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Context: The effect of a lifestyle intervention to reduce liver fat content in nonalcoholic fatty liver disease in humans is influenced by genetics. We hypothesized that the amino acid exchange in human Gly388Arg (mouse homolog: Gly385Arg) in fibroblast growth factor receptor 4 (FGFR4), which regulates bile acid, lipid, and glucose metabolism, could determine hepatic lipid accumulation and insulin sensitivity. Mechanisms of this substitution were studied in mice under normal chow and high-fat diets.Design: In humans, the Gly388Arg polymorphism was studied for its relationship with changes in liver fat content and insulin sensitivity during 9 months of a lifestyle intervention. We also studied a knock-in mouse strain with an Arg385 allele introduced into the murine FGFR4 gene under normal chow and high-fat diets.Results: In humans, the FGFR4 Arg388 allele was not associated with liver fat content or insulin sensitivity in subjects who were overweight and obese before lifestyle intervention. However, it was associated with less decrease in liver fat content and less increase in insulin sensitivity during the intervention. In mice receiving normal chow, the FGFR4 Arg385 allele was associated with elevated hepatic triglyceride content, altered hepatic lipid composition, and increased hepatic expression of genes inducing de novo lipogenesis and glycolysis. Body fat mass and distribution, glucose tolerance, and insulin sensitivity were unaltered. The FGFR4 Arg385 allele had no effect on glucose or lipid metabolism under the high-fat diet.Conclusion: Our data indicate that the FGFR4 Arg388(385) allele affects hepatic lipid and glucose metabolism specifically during healthy caloric intake.

OBJECTIVE The nitric oxide/cGMP/cGMP-dependent protein kinase type I (cGKI) signaling pathway regulates cell functions that play a pivotal role in the pathogenesis of type 2 diabetes. However, the impact of a dysfunction of this pathway for glucose metabolism in vivo is unknown. RESEARCH DESIGN AND METHODS The expression of cGKI in tissues relevant to insulin action was analyzed by immunohistochemistry. The metabolic consequences of a genetic deletion of cGKI were studied in mice that express cGKI selectively in smooth muscle but not in other cell types (cGKI-SM mice). RESULTS In wild-type mice, cGKI protein was detected in hepatic stellate cells, but not in hepatocytes, skeletal muscle, fat cells, or pancreatic β-cells. Compared with control animals, cGKI-SM mice had higher energy expenditure in the light phase associated with lower body weight and fat mass and increased insulin sensitivity. Mutant mice also showed higher fasting glucose levels, whereas insulin levels and intraperitoneal glucose tolerance test results were similar to those in control animals. Interleukin (IL)-6 signaling was strongly activated in the liver of cGKI-SM mice as demonstrated by increased levels of IL-6, phospho-signal transducer and activator of transcription 3 (Tyr 705), suppressor of cytokine signaling-3, and serum amyloid A2. Insulin-stimulated tyrosine phosphorylation of the insulin receptor in the liver was impaired in cGKI-SM mice. The fraction of Mac-2–positive macrophages in the liver was significantly higher in cGKI-SM mice than in control mice. In contrast with cGKI-SM mice, conditional knockout mice lacking cGKI only in the nervous system were normal with respect to body weight, energy expenditure, fasting glucose, IL-6, and insulin action in the liver. CONCLUSIONS Genetic deletion of cGKI in non-neuronal cells results in a complex metabolic phenotype, including liver inflammation and fasting hyperglycemia. Loss of cGKI in hepatic stellate cells may affect liver metabolism via a paracrine mechanism that involves enhanced macrophage infiltration and IL-6 signaling.

Posttransplantation lymphoproliferative disorder (PTLD) of the iris is a rare entity with only ten cases having been published as yet. Its clinical aspect is typical. Therapy is multimodal and affords an interdisciplinary approach. A 7-year-old boy developed a lymphoproliferative mass of the iris with uveitis 4 years after heart transplantation and immunosuppression. A progressive, flesh-colored thickening of the iris with secondary angle closure glaucoma necessitated a diagnostic and therapeutic iridectomy. Morphological investigation of the iris specimen disclosed a polymorphic posttransplantation lymphoproliferative disorder (PTLD) and the presence of Epstein-Barr virus (EBV) within the tissue. The EBV load in peripheral blood monocytes was massively elevated, thus indicating a chronic EBV infection. After conservative treatment and radiation therapy, the iris mass quickly resolved. There was no evidence of systemic PTLD. PTLD is a well-known, EBV-induced entity that rarely affects the eye. EBV is principally detectable in specimens of iris PTLD. If conservative, antiviral treatment fails, the iris lesions can be treated by local radiation therapy with very good success. In the near future, patients with PTLD of the eye may benefit from immunologic treatment with ex vivo generation of virus-specific T-lymphocytes.

