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PubMed1991

Ascites revealing peritoneal and hepatic extramedullary hematopoiesis with peliosis in agnogenic myeloid metaplasia: case report and review of the literature.

A 61-year-old man presented with ascites in the course of agnogenic myeloid metaplasia (AMM). Ascitic fluid was exudative and contained mature and immature leukocytes, erythroid cells, and megakaryocytes as observed on a bone marrow smear. Peritoneal biopsy showed myeloid metaplasia, and liver biopsy revealed intrasinusoidal myeloid metaplasia and peliosis. Ascites cleared after abdominal radiotherapy but treatment resulted in transient aplasia. Subsequently, portal hypertension was demonstrated by hepatic transjugular catheterization. Complications of splenomegaly led to splenectomy and splenorenal shunt followed by fatal acute hepatitis and septic shock. A review of the literature and an analysis of mechanisms of ascites occurring in AMM, especially peritoneal implants of myeloid tissue and occurrence of peliosis in myeloproliferative disorders, are presented.

Adult↗

PubMed1987

Induction of epidermal mucous metaplasia by culture of recombinants of undifferentiated epidermis and retinol-treated dermis in a chemically defined medium.

Epidermal mucous metaplasia of cultured skin is known to be induced by excess retinol. Studies were made on whether retinol affects primarily the epidermis or the dermis during retinol-induced epidermal mucous metaplasia of 13-day-old chick embryonic skin in culture. When recombinants of 13-day-old normal epidermis and retinol-treated dermis were cultured for 7 days in chemically defined medium in the absence of retinol, hormones, and serum, they showed altered epidermal differentiation toward secretory epithelium (mucous metaplasia). Thus retinol acted primarily on dermal cells.

Animals↗

PubMed1997

The 28K protein in urinary bladder, squamous metaplasia and urine is triosephosphate isomerase.

OBJECTIVES: The objective of this study was to establish the identity of a protein found in high concentrations in squamous metaplasia of the bladder. DESIGN AND METHODS: The protein was isolated and subjected to a series of physical, chemical, and catalytic studies. RESULTS: In the normal urothelium the protein was confined to a juxtanuclear pattern on the luminal side of the umbrella cells; in squamous metaplasia and squamous cell carcinoma the protein was increased and exhibited a more diffuse intracellular distribution. The protein was found to be identical to triosephosphate isomerase (EC 5.3.1.1; TPI) with respect to its immunological properties, native and subunit molecular weights, electrophoretic mobility, catalytic activity, and amino acid sequence. CONCLUSIONS: While the basis for the altered distribution of TPI remains to be established, the increased amounts of the protein in urine or bladder tissue may be indicative of squamous metaplasia, squamous cell carcinoma, or other bladder injuries.

Carcinoma, Squamous Cell↗

PubMed1988

Bone metaplasia in the urinary tract: a new radiological sign.

We report 7 cases of bone tissue in the upper urinary tract. Routine excretory urography was suspicious for renal lithiasis. However, pathological evaluation of the kidney tissue revealed bone metaplasia in all 7 cases. Retrospective examination of the first 6 cases showed a typical radiological sign, consisting of a radiopaque eccentric halo surrounding an area of lesser radiological density that, in turn, connected with the urothelium. These findings permitted a correct preoperative diagnosis of bone metaplasia in case 7. Accurate preoperative differentiation of bone metaplasia (false calculi) and true renal lithiasis is important owing to the different treatments required.

Adult↗

PubMed1999

Differential expression of Hsp27 in normal oesophagus, Barrett's metaplasia and oesophageal adenocarcinomas.

The protein expression patterns of normal, metaplastic and malignant oesophageal tissues were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to identify changes associated with Barrett's metaplasia and transformation to oesophageal adenocarcinoma. Heat-shock protein 27 (Hsp27), a small heat-shock protein which is protective against cytotoxic stresses, was abundant in normal oesophagus. However, Hsp27 expression was markedly lower in Barrett's metaplasia and oesophageal adenocarcinomas. This was confirmed by immunohistochemical analysis. Hsp27 protein was most highly expressed in the upper layers of squamous epithelium and exhibited a pattern of expression that corresponded with the degree of squamous maturation. Northern and Southern analysis demonstrated Hsp27 to be regulated at the level of mRNA transcription or abundance. Normal oesophageal tissues were examined for gender differences in Hsp27 expression. Women expressed fourfold higher levels of Hsp27 mRNA, however, this difference was not appreciable in protein expression. Hsp27 protein was inducible by heat shock in Barrett's adenocarcinoma cell lines and an immortalized oesophageal epithelial cell line (HET-1A), but not by oestradiol. These results demonstrate abundant constitutive expression of the stress-response protein Hsp27 in the normal oesophagus, and suggest that low-level expression in Barrett's metaplasia may be one factor which may influence susceptibility to oesophageal adenocarcinoma development.

