Ultrastructural and immunohistochemical characterization of the so-called giant multinucleate cells in cutaneous collagenomas.

AIMS: This study was undertaken to compare the histopathological, immunohistochemical and ultrastructural features of the so-called giant multi nucleate cells in cutaneous collagenomas: giant-cell collagenoma and solitary sclerotic fibroma. METHODS AND RESULTS: We studied four collagenomas: one giant-cell collagenoma and three solitary sclerotic fibromas. All the cases showed an indolent clinical presentation and were histologically constituted by a well-demarcated dome-shaped proliferation of coarse collagen bundles with a varying number of interspersed giant multinucleate cells and stellate mononuclear cells. The immunohistochemical study on paraffin sections revealed that neoplastic cells in both collagenomas were vimentin and CD34-positive, whereas FXIIIa was only expressed in solitary sclerotic fibromas. In regard to the so-called giant multinucleate cells, we have ultrastructurally found that these cells were 'real' multinucleate cells in giant-cell collagenoma, whereas in solitary sclerotic fibromas they consisted of closely packed aggregates of individual stellate mononuclear cells. Moreover, perinuclear cisternae focally containing finely textured material of moderate density were unexpectedly found in giant cells of giant-cell collagenoma, a finding which was not observed in solitary sclerotic fibromas. Additionally, a characteristic cell-cell interaction between tumour cells and mast cells was encountered in all collagenomas. CONCLUSIONS: This study supports a distinctive immunohistochemical and overall ultrastructural profile of giant multinucleate cells in giant-cell collagenoma and solitary sclerotic fibroma, which suggests a different pattern of differentiation for these two related cutaneous lesions.

Psammomatous malignant melanoma arising in an intradermal naevus.

AIMS: A wide variety of differentiation patterns may be found in malignant melanoma. Schwannian features are unusual, and mostly present in the desmoplastic variant. We report the first description of psammoma bodies in malignant melanoma. METHODS AND RESULTS: A malignant melanoma arose in an intradermal naevus of the scalp in a 51-year-old woman, displaying focal neural-like features in the form of rosette-like pseudo-meissnerian alveolar nests, as well as numerous psammoma bodies grouped in a few areas. Tumour cell immunostaining for S100, HMB45, NKI-C3, and vimentin was detected. In addition, both malignant and benign melanocytic cells showed widespread MART-1 immunoreactivity. Differential diagnosis with psammomatous melanotic schwannoma, a feature of Carney's complex, is particularly emphasized, since dermal variants of this nerve sheath neoplasm have been described. In addition, its potential relationship with cutaneous malignant melanotic neurocristic tumour is discussed. CONCLUSIONS: This is, to our knowledge, the first reported case of cutaneous malignant melanoma with psammoma bodies.

[Adipose retroperitoneal tumors. Apropos a giant myxoid liposarcoma]. / Tumores adiposos retroperitoneales. A propósito de un liposarcoma mixoide gigante.

Liposarcomas are the most frequent retroperitoneal tumours, second only to lymphomas. We present a new case of giant retroperitoneal liposarcoma treated in our hospital. A discussion is presented on the most peculiar aspects of this tumour, such us: multicentricity, tendency to local relapse, and need to post-operative (adjuvant) radiotherapy. A review of all nationwide cases over the last few years is included.

[Cystic pyeloureteritis. A review of the literature in the period of 1946-1994 and a report of a new case]. / Pieloureteritis quística. Revisión de la literatura, periodo 1946-1994 y presentación de un nuevo caso.

Presentation of a new case of unilateral cystic pyeloureteritis in a 46-year old female patient. The condition presented as a right renoureteral colic. A revision is made of the 69 national cases published on such an uncommon condition, of obscure etiologic, pathogenic and therapeutical features. The accent is placed on its most significant aspects, such as: difficulties of differential diagnosis with other repletion defect imagen in the excretory tract and their frequent association to other diseases.

Immunocytochemical typification of mesothelial cells in effusions: in vivo and in vitro models.

We have performed immunocytochemical, immunoelectron microscopy, Western blot, and culture techniques using monoclonal antibodies against cytokeratin, vimentin, and desmin on 17 benign and 20 malignant effusions of pleural and ascitic origin. Triple coexpression of these three antigens was observed in benign reactive mesothelial cells as well as in one case of mesothelioma. All metastatic adenocarcinoma cells were consistently negative to desmin and positive to cytokeratin and vimentin. Present results were helpful to distinguish reactive and malignant mesothelioma from metastatic carcinoma cells in effusions.

Scanning electron microscopic evidence for neural differentiation in Ewing's sarcoma cell lines.

A number of recent studies have suggested a relationship between Ewing's sarcoma (ES) and other small round cell tumours of childhood such as peripheral neuroepithelioma (PN). We report scanning electron microscopic studies on the character of induced neural differentiation in ES, neuroblastoma, PN, osteosarcoma and colon carcinoma. We found evidence of neural differentiation in both neural lines and in one of two Ewing's lines before treatment. After differentiation, both Ewing's and neural lines developed neuritic processes with varicosities and little arborization, except for the initially undifferentiated Ewing's line (A4573) which displayed extensive lateral sprouting from neuritic processes after differentiation. Neither treated nor untreated osteosarcoma or colon carcinoma displayed any evidence of neural differentiation. Further, neuroblastoma cells are easily distinguished from ES and PN by virtue of their single, unbranched neurites and lack of lateral sprouting or filopodia. These results provide further evidence for the neural character and close relationship between ES and PN.