Congenital mesoblastic nephroma: report of a Case with review of the most significant literature.

AIMS AND BACKGROUND: Congenital mesoblastic nephroma (CMN) is a rare pediatric tumor of the kidney with the highest peak of incidence during the first 3 postnatal months. It has previously been confused with Wilms' tumor (which, on the contrary, is rare during the first six months of age and is still considered a histogenetic congener). CMN almost always has a favourable prognosis. Therefore, CMN needs to be correctly diagnosed and differentiated from other pediatric renal neoplasms. Two morphological subtypes are currently distinguished histologically: the classical or leiomyomatous type and the atypical or cellular type. Mixed forms with a combination of the two patterns are also on record. Recurrence and even tumor-related death have been described in the literature and always related to the atypical form or to the mixed form, particularly in patients aged more than 3 months and in those cases in which the surgical removal was not complete. Opinions concerning post-surgical clinical management, especially in regard to adjuvant therapy, are not unanimous. METHODS: A case of CMN, predominantly of the classical histological subtype diagnosed in a baby with a follow-up of 6 years, is herein presented. The tumor was discovered at birth and surgically removed after one month. Since the tumor showed a high mitotic index (one of the characteristics of the cellular subtype) and the perirenal fat was focally involved with the tumor, the possibility of giving adjuvant chemotherapy was considered. Flow cytometric analysis was also performed which showed a diploid DNA content of neoplastic cells. RESULTS: The tumor was completely removed, surgical margins were free histologically, and no clear-cut histological features of the atypical subtype were noted. Flow cytometrically, it showed the euploid DNA content. Consequently no additional therapy was given. Six years after surgery the patient is developing well and is free of disease. He has regular follow-up examinations. CONCLUSIONS: CMN almost always pursues a benign clinical course if diagnosed under three months of age and if totally surgically excised independent of histological type. Criteria for management of atypical cases are not unanimous in regard to the benefit of additional therapy after surgery.

[Pigmented fibrosarcomatous dermatofibrosarcoma protuberans (Bednar tumor). 3 case reports, analogy with the "conventional" type and review of the literature]. / Il dermatofibrosarcoma protuberans "pigmentato" (tumore di Bednar) fibrosarcomatoso. Osservazione di tre casi, analogie con la forma "convenzionale" e revisione della letteratura.

BACKGROUND: The so-called Bednar tumor represents a pigmented variant of dermatofibrosarcoma protuberans (DFSP) and is characterized by a usually scant (1-5% of cells) population of dendritic melanocytes within an otherwise typical DFSP. This pigmented variant accounts for up to 5% of all DFSPs. Other variants of DFSP include cases showing features (in the primary or recurrence) of either giant cell fibroblastoma or fibrosarcoma. Less than 5% of DFSPs are associated with metastases and many of these show either a fibrosarcomatous component or, much more rarely, an "MFH"-like appearance. Only one previous case has been reported which showed combined features of the pigmented and fibrosarcomatous variants. MATERIALS: We present herein 3 cases of fibrosarcomatous Bednar tumor, all occurring in males, 2 aged 75 and 1 aged 23; two patients were white and one black. The tumors were located on the trunk or shoulder and two had been present for many years with recent rapid growth. One patient developed local recurrence and metastases to bone and lung and died within 1 year. The other two patients are disease free at 3 and 5 years follow-up respectively. All three cases showed typical histological features and in two tumors the pigment was evident macroscopically. CONCLUSIONS: A through literature review, including all cases of fibrosarcomatous DFSP and metastasizing fibrosarcomatous DFSP (whether or not pigmented), confirms that the fibrosarcomatous variant of DFSP (including its pigmented counterpart) is significantly more aggressive than usual DFSP, thus underlining the importance of its accurate recognition.

["Hyaline-cell chondroid syringoma." Morphological, immunohistochemical and ultrastructural study of a case and review of the literature]. / "Siringoma condroide a cellule ialine." Studio morfologico, immunoistochimico e ultrastrutturale di un caso e revisione della letteratura.

Chondroid syringoma represents the cutaneous counterpart of mixed tumor ("pleomorphic adenoma") of salivary glands, therefore it is also termed mixed tumor of the skin. The presence of hyaline cells in mixed tumors of salivary gland is a very well known event. Tumors mainly or exclusively composed of hyaline cells are termed myoepitheliomas of hyaline type, accordingly to their alleged myoepithelial origin. Scanty components of hyaline cells in chondroid syringomas of the skin have also been observed since more than a decade. However chondroid syringomas mainly or exclusively composed of hyaline cells have been reported only very recently. If the hyaline cells of chondroid syringomas are myoepithelial or epithelial in origin is still a matter of debate, we prefer to retain the descriptive label "hyaline cell-rich chondroid syringoma" as originally conceived by JA Ferrero and AG Nascimento the patronimic authors of the entity. A case of hyaline cell-rich chondroid syringoma is reported on in a white male patient aged 64, which occurred on the external ear of 1-year duration. This case was studied immunohistochemically and ultrastructurally. Both immunoprofile which included reactivity for vimentin, low molecular weight cytokeratins, S-100 protein, GFAP (focally), alfa-smooth actin and muscle-specific actin, and ultrastructural features including evidence of intermediate filaments (non-bundling filaments, tonofilaments), desmosomes, and thin filaments of actin type sustain a myoepithelial differentiation for hyaline cells of this tumor and site. The authors also remark the importance of being aware of this new entity during the diagnostic practice for avoiding misinterpretation. A list of condition to be taken into account in differential diagnosis is also given.

