Angioimmunoblastic lymphadenopathy with dysproteinemia. Immunohistologic and ultrastructural studies.

Immunoblasts of the B-cell line and immunoblasts of the T-cell line have very similar light-microscopic appearances but different immunologic compositions. The immunoblasts of a patient with angioimmunoblastic lymphadenopathy with dysproteinemia were found to bear surface immunoglobulin and complement receptor. They lacked receptor for cytophilic antibody. Surface villous projections were demonstrated by scanning electron microscopy. These features strongly indicate their B-cell origin.     

Testicular plasmacytoma. A case report with immunohistochemical studies and literature review

Plasmacytomas of the testes are extremely rare tumors, especially when occurring in the absence of a previous or concurrent diagnosis of multiple myeloma. We present a case of solitary testicular plasmacytoma in a 71-year-old man who had no clinical evidence of myeloma. Immunohistochemical stains showed monoclonal cytoplasmic production of IgA-kappa within tumor cells. A summary of the other reported cases of testicular plasmacytoma is presented. Plasmacytoma of the testes, while occasionally manifesting as a solitary, primary lesion, most likely is a precocious, highly unusual manifestation of systemic multiple myeloma.     

Chronic myelomonocytic leukemia: an ultrastructural study by transmission and scanning electron microscopy.

The hematologic findings in three cases of chronic myelomonocytic leukemia are presented, with results of ultrastructural studies by transmission and scanning electron microscopy on two of the cases. In the peripheral blood there was a dual, non-lymphocytic, markedly increased population of granulocytes and monocytes. The granulocytes showed marked nuclear abnormality and nuclear cytoplasmic organelle asynchrony. In the marrow the majority of the cells appeared granulocytic but atypical forms and intermediate difficult to distinguish from monocyte precursors were evident by electron microscopy. The ultrastructural findings lend some support to the concept that the neoplastic granulocytes and monocytes having a common precursor.     

Neurothekeoma. Report of a case with immunohistochemical and ultrastructural studies

A case of neurothekeoma in a 52-year-old woman is reported. The tumor developed on the medial aspect of the right nostril as a well-demarcated, dome-shaped, erythematous nodule of rubbery consistency. Microscopically, it consisted of numerous nests and cords of spindle-shaped cells in the dermis. Some of the tumor cell nests appeared epithelial-like, while the other areas showed a myxomatous appearence with various amount of mucinous matrix in the intercellular space. Neurothekeoma is a benign cutaneous tumor, and is considered to be of schwann cell origin. In the present case, the tumor cells did not stain positively for S-100 protein, despite the light microscopic suggestion of peripheral nerve origin. Ultrastructurally, most tumor cells contained a large number of myelinoid figures. This ultrastructural finding appears to be a useful diagnostic characteristics of neurothekeomas.     

Tropical myositis: ultrastructural studies.

Specimens of muscle were obtained from non-suppurating lesions of nine patients with tropical myositis. When examined in an electron microscope, these revealed patchy myocytolysis with loss of band structure. Perimysial cells were also degenerate. Sections from two out of nine patients revealed intracellular vesicles, about 80 nm in diameter, some of which contained 10 nm granules. These vesicles were seen budding from cell membranes and resembled virus particles. The focal necrosis with which they are associated and their absence from control sections support the concept that they are related to the disease process.     

Melanotic peritoneal cyst. Light-microscopic and ultrastructural studies

We describe a patient with a melanotic peritoneal cyst. The multilocular cyst was lined by heavily pigmented mesothelial cells. Scattered dendritic melanocytes were also seen underlying the mesothelium. By light and electron microscopy, the lesion appeared to imitate the pigmentation process of the skin. Special stains, to confirm the character of both mesothelial and dendritic cells (melanocytes), were also performed. The above findings constitute the first complete documentation of the relationship of melanocytes with mesothelial cells in humans. Thus, the possibility of primary melanosis peritonei, independent of melanogenic tumors of the ovary, is shown.     

Acute lymphoblastic leukemia, hand-mirror variant. A detailed ultrastructural study.