Efficient engulfment of the intact cell corpse is a critical end point of apoptosis, required to prevent secondary necrosis and inflammation. The presentation of “eat-me” signals on the dying cell is an important part of this process of recognition and engulfment by professional phagocytes. Here, we present evidence that apoptotic cells secrete chemotactic factor(s) that stimulate the attraction of monocytic cells and primary macrophages. The activation of caspase-3 in the apoptotic cell was found to be required for the release of this chemotactic factor(s). The putative chemoattractant was identified as the phospholipid, lysophosphatidylcholine. Further analysis showed that lysophosphatidylcholine was released from apoptotic cells due to the caspase-3 mediated activation of the calcium-independent phospholipase A2. These data suggest that in addition to eat-me signals, apoptotic cells display attraction signals to ensure the efficient removal of apoptotic cells and prevent postapoptotic necrosis.

Background—Although numerous antibodies suitable for use on paraffin wax embedded sections are available for the subtyping of acute leukaemia (acute myelogenous leukaemia (AML) and acute lymphoblastic leukaemia (ALL)) in bone marrow biopsy sections, unequivocal identification of the cell line involved is sometimes impossible. Methods—Forty eight formalin fixed, paraffin wax embedded bone marrow biopsy specimens that had been decalcified in EDTA were investigated, including 42 thought to exhibit ALL on the basis of bone marrow smears. Five specimens exhibited AML and one biphenotypic leukaemia, as diagnosed immunohistochemically in bone marrow biopsies. Immunostaining was performed with antibodies against relatively specific B and T cell antigens. The blasts were investigated for rearrangements of the immunoglobulin heavy chain (IgH) and the T cell antigen receptor (TCR) genes. Results—Amplifiable DNA was obtained from all 48 specimens. An IgH gene rearrangement was detected in 20 of 23 c-ALL specimens. Four of seven T cell ALL (T-ALL) specimens had a TCR-γ gene rearrangement, and the one B cell ALL (B-ALL) specimen exhibited a clonal IgH gene. Three of four cases of unclassifiable ALL could be assigned to the B cell lineage on the basis of gene rearrangement analysis. Seven cases originally diagnosed in smears as ALL were rediagnosed as AML (n = 5) or biphenotypic leukaemia (n = 2) because of immunohistochemical reactivity for myeloperoxidase or lysozyme. Two of these AML cases and two of three cases of biphenotypic leukaemia exhibited a monoclonal IgH gene rearrangement. Conclusions—Acute leukaemia can be subtyped in bone marrow sections with a limited panel of antibodies suitable for use on paraffin wax embedded sections (against CD3, CD10, CD20, CD79a, myeloperoxidase, and lysozyme). In patients with ALL and a diagnostically equivocal immunophenotype, gene rearrangement analysis might indicate whether the B or T cell lineage is involved.

BACKGROUND: Slight, diffuse or focal lymphocyte proliferation is relatively common in bone marrow biopsy specimens. It may be impossible to determine whether this represents a reactive lymphocytosis or low grade non-Hodgkin lymphoma (NHL) on the basis of routine investigations alone. AIM: To investigate the supplementary use of molecular biological techniques in this situation. METHODS: 529 formalin fixed, paraffin embedded bone marrow biopsy specimens from the iliac crest were subjected to histological and immunohistochemical staining to determine the number and nature of the lymphocytes present. The cases were divided into three groups according to the lymphocyte count: normal (< 10% of nucleated bone marrow cells), slightly increased (10-30%), and markedly increased (> 30%). All of the last group could be diagnosed as NHL from the morphological findings alone. The clonality of rearrangements of the IgH and TCR gamma genes was investigated by polymerase chain reaction (PCR). RESULTS: Monoclonality was observed in 7.5% of the 372 cases with a normal lymphocyte count, in 50% of the cases with a modest increase in lymphocyte numbers (suggesting a diagnosis of low grade NHL not detected by immunostaining), and in 77% of the cases with markedly increased lymphocyte numbers. CONCLUSIONS: If PCR is used in addition to the immunohistochemical investigation of bone marrow biopsies, considerably more cases of NHL can be identified, making this of particular use in staging and detection of recurrences.