[Techniques for the diagnosis of kidney diseases. Is there a role for the immunoperoxidase method in the evaluation of immunologic glomerulopathy on biopsy specimens, including those in paraffin? Our experience: preliminary results]. / Tecniche di diagnostica nella patologia renale. Esiste un ruolo per la metodica di immunoperossidasi nella valutazione delle glomerulopatie immunologiche su biopsie incluse in paraffina? La nostra esperienza: primi risultati.

Firstly an extensive summary of the diagnostic power and limits in renal glomerular pathology of light microscopy even corroborated by all the special histochemical stains is made. Secondly a complete list of all those renal glomerular diseases in which electron microscopy is unanimously considered necessary for the diagnosis is given as well as the main and most updated references pertinent to those rare and recently recognized pathological entities in which EM proved as a fundamental diagnostic tool are provided. Thirdly the authors focus on the importance of immunohistochemistry (IIC) in the diagnosis of immune-mediated renal glomerular diseases. The advantages and disadvantages of immunofluorescence microscopy (IF) and immunoperoxidase method (I-perox) are respectively discussed. The value of I-perox staining method applied to sections from paraffin blocks is emphasized and some technical suggestions in order to optimize results are given. Among the latter the choice of the used fixative for the purpose of preserving antigenicity of immunoglobulins and complement fractions, the timing of tissue fixation as well as the quantitation of enzymatic pretreatment relative to the duration of fixation, and the repeated washings with phosphate-buffer saline to minimize background staining. Ultimately the authors report on their preliminary personal results with the use of I-perox staining on sections from paraffin embedded renal core biopsies. Although if is their favourite diagnostic microscopy for evaluating renal immunopathology the authors underline I-perox method as a helpful tool to rely on at least in those circumstances when frozen material for IF is not available due to the scarcity of core biopsy, when glomeruli are absent in frozen sections, or when due to a technical lab accident the frozen tissue devoted to IF has been ruined or lost, and the only available material is the one which lies embedded in paraffin. The LSAB ("labelled streptavidin biotin") complex and PAP ("peroxidase-antiperoxidase") working procedures are provided in detail.

[Primary angiosarcoma of the thyroid. Presentation of a case (epithelioid type) and nosological problems]. / L'angiosarcoma primitivo della tiroide. Presentazione di un caso (varietà "epitelioidea") e promlematiche nosologiche.

There is a great deal of confusion in the literature as to whether or not true angiosarcomas of the thyroid exist or whether these are all anaplastic carcinomas of the thyroid which have an angiosarcomatoid appearance. Due to the fact that undifferentiated carcinomas of this organ can strikingly resemble various sarcomas it is recommended that great care should be taken prior to qualify as an angiosarcoma a malignant thyroid tumor. A lot of viewpoints have been expressed so far in literature concerning this theme, and they can be summarized as follows. On one side and not admitting the existence of angiosarcoma in this location there are opinions which think of it as a "variant" of undifferentiated carcinoma (a pure carcinoma with a pseudovascular pattern or a carcinoma with an intermingled non-neoplastic reactive vascular component), or as a neoplasm in transition from epithelial to endothelial differentiation ("mesenchymal neometaplasia"), or as a carcinoma with aberrant expression of endothelial markers, or as a carcinoma with a non-specific uptake of endothelial antigens(e.g. from serum in case of F-VIII R-Ag positivity). On the other side there are opinions in favor of the existence of such an entity, based upon light microscopy features coupled with immunocytochemical results (endothelial antigens expression without or with cytokeratins expression) and with the possible support of electron microscopy. Anyway ultrastructural findings of specific markers (Weibel-Palade bodies, pericellular basal lamina, tight junctions, subplasmalemmal pinocytotic vesicles) according to some authors are not a prerequisite: so poorly differentiated neoplasma can fail to show those histogenetic markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Invertase activity of intact cells of Saccharomyces cerevisiae growing on sugarcane molasses. II. Unsteady-state continuous-culture tests.

During unsteady-state continuous culture of Saccharomyces cerevisiae on sugarcane blackstrap molasses, the invertase activity of the intact yeast cells oscillated. Disturbances were produced by changing medium composition, air rate, impeller speed, and dilution rate. The influence of the oxygen supply rate and of the dilution rate on the invertase activity depend on the medium composition. The highest invertase activity was obtained when, after a steady-state attained using unsupplemented culture medium, nutrients were added to the feeding mash. A Monod-like equation seems to be the best representation of the correlation between the specific rate of reducing sugars consumption and the specific rate of nonreducing sugar hydrolysis by the yeast cells.

Invertase activity of intact cells of Saccharomyces cerevisiae growing on sugar cane molasses. I. Steady-state continuous culture tests.

During the steady-state continuous culture of Saccharomyces cerevisiae on sugar cane blackstrap molasses under different experimental conditions, oscillatory variations of the invertase activity of the intact yeast cells were observed. The continuous morphological changes of the cells wall and of the periplasmic space affecting the interaction between invertase and sucrose molecules could be responsible by the observed oscillatory phenomena. The average invertase activity at the steady state is linearly correlated to the cell's growth rate.

Some observations on oscillatory changes in the growth rate of Saccharomyces cerevisiae in aerobic continuous undisturbed culture.

Oscillatory changes in the growth rate were observed in undisturbed continuous culture of Saccharomyces cerevisiae on sugar-cane molasses media when nitrogen sources (2.56 to 6.17 g/liter of ammonium sulfate or 1.22 g/liter of urea) were added to the feeding mash and when the air rate was 1.3 to 1.6 v/v/m. The oscillations were not affected by the addition of yeast extract. The suppression of the nitrogen source during the continous test leads to a nonoscillatory transient state. No oscillations occured at all when no nitrogen source was added to the medium and/or the air rate was equal to zero or equal to about 3.3 v/v/m. The oscillatory responses of the system were affected by a previous anaerobic continuous cultivation of the yeast.