The hand-mirror cell in acute lymphoblastic leukemia may have important immunologic, pathogenic, and prognostic implications. To learn more about this cell, a detailed ultrastructural analysis was performed. Fifty electronmicrographs of lymphoblasts from an untreated patient with acute lymphoblastic leukemia with numerous hand-mirror cells in the bone marrow were compared with 60 electronmicrographs of lymphoblasts from six patients with classic acute lymphoblastic leukemia. The unique qualitative ultrastructural features of the hand-mirror cells were the presence of undamaged mitochondria and uropods (handles) with terminal microspikes containing circular organized arrangement of 50-A microfilaments. Quantitative differences between hand-mirror cells and lymphoblasts were observed in nuclear perimeters (P less than 0.0001), nuclear lengths (P less than 0.001), cytoplasmic lengths (P less than 0.0002), nuclear-cytoplasmic length ratios (P less than 0.0001), and numbers of mitochondria (P less than 0.002). These findings indicate that hand-mirror cells contain ultrastructural components that are related to cell motility and the immunologic process. These results are significant in that the hand-mirror cells may be associated with an immunologic mechanism that is involved in leukemogenesis.     

Ionescu-Shiley bovine pericardial bioprostheses. Histologic and ultrastructural studies.

Studies were done on the structural changes that develop in Ionescu-Shiley valves that are used as replacement heart valves for 4 to 8 years. These changes were compared with those found in similarly used porcine aortic valve (PAV) bioprostheses. A variety of morphologic differences were observed between bovine pericardial valve (BPV) and PAV bioprostheses after orthotopic implantation including: primary tissue failure associated with the use of an alignment suture, thickening of valve leaflet, leaflet tissue delamination, leaflet calcification, and dystrophic alterations of collagen. These findings indicate that valve design criteria directly influence the durability of pericardial valves. However, other factors unique to pericardial tissue also affect the durability and performance of BPVs. These factors include the inability of pericardial tissue to accommodate dynamic stresses; the extensive insudation of plasma proteins and lipids; and the inability to reduce leaflet calcification using agents that effectively mitigate calcification in PAV bioprostheses.     

The clear-cell variant of uterine epithelioid leiomyoma. An immunohistologic and ultrastructural study

A case of a rare uterine clear-cell epithelioid leiomyoma is presented, emphasizing immunohistologic and ultrastructural findings. The presence of actin, vimentin, desmin, muscle-specific antigen, and smooth-muscle-specific actin in tumor cells indicates a smooth-muscle origin, confirmed by electron microscopy. Numerous vacuolated mitochondria produced the cytoplasmic "clearing" on light microscopy.     

Malignant renal rhabdoid tumour. Immunohistochemical and ultrastructural studies

In an effort to establish their possible histogenesis, three cases of renal rhabdoid tumour and their metastases were studied both by a battery of polyclonal and monoclonal antibodies using the avidin-biotin-peroxidase complex technique and by electron microscopy. Vimentin was demonstrated in renal rhabdoid tumour in two cases and in all metastatic deposits. Cytokeratin (39, 43 and 50 kD) was not demonstrable in the three renal rhabdoid tumours, but was strongly positive in all metastatic lesions in one case. Epithelial membrane antigen was present in one renal rhabdoid tumour and in pulmonary metastases in two cases. Ultrastructural study showed epithelial differentiation in all tumours: basal lamina and convergent tight junctions were demonstrated; intracytoplasmic intermediate filaments were present in all primary and metastatic tumours. Rhabdoid tumours thus exhibited heterogeneous immunophenotypic expression suggesting that they are derived from mesenchymal cells which are capable of differentiating into epithelial cells.     

Immunological and ultrastructural studies in acute biphenotypic leukaemia.

AIMS--To compare the sensitivity of the ultrastructural method to detect myeloperoxidase (MPO) with light microscopy and immunocytochemistry using an anti-MPO antibody; to examine the expression of lymphoid antigens in relation to MPO activity in blast cells from cases of biphenotypic leukaemia. METHODS--Blast cells from 14 cases of biphenotypic acute leukaemia were analysed. Immunological markers were performed by single or double immunofluorescence staining on a flow cytometer. The presence of MPO was determined by light microscopy, electron microscopy on fixed and unfixed cells, and by immunoalkaline phosphatase with an anti-MPO antibody. The immunogold method was applied at the ultrastructural level to assess the expression of lymphoid and myeloid antigens at the same time as the MPO activity. RESULTS--Six of the 14 cases were initially classified as acute lymphoblastic leukaemia (ALL) and eight as acute myeloid leukaemia (AML). MPO activity was shown at the ultrastructural level in 4-99% blasts from all cases. Six of the 14 were MPO negative by light microscopy and three of these were negative with the antibody anti-MPO. Coexpression of lymphoid antigens (CD19, CD10, or CD2) and MPO was shown by the immunogold method in four out of 11 cases; in seven cases the blasts coexpressed myeloid antigens (CD13, CD33) and MPO. CONCLUSIONS--Electron microscopy is more sensitive for showing MPO than light microscopy and immunocytochemistry; the immunogold method combined with MPO used at the ultrastructural level can help to define the cell lineage involved in biphenotypic leukaemia by highlighting the myeloid component defined by MPO.     