Background and Methods: Because the use of immunohistochemistry in the diagnosis of granulosa cell tumor (GCT) has not been fully explored, routinely processed (formalin-fixed, paraffin-embedded) tissue from 11 GCT, adult type, was investigated immunohistochemically (ABC method) with a broad spectrum of antibodies against various markers, including p53 and Ki-67. All of the tumors exhibited typical morphology, were limited to the ovary (stage I), and 7 cases followed a benign clinical course. Results: All the tumors exhibited strong expression of vimentin, but most other antigens (including smooth muscle actin) were expressed infrequently by a minority of tumor cells or not at all. Tumor cells in 9 GCT expressed inhibin A. All the tumors exhibited very low proliferative activity, fewer than 10% of the tumor cell nuclei being stained by the antibody MIB-1 (Ki-67 antigen). The antibody D07 revealed marked overexpression of p53 protein in only one tumor. Clinical outcome was not found to be related to immunophenotypic differences. Conclusions: The diagnosis of GCT should be based primarily on the typical morphology revealed by conventional stains, but additional immunohistochemical staining with a small panel of selected antibodies (for example, against keratin, vimentin, and inhibin A) may be helpful in a few cases. The very low proliferative activity and the lack of overexpression of p53 protein are consistent with the benign clinical behavior of the majority of GCT.

Objective: To determine whether the unusually high number of CD56+ large granular lymphocytes (LGL) in the decidua of early human pregnancy arises from selective migration or in situ proliferation. Design: Controlled clinical study. Setting: Academic research environment. Patient(s): Thirty healthy women undergoing therapeutic abortion of an intact pregnancy at 5–11 weeks' gestation. Intervention(s): Decidua was obtained by suction curettage; tissue and isolated cells were subjected to immunohistochemical and flow cytometric investigation. Main Outcome Measure(s): Proliferation rate of LGL. Result(s): The proportion of CD56+ cells positive for the proliferation-associated Ki-67 antigen was found to be 7%–23.5% by three different methods of investigation. These findings are consistent with those of flow cytometric analysis of the nuclear phase, which revealed 6%–22% of the LGL nuclei to be in the phases S+G 2 +M. Conclusion(s): The various methods of investigation revealed marked proliferative activity in the LGL of early pregnancy decidua. This finding suggests that in situ proliferation may be responsible for the high density of these cells in the decidua.

Due to similar clinical and neuroradiological features, intracranial inflammatory tumors (IITs) are frequently misdiagnosed as brain neoplasms, from which they notably differ in respect to therapy and prognosis. In this article, five cases of such tumors are presented. Three of the patients with brain tumors (cases 3, 4 and 5) presented a history of 'pararheumatic' syndromes but no diagnosis of defined immunopathies. On the basis of radiological findings, all processes were classified as genuine brain neoplasms, but histology showed reactive inflammatory features. The possible etiologies of these 'tumors' are discussed on the basis of all clinical and histological data of the patients. The spectrum of diseases potentially leading to the manifestation of an IIT is reviewed. Additionally, the presentation of case 5, who developed a highly malignant B-cell-lymphoma 6 months after the removal of an IIT without any histological signs of atypia, shows that this differential diagnosis always has to be kept in mind.

