Differentiation, histogenesis and morphogenesis: their implications for tumor diagnosis.

Differentiation, as employed in tumor classification for histopathology, refers to the resemblance of neoplastic cells to their presumed cell/tissue of origin. Since differentiation for diagnosis is obtained by analysing histological images, this histogenetic concept creates practical limitations. Morphogenesis, a variant of differentiation, is a wider concept since it takes into consideration the nature of the tumor cells, their organization and their synthetic products. Consequently, morphogenesis, rather than differentiation, seems to be a better predictor of histogenesis in tumor diagnosis.

Contribution of transmission electron microscopy to fine-needle aspiration biopsy diagnosis: comparison of cytology and combined cytology and transmission electron microscopy with final histological diagnosis.

This report evaluates 74 fine-needle aspiration biopsies processed for transmission electron microscopy with subsequent surgical procedure. The specificity of diagnosis obtained by cytology alone was compared to that obtained by cytology and electro microscopy, using histologic diagnosis as the gold standard. When cytology gave a diagnosis of malignancy but could not give tumor category or type, electron microscopy could correctly give both. When cytology could give tumor category but not type, electron microscopy correctly identified type in the majority of cases. When cytology gave tumor category and type, electron microscopy confirmed the diagnosis. Transmission electron microscopy is very helpful when the cytopathologist can diagnose malignancy but cannot give tumor category and/or type. When the cytopathologist is specific in his/her diagnosis, TEM is not as helpful.

Fine needle aspiration biopsy diagnosis of a gastrointestinal stromal tumor utilizing transmission electron microscopy.

BACKGROUND: Gastrointestinal stromal tumors are spindle cell tumors with no specific cell lineage occurring in the gastrointestinal tract and cytologically resemble other benign and malignant spindle cell tumors. Distinctive ultrastructural features in some of these tumors have not been previously emphasized. CASE: A 76-year-old, white female presented with multiple tumor masses distributed in the large bowel. Fine needle aspiration biopsy demonstrated a cellular aspirate composed of spindle cells, some of which were loosely arrayed and some of which were in cohesive clusters. Many of the cells contained long cytoplasmic processes. Ultrastructurally the cells demonstrated long cytoplasmic processes upon which multiple shorter, fingerlike projections arose. Subsequent surgical resection confirmed the cytologic and ultrastructural findings. CONCLUSION: Electron microscopy has a role to play in the diagnosis of gastrointestinal stromal tumors.

Testicular juvenile capillary hemangioma: conservative management with frozen-section examination. A case report.

Juvenile capillary hemangioma, an exceptionally rare benign neoplasm, seen in an 18-year-old patient, was managed in an unorthodox fashion. The patient insisted on a conservative approach to the management of his tumour. In an effort to comply with his wishes, frozen-section examination of the tumour was carried out. The astute observations of the pathologist who recognized the juvenile capillary hemangioma made possible a conservative surgical excision and testicular repair. The case illustrates some of the difficulties that may be encountered in the successful management of testicular tumours.

Processing fine needle aspiration biopsies for electron microscopic examination. Experience implementing a procedure.

While processing needle rinses from fine needle aspiration biopsy material for electron microscopy, we experienced difficulties not fully outlined previously. Problems in preservation were traced to the time elapsed before glutaraldehyde was added to the needle rinse, which had been held in a physiologic transport medium; a tendency toward hypotonicity of the commercially prepared transport medium; and vigorous handling of the needle rinse. When these problems were dealt with, preservation improved dramatically. The problem of scanty material available for ultrastructural evaluation was dealt with by decreasing the number of smears made and filtering the needle rinse to capture tissue fragments. Implementation of the procedure required leadership, good communication, motivated cytotechnologists and cytopathologists, and continuous supervision and monitoring. In cases with adequately cellular well-preserved material available for electron microscopy, ultrastructural evaluation made a contribution of clinical value to the diagnosis in 48% of cases.

Fine-needle aspiration biopsies of metastatic neuroendocrine tumors in liver: use of transmission electron microscopy and protein A gold technique in diagnosis.

Five fine-needle aspiration biopsies of liver were studied to evaluate the use of electron microscopy and protein A gold technique in the diagnosis of metastatic neuroendocrine tumors. All five cases had cytologic features suggestive of neuroendocrine tumors and neurosecretory granules on ultrastructural examination. The aspirates were stained by the immunoperoxidase technique and the postembedding protein A gold technique using the antibody to chromogranin A. Three cases were positive for chromogranin A by both immunoperoxidase and protein A gold techniques. Two cases were positive by protein A gold technique and negative by immunoperoxidase technique. Confirmation of neurosecretory granules by immunochemistry is ideal, since ultrastructurally they can be mimicked by other electron-dense inclusions. Advantage of the protein A gold technique is the use of the same material for both ultrastructural evaluation and the protein A gold technique.

Inflammatory pseudotumor of the spleen. Morphological, radiological, immunophenotypic, and ultrastructural features.

A case of inflammatory pseudotumor of the spleen is described. Its rapid enlargement, demonstrable by ultrasound studies and computed tomographic scan, its gross appearance, and some of its histologic features suggested malignant lymphoma. However, a characteristic circumferential zonal pattern and polytypic immunophenotype helped to establish the correct diagnosis. In retrospect, the zonal pattern was also identified radiologically.

Angiosarcoma of the uterus: a case report.

We are reporting a case of angiosarcoma of the uterus in which the diagnosis was confirmed ultrastructurally by demonstration of Weibel-Palade bodies in the tumor cells. Only 10 cases of this entity have been previously documented in the literature.

Langerhans cell histiocytosis in monozygotic twins.

Langerhans cells histiocytosis, one of a group of histiocytosis syndromes characterized by Langerhans cell infiltration, has many clinical manifestations. In the past 30 years, numerous cases of presumed Letterer-Siwe disease, the acute multiorgan variant, have been reported in twins and siblings. Only recently has the Histiocyte Society established a criterion for a "definitive diagnosis" of Langerhans cell histiocytosis--the presence of Birbeck granules within the cells of the histiocytic infiltrate. We report the fatal outcome of Langerhans cell histiocytosis in monozygotic twin infants. There is no satisfactory explanation why Langerhans cell histiocytosis occurs concurrently in twins. We suggest that cytokines may provide an endogenous signal that triggers the pathologic proliferation of Langerhans cells.

Electron microscopy of chronic eosinophilic pneumonia.

We have investigated two cases of chronic eosinophilic pneumonia using the electron microscope. The alveolar septa were thickened due to edema and an infiltrate of numerous mononuclear cells and eosinophils, with a few lymphocytes and occasional plasma cells. Macrophages were often located close to eosinophils and extracellular eosinophilic granules. Occasional eosinophilic granules were observed in the cytoplasm of mononuclear cells. The most striking finding was the presence of distinctive elongated, narrow, tubular inclusions in the cytoplasm of several of the mononuclear cells. These inclusions presented complex curved profiles which sometimes terminated in small, dilated, dense vesicles. Some of the narrow tubular sections of the inclusions presented a pentalaminar structure. Elsewhere, the tubular structures showed localized globular dilatations which contained granular material. Elongated strands of electron-dense material, identical to that forming the intracytoplasmic inclusions, were also located extracellularly, between adjacent mononuclear cells and between mononuclear cells and eosinophils. These inclusions are considered to be the product of phagocytosis of cellular debris and to be related to phagolysosomes rather than to Birbeck granules.