Splenic lymphoma with circulating villous lymphocytes. Report of a case with immunologic and ultrastructural studies.

A case of splenic lymphoma with circulating villous lymphocytes is reported. Short surface cellular expansions were observed on blood and marrow films and by transmission electron microscopy. The immunophenotype was that of mature B cells without CD5, CD10, CD11c, or CD25 expression or tartrate-resistant acid phosphatase. Despite a basophilic plasmacytoid-like cytoplasm, this case of splenic lymphoma with circulating villous lymphocytes differed from splenic immunocytoma in that immunofluorescence and ultrastructure suggested that the neoplastic cells did not possess high levels of intracytoplasmic immunoglobulin. Treatment of cytopenia was best achieved by splenectomy and the total follow-up thus far (30 months) seems to indicate a case of low-grade malignant lymphoma.     

Collagenous spherulosis of the breast. Immunohistochemical and ultrastructural studies

Collagenous spherulosis of the breast is a recently described benign breast lesion that has previously been seen only incidentally. The authors report two cases of this lesion studied by immunohistochemistry and electron microscopy and a third case studied by light microscopy alone. The results demonstrate the participation of two cell types in the process: myoepithelial cells, which stained positively for cytokeratin, S-100 protein, and muscle-specific actin and contained intermediate filaments with dense bodies, pinocytotic vesicles, and formed cell junctions; and epithelial cells, which reacted for cytokeratin but not for S-100 protein or muscle-specific actin and contained intracytoplasmic lumina, formed lumina with microvilli, and desmosomes. Material constituting the spherules stained intensely for type IV collagen, and its ultrastructure was similar to that of basement-membrane material. The authors conclude that collagenous spherulosis results from a proliferation of epithelial and myoepithelial cells, the latter of which produce basement-membrane material.     

Pulmonary blastoma. Immunohistochemical and ultrastructural studies of a case

The immunohistochemical and ultrastructural features of a case of pulmonary blastoma in a 39-year-old woman are documented. Three types of cells were observed: epithelial, mesenchymal and 'blastomatous'. The latter stained with intermediate filament antibodies similar to those of mesenchymal and epithelial elements, thus supporting the hypothesis that this tumour is derived from a pluripotent undifferentiated element.     

Fibrosarcoma mimicking plasmacytoma or carcinoma: an ultrastructural study of 4 cases

Because the fibroblast has a remarkable capability of phenotypic modulations, reflected in both morphologic and immunohistochemical (IHC) changes, ultrastructural studiesare mandatory to identify the variants of fibroblasts. Myofibroblasts or histiofibroblasts are such examples, demonstrating chimeric ultrastructural features of fibroblastic cells in common with smooth muscle cells or with histiocytes, respectively. The presence of epithelioid fibroblastic cells sharing morphologic features with epithelial or plasma cells has not been yet characterized. The authors identified 4 cases of fibrosarcomas (FS) characterized by an unusual phenotype and associated with peculiar ultrastructural findings. The electron microscopic (EM) findings were correlated with the histologic appearance and immunoprofile. All tumors were located in the extremities, 3 in soft tissues and 1 in the bone. By light microscopy 2 cases were composed predominantly by round uniform cells with a striking plasmacytoid appearance. One case mimicked carcinoma, composed predominantly by epithelioid cells and scattered giant tumor cells. The fourth case showed a mixture of plasmacytoid-like and epithelioid cells. By IHC, tumor cells were positive for vimentin and in 2 cases also for epithelial membrane antigen. Kappa/lambda light chain and cytokeratins markers were negative. By EM all 4 tumors showed in addition to classic features of fibroblasts, unusual epithelial-type features, such as secretory granules of "neurosecretory-type" (3 cases), rudimentary cell junctions (3 cases), microvilli (2 cases), and lumen-like structures (1 case). One plasmacytoid-type tumor showed finely granular extracellular deposits. The study describe 4 examples of fibrosarcomas with unusual features at the ultrastructural level, which are associated microscopically with a peculiar phenotype, mimicking plasmacytoma or carcinoma. These findings broaden the spectrum of fibroblastic cell variants in neoplasia.