Summary Matrix metalloproteinases (MMPs) secreted by human cytotrophoblast cells are crucial for the invasion of the placental bed by these cells. The invasive growth of the trophoblast is similar to that of malignant tumors in many respects, but, unlike the latter, it is strictly controlled. Tissue inhibitors of metalloproteinases (TIMPs) have been postulated to play a role in the control of trophoblast invasion. In this immunohistochemical study, the distribution of TIMP-2 at the feto-maternal interface in first trimester human pregnancy was investigated. In the decidua, staining for TIMP-2 was found in stromal cells and the walls of blood vessels in all five specimens, but decidual leukocytes were nonreactive and staining of the endometrial epithelium was found in only two specimens. In the placenta, TIMP-2 immunoreactivity was found mainly in cytotrophoblasts, the strongest staining being observed in cytotrophoblast columns. The results suggest that TIMP-2 produced by certain cell populations in the decidua could play a role in regulating trophoblast invasion. As it is the first trimester cytotrophoblast columns that invade the placental bed, the strongest immunoreactivity for TIMP-2 in the placenta is found in cells that are known to produce MMPs and exhibit an invasive growth pattern. These findings indicate that TIMP-2 may also be involved in autoregulation of the invasive growth of the trophoblast.

The DNA ploidy pattern of nine hepatoblastomas and three normal liver specimens was investigated by flow cytometry. Areas of unlike differentiation in the same tumor were investigated separately. Normal liver tissue and the fetal subtype were always diploid. Aneuploidy was found in the embryonal subtype. The one case of small cell tumor was also diploid. When the fetal and embryonal areas of the same tumor were analyzed together, there was always an aneuploid peak in the histogram. There are obvious differences in DNA ploidy among the various hepatoblastoma subtypes. Differences in methods used, including the failure in some studies to evaluate areas of unlike differentiation in the same tumor separately, probably account to some extent for the conflicting results of previously reported studies. When flow cytometric analysis of the DNA content of a hepatoblastoma is performed, it is important to ensure that the various types of differentiation in the tumor are represented adequately in the material investigated, especially when conclusions about the prognosis are to be based on these findings.

We report the case of a 76-year old patient with third relapse of AML who was successfully treated with Imatinib. The decision to try Imatinib was guided by bright expression of c-kit on the patient's blasts. Treatment was well tolerated but the dose was reduced for pancytopenia and later stopped completely because of pneumonia. The patient recovered with i.v. antibiotics, antimycotics and s.c. G-CSF. Reevaluation of the bone marrow after the end of treatment demonstrated the absence of malignant blasts. Treatment with Imatinib was started again with the intention to prolong remission duration. During the following months peripheral blood counts stabilized in the normal range indicating that a fourth complete remission has been achieved in this patient. This is the first report demonstrating that Imatinib can induce complete remission in relapsed c-kit positive AML in an elderly patient. Prolonged cytopenia remains a considerable problem indicating that normal haematopoiesis is not completely independent of the signalling cascades inhibited by Imatinib. Nevertheless our report supports further study of this drug in c-kit positive AML.

Lifestyle intervention with diet modification and increase in physical activity is effective for reducing hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD). However, for a similar weight loss, there is a large variability in the change in liver fat. We hypothesised that cardiorespiratory fitness may predict the response to the intervention.Longitudinal study with increase in physical activity and diet modification.University teaching hospital.50 adults with NAFLD and 120 controls at risk for metabolic diseases.Total-, subcutaneous abdominal- and visceral adipose tissue by magnetic resonance tomography, liver fat by 1HMR spectroscopy and cardiorespiratory fitness (VO(2,max)) by a maximal cycle exercise test at baseline and after 9 months of follow-up.In all subjects total-, subcutaneous abdominal- and visceral adipose tissue decreased and fitness increased (all p0.0001) during the intervention. The most pronounced changes were found for liver fat (-31%, p0.0001). Among the parameters predicting the change in liver fat, fitness at baseline emerged as the strongest factor, independently of total- and visceral adipose tissue as well as exercise intensity (p = 0.005). In the group of subjects with NAFLD at baseline, a resolution of NAFLD was found in 20 individuals. For 1 standard deviation increase in VO(2,max) at baseline the odds ratio for resolution of NAFLD was 2.79 (95% confidence interval, 1.43-6.33).Cardiorespiratory fitness, independently of total adiposity, body fat distribution and exercise intensity, determines liver fat content in humans, suggesting that fitness and liver fat are causally related to each other. Moreover, measurement of fitness at baseline predicts the effectiveness of a lifestyle intervention in reducing hepatic steatosis in patients with NAFLD.

