoracic site. In this review, the histologic, immunohistochemical, and ultrastructural features that characterize mediastinal soft tissue tumors will be emphasized. Clinical aspects of these lesions are also discussed, particularly as they may relate to the aforementioned clinical questions.

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A case of a primary undifferentiated sarcoma of the descending thoracic aorta in a 75-year-old man is reported. Intraluminal growth and occlusion produced congestive heart failure and renal failure. The thoracic aorta was relatively normal on chest radiography so that the lesion was undiscovered until the autopsy. To our knowledge, it is the first case of a primary undifferentiated sarcoma of the thoracic aorta, and the first undifferentiated aortic sarcoma to be examined with immunohistochemistry and electron microscopy. Electron microscopy and immunohistochemistry verified the sarcomatous nature of the undifferentiated neoplasm.

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A variable number of soft-tissue tumors, depending largely on the experience of the pathologist, cannot be precisely classified by light microscopy, and electron microscopy and/or immunocytochemistry may be required. The applications and limitations of these techniques in the diagnosis of selected soft-tissue tumors are briefly reviewed.

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The fine structural features of microcirculation in benign gliomas, as compared to those in glioblastomas have insufficiently been studied. 36 astrocytomas and oligoastrocytomas (grades I and II) were examined with the electron microscope in order to classify the arterioles, capillaries and venules of these tumours. In all the gliomas, the number of arterioles was smaller than in the normal brain parenchyma. A thickening of the subendothelial basement membrane could be assessed regularly. In the architecture of the small vessels numerous transitional forms could be found in many cases. On this basis the designation "capillary-like" and "venule-like" vessels seems to be justified. As a rule, the venule-like vessels are more numerous than the capillaries. The pericapillary and particularly the perivenular spaces are frequently dilated. In a few areas no continuous perivascular sheath of astrocytic foot processes are formed. At places glial processes can be found in the perivascular spaces which are not covered by a basement membrane. Lack of arterioles can lead to disturbances in autoregulation, and the frequently pathological structure of the capillaries and venules can result in disordered transport of water and ions with consecutive oedema.

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The origin of Kaposi's sarcoma from the endothelium and fibroblast-like cells of a vascular wall is proven on the basis of complex pathomorphological, immunomorphological, autoradiographic and electron microscopical investigation of tumour biopsies. Depending upon the predominating cell type of origin, the tumour in its different parts, may form the structures of either different variants of angiomas or fibrosarcomas.

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The monograph summarizes the most important data and experience based on the clinicopathological analysis, histological and histoenzymatic examinations of more than 1000 primary tumours and 400 tumour-like lesions of bones. The diagnosis of them has been based on the WHO classification of bone tumours which appeared to be the best in meeting the needs of diagnostic practice. However, in our collection of cases also occurred such cases which did not fit into the WHO diagnostic scheme. They included lesions the separate existence of which could be proved only recently or has remained the matter of discussion, such as periosteal osteosarcoma, clear-cell and dedifferentiated chondrosarcoma, malignant fibrous histiocytoma, the so-called parachordoma, resorptive giant-cell granuloma, reactive periostitis of tubular bones of hands and feet, and the tibial lesion reminiscent of cementifying fibroma. In the majority of types of the tumours and tumour-like lesions of bones electron microscopical examination was carried out (203 cases), the results of which are presented here in a considerable extent. On the one hand, electron microscopy facilitated the diagnosis in some cases, and, on the other hand, it proved as extremely important in solving the problems of histogenesis of some of the lesions.

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Thirteen angiogenic tumours of soft tissues (benign and malignant variants of these neoplasms) were studied electron microscopically. The data obtained indicate that an electron microscopic examination allows performing differential diagnosis within the group of angiogenic tumours and distinguishing them from the neoplasms of other histogenesis.

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This report presents a rare malignant endothelial neoplasm which arose at the site of a pre-existing lymphangioma. The lymphangioma was located on the right buccal mucosa, and the malignant neoplasm arose 17 years after irradiation of the initial tumor. Clinical, light microscopic and immunohistochemical (Factor VIII-related antigen and Ulex europaeus Agglutinin-I) studies were made, together with observations by transmission and scanning electron microscopy. These studies provide evidence that this malignant neoplasm was well-differentiated and had not yet lost the characteristics of normal lymphatic cells.

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Mice and rats were injected intracerebrally with Harvey or Kirsten murine sarcoma viruses at 2 or 10 days after birth. Animals exhibited neurologic symptoms at 10 to 30 days postinjection. Brains, livers, and spleens were examined grossly and by light and electron microscopy. Mice injected at 2 days and rats injected at 10 days developed multiple brain neoplasms derived from endothelial cells. This conclusion was reinforced by immunofluorescence studies showing factor VIII expression on transformed cells both in vivo and in vitro. Brains of rats injected at 2 days contained both transformed endothelial and astroglial elements. Ultrastructural evidence for murine sarcoma virus replication was found in endothelial and glial cells of animals injected at 2 days; however, such evidence was not found in those injected at 10 days of age. The type of neoplasm induced appeared to be independent of concentration of inoculum, genetic strain within a species, or type of helper virus pseudotyped with the murine sarcoma virus. This system may facilitate the investigation of endothelial function and neoplasia.

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We studied the electron microscopy of two tumors which clinically and histologically conformed to what has been described as angiomatoid fibrous histiocytoma, a tumor thought to be of fibrohistiocytic origin. The ultrastructure of one tumor was that of a cellular angioma and the second tumor a vascular lesion with fibroblasts and histiocyte-like mononuclear cells. Our findings suggest that angiomatoid fibrous histiocytomas are basically vascular tumors with fibroblasts and other cells as secondary participants in some lesions. The behaviour of angiomatoid fibrous histiocytoma cannot be predicted from histology. Our findings of different ultrastructural components in histologically non-separable tumors lead to a question whether different ultrastructural composition is correlated with different biological behavior of these tumors. Further studies of similar cases are required if tumor morphology is to be correlated with clinical behavior.

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