We sought to evaluate the relationship between parameters of bipolar radiofrequency (RF) ablation using internally cooled electrodes.Bipolar RF ablations (n = 24) were performed in ex vivo bovine liver using an internally cooled applicator with 2 electrodes located on the same shaft. The power-output was systematically varied (20-75 W). On the basis of our experimental data, mathematical functions were fitted and the goodness-of-fit was assessed by the parameter R.The duration to induce an increase of tissue resistance and the amount of applied energy increased with a decreased power-output. The maximum short-axis was 4.5 cm (20 W) and required an application of 64 kilojoules (kJ). The volume of coagulation can be determined as a function of the duration of energy application (R = 0.954) and the amount of applied energy (R = 0.945).The amount of applied energy and the duration of energy application can predict the volume of induced coagulation and may be useful to control internally cooled bipolar RF ablation.

Human parvovirus B 19 is known as a virus causing erythema infectiosum, arthropathy, transient aplastic crisis and intrauterine fetal death. Healthy hosts are able to clear the virus within weeks after infection. There are a few reports available in the literature regarding immunocompromised renal transplant recipients with persistent infection without seroconversion. Herein, we describe a 56-year old woman with a relapse of grade II follicular lymphoma who received a combined immunochemotherapy of rituximab, fludarabine and cyclophosphamide and subsequently developed a persistent parvovirus B19 infection. In the absence of serum immunoglobulin antibodies, PCR analysis of peripheral blood and bone marrow aspirate were positive for parvovirus B19. Treatment with IVIG treatment resulted in normalization of peripheral blood counts within 7 weeks.

OBJECTIVE—The α2-Heremans-Schmid glycoprotein (AHSG; fetuin-A in animals) impairs insulin signaling in vitro and in rodents. Whether AHSG is associated with insulin resistance in humans is under investigation. In an animal model of diet-induced obesity that is commonly associated with hepatic steatosis, an increase in Ahsg mRNA expression was observed in the liver. Therefore, we hypothesized that the AHSG plasma protein, which is exclusively secreted by the liver in humans, may not only be associated with insulin resistance but also with fat accumulation in the liver. RESEARCH DESIGN AND METHODS—Data from 106 healthy Caucasians without type 2 diabetes were included in cross-sectional analyses. A subgroup of 47 individuals had data from a longitudinal study. Insulin sensitivity was measured by a euglycemic-hyperinsulinemic clamp, and liver fat was determined by 1H magnetic resonance spectroscopy. RESULTS—AHSG plasma levels, adjusted for age, sex, and percentage of body fat, were higher in subjects with impaired glucose tolerance compared with subjects with normal glucose tolerance (P = 0.006). AHSG plasma levels were negatively associated with insulin sensitivity (r = −0.22, P = 0.03) in cross-sectional analyses. Moreover, they were positively associated with liver fat (r = 0.27, P = 0.01). In longitudinal analyses, under weight loss, a decrease in liver fat was accompanied by a decrease in AHSG plasma concentrations. Furthermore, high AHSG levels at baseline predicted less increase in insulin sensitivity (P = 0.02). CONCLUSIONS—We found that high AHSG plasma levels are associated with insulin resistance in humans. Moreover, AHSG plasma levels are elevated in subjects with fat accumulation in the liver. This is consistent with a potential role of AHSG as a link between fatty liver and insulin resistance.

To evaluate the size and geometry of thermally induced coagulation by using multipolar radiofrequency (RF) ablation and to determine a mathematic model to predict coagulation volume.Multipolar RF ablations (n = 80) were performed in ex vivo bovine livers by using three internally cooled bipolar applicators with two electrodes on the same shaft. Applicators were placed in a triangular array (spacing, 2-5 cm) and were activated in multipolar mode (power output, 75-225 W). The size and geometry of the coagulation zone, together with ablation time, were assessed. Mathematic functions were fitted, and the goodness of fit was assessed by using r(2).Coagulation volume, short-axis diameter, and ablation time were dependent on power output and applicator distance. The maximum zone of coagulation (volume, 324 cm(3); short-axis diameter, 8.4 cm; ablation time, 193 min) was induced with a power output of 75 W at an applicator distance of 5 cm. Coagulation volume and ablation time decreased as power output increased. Power outputs of 100-125 W at applicator distances of 2-4 cm led to a reasonable compromise between coagulation volume and ablation time. At 2 cm (100 W), coagulation volume, short-axis diameter, and ablation time were 66 cm(3), 4.5 cm, and 19 min, respectively; at 3 cm (100 W), 90 cm(3), 5.2 cm, and 22 min, respectively; at 4 cm (100 W), 132 cm(3), 6.1 cm, and 27 min, respectively; at 2 cm (125 W), 56 cm(3), 4.2 cm, and 9 min, respectively; at 3 cm (125 W), 73 cm(3), 4.9 cm, and 12 min, respectively; and at 4 cm (125 W), 103 cm(3), 5.5 cm, and 16 min, respectively. At applicator distances of 4 cm (125 W) and 5 cm (100 W), the zones of coagulation were not confluent. Coagulation volume (r(2) = 0.80) and RF ablation time (r(2) = 0.93) were determined by using the mathematic model.Multipolar RF ablation with three bipolar applicators may produce large volumes of confluent coagulation ex vivo. A compromise is necessary between prolonged RF ablations at lower power outputs, which produce larger volumes of coagulation, and faster RF ablations at higher power outputs, which produce smaller volumes of coagulation.

De novo lymphangiogenesis influences the course of different human diseases as diverse as chronic renal transplant rejection and tumor metastasis. The cellular mechanisms of lymphangiogenesis in human diseases are currently unknown, and could involve division of local preexisting endothelial cells or incorporation of circulating progenitors. We analyzed renal tissues of individuals with gender-mismatched transplants who had transplant rejection and high rates of overall lymphatic endothelial proliferation as well as massive chronic inflammation. Donor-derived cells were detected by in situ hybridization of the Y chromosome. We compared these tissues with biopsies of essentially normal skin and intestine, and two rare carcinomas with low rates of lymphatic endothelial proliferation that were derived from individuals with gender-mismatched bone marrow transplants. Here, we provide evidence for the participation of recipient-derived lymphatic progenitor cells in renal transplants. In contrast, lymphatic vessels of normal tissues and those around post-transplant carcinomas did not incorporate donor-derived progenitors. This indicates a stepwise mechanism of inflammation-associated de novo lymphangiogenesis, implying that potential lymphatic progenitor cells derive from the circulation, transmigrate through the connective tissue stroma, presumably in the form of macrophages, and finally incorporate into the growing lymphatic vessel.

Intravascular lymphoma is an uncommon and often overlooked form of non-Hodgkin's lymphoma characterized by extensive proliferation of lymphoid cells within the lumina of small and medium-sized vessels. Clinical symptoms of the disease are variable and often nonspecific, mostly neurologic in nature. With an aggressive course, intravascular lymphomatosis has a poor prognosis and is rarely diagnosed ante mortem. We describe here a 76-year-old woman with the clinical diagnoses of hemolytic anemia and progressive lethargy where intravascular lymphomatosis turned out as the underlying cause of the disease.

Whipple's disease (WD) is a chronic systemic inflammatory disease of infectious origin caused by Tropheryma whipplei (TW). Abdominal pain and recurrent diarrhea are usually the main symptoms leading to the suspicion of a primary bowel disease. Systemic manifestations can mimic hematologic disorders. A 49-year-old man presented with fever, weight loss, long-standing arthralgia, and diarrhea. A duodenal biopsy was unremarkable. Bone marrow histology provided no evidence of a malignant hematological disorder but revealed noncaseating granulomas. TW was detected in the bone marrow trephine by polymerase chain reaction. This is the first report to describe TW-associated granulomatous myelitis as the initially recognized organ manifestation of WD, proven at the molecular level. This observation is relevant for the differential diagnosis of patients with systemic symptoms and granulomatous diseases affecting the bone marrow, emphasizing that WD should be considered in cases of unexplained granulomatous myelitis, even when small bowel biopsy specimens are negative.

Follicular dendritic cell sarcomas (FDCSs) are very rare and usually originate in lymph nodes. We report an exceedingly rare case with localization in the dorsal mediastinum and, for the first time, provide positron emission tomography (PET) data for this tumor. This report describes the case of a 76-year-old man with a clinically aggressive tumor in the dorsal mediastinum. Computed tomography scan revealed displacement of soft tissue and lymph nodes. PET showed that the tumor had a high proliferation rate. Investigation of the successfully removed tumor mass revealed reactivity of the tumor cells for follicular dendritic cell markers and desmosomes linking adjacent tumor cells at the ultrastructural level. Marked atypia, a high mitotic rate, and areas of coagulative necrosis were found. The tumor in our case revealed the typical features and thus was classified as FDCS. In contrast to previous reports in the literature, preoperative imaging, histology, and immunohistochemistry studies indicated at least an intermediate degree of malignancy. Nevertheless, the patient made a good postoperative recovery and remained apparently disease-free 2 years later.

The rare hypocellular variants of acute leukemia (AL) previously also termed smouldering leukemia, almost always exhibit myeloid differentiation. Very rare cases of hypocellular AL with lymphoid differentiation have been reported, usually in children. This paper describes two cases (an 87-year-old woman and a 79-year-old man) in whom the blood findings were suggestive of AL. Paraffin-embedded bone marrow biopsy specimens revealed similar findings in both patients: there was severe hypocellularity, the cells of normal hemopoiesis were greatly reduced in number, and there was a diffuse increase in blast cells, which represented more than 50% of nucleated marrow cells. The blasts coexpressed TdT and CD34 and were negative for myeloperoxidase, CD117, CD68 and naphthol AS-D chloroacetate esterase. For the first time immunohistochemical Pax-5/CD34 doublestainings are provided, which revealed the blasts in one case to coexpress Pax-5 and CD34. All the blasts were CD79a-positive and 20% were also CD10-positive. In the other case, 20% of the blasts were CD79a-positive, 30% coexpressed Pax-5 and CD34 by doublestaining, and showed a clonal rearrangement of the immunoglobulin heavy chain gene. Thus a diagnosis of AL of lymphoid lineage, hypocellular variant, was made on the basis of immunohistochemical findings. The clinical course appears to be similar to that of hypocellular AML, as neither patient has developed overt leukemia during the one-year follow-up period.

Xanthogranulomatous cholecystitis is a macrophage-rich inflammatory condition of the gallbladder that occasionally presents with tumorlike appearance. In the present case the inflammation involved all the layers of the gallbladder, the surrounding connective tissue, and part of the right lobe of the liver and right transverse colon. The clinical and radiological findings were suggestive of advanced carcinoma of the gallbladder. However, intraoperative frozen section investigation revealed xanthogranulomatous cholecystitis, for which simple cholecystectomy is the treatment of choice. The original cause of the condition is unclear in most cases. In the present case it is possible that rupture of the gallbladder in association with the patient's known history of trauma have initiated the process

Primary lymphoma of the urinary bladder is a very rare tumour. A bladder tumour was found in a 57 year old man with obstructive dysuria. It was found by histological and immunohistohistochemical investigation to be an extranodal marginal zone B cell lymphoma. Lymphoepithelial lesions were absent, but were found in a clinically silent gastric lymphoma discovered four weeks later during staging investigations; this gastric lymphoma was negative for Helicobacter pylori by breath test and molecular biological analysis. Sequencing of the clonal immunoglobulin heavy chain gene in both tumours indicated the same precursor cell, of follicular or post follicular origin. In synopsis, the data suggested that this was a case of primary lymphoma of the bladder with involvement of the stomach. The application of a chromosome 3 specific alpha satellite probe revealed trisomy 3. A tumour with these characteristics arising as a lymphoma of the bladder with a metachronous involvement of the gastric mucosa has not been described previously.

Mast cells are now known to derive from CD34+ haemopoietic stem cells in the bone marrow. However, it has not yet been established whether the various types of mastocytosis, which involve tumour-like proliferation of mast cells, are true neoplastic disorders or reactive/hyperplastic conditions. In this study, tissue specimens (five bone marrow, two spleen, one skin) from female patients with histologically confirmed mastocytosis were investigated with a recently developed polymerase chain reaction assay for the determination of clonality of female cells using the human androgen receptor gene (HU-MARA). Mast cells purified to near homogeneity from hysterectomy specimens served as a control. The findings in bone marrow and skin either were not reproducible, or indicated polyclonality. However, both spleen specimens exhibited monoclonality. In addition, DNA analysis by flow cytometry was performed and revealed a diploid chromosome content with proliferation indices of under 8% in all the specimens. This is the first molecular biological study to indicate that mastocytosis is indeed neoplastic in nature.