Adenocarcinoma↗

PubMed1999

The Italian Consensus Conference on Diagnostic Criteria for Myelofibrosis with Myeloid Metaplasia.

The purpose of this work was to develop a definition of myelofibrosis with myeloid metaplasia (MMM) using diagnostic criteria that would remain valid within the set of patients with chronic myeloproliferative disorders or myelodysplastic syndromes. A list of 12 names for the disease and 37 diagnostic criteria were proposed to a Consensus Panel of 12 Italian experts who ranked them in order so as to identify a core set of criteria. The Panel was then asked to score the diagnosis of 46 patient profiles as appropriate or not appropriate for MMM. Using the experts' consensus as the gold standard, the performance of 90 possible definitions of the disease obtained through the core set was evaluated. 'Myelofibrosis with myeloid metaplasia' ranked as the preferred name of the disease. Necessary criteria consisted of 'diffuse bone marrow fibrosis' and 'absence of Philadelphia chromosome or BCR-ABL rearrangement in peripheral blood cells'. The six optional criteria in the core set consisted of: splenomegaly of any grade; anisopoikilocytosis with tear-drop erythrocytes; the presence of circulating immature myeloid cells; the presence of circulating erythroblasts: the presence of clusters of megakaryoblasts and anomalous megakaryocytes in bone marrow sections; myeloid metaplasia. The definition of the disease with the highest final score was as follows: necessary criteria plus any other two criteria when splenomegaly is present or any four when splenomegaly is absent. The use of this definition will help to standardize the conduct and reporting of clinical studies and should help practitioners in clinical practice.

Humans↗

PubMed2001

Comparison of methylene blue-directed biopsies and conventional biopsies in the detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a preliminary study.

BACKGROUND: The diagnostic advantage of methylene blue (MB) chromoendoscopy in Barrett's esophagus is unclear. METHODS: Patients with columnar-lined esophagus (CLE) were enrolled into a prospective, randomized crossover trial of MB-directed biopsy versus conventional biopsy. RESULTS: Forty-seven patients (19 long-segment CLE; 28 short-segment CLE) were enrolled and underwent MB-directed biopsy. Sensitivity and specificity of MB for specialized intestinal metaplasia were 53% and 51%, respectively. Sensitivity and specificity of MB for dysplasia were 51% and 48%, respectively. Thirty-five patients (15 long-segment CLE; 20 short-segment CLE) completed the crossover trial. Relative frequencies for specialized intestinal metaplasia were 73% and 71% from MB-directed and conventional biopsy specimens, respectively (p = 0.73). Relative frequencies for dysplasia were 20% and 18% from MB-directed and conventional biopsy specimens, respectively (p = 0.65). In patients with long-segment CLE, dysplasia was diagnosed in 10 patients with MB and 7 patients with conventional biopsy methods (p = 0.25). The number of biopsy specimens per EGD was greater with MB, which may have influenced the diagnosis. Histologically, the grade of dysplasia was indefinite/low in nearly all of the dysplastic specimens. CONCLUSIONS: Results of MB-directed biopsy were similar to conventional biopsy in detecting specialized intestinal metaplasia and indefinite/low-grade dysplasia. MB was not useful in short-segment Barrett's esophagus.

Barrett Esophagus↗

PubMed1998

Overexpression of transforming growth factor beta1 in arterial endothelium causes hyperplasia, apoptosis, and cartilaginous metaplasia.

Uninjured rat arteries transduced with an adenoviral vector expressing an active form of transforming growth factor beta1 (TGF-beta1) developed a cellular and matrix-rich neointima, with cartilaginous metaplasia of the vascular media. Explant cultures of transduced arteries showed that secretion of active TGF-beta1 ceased by 4 weeks, the time of maximal intimal thickening. Between 4 and 8 weeks, the cartilaginous metaplasia resolved and the intimal lesions regressed almost completely, in large part because of massive apoptosis. Thus, locally expressed TGF-beta1 promotes intimal growth and appears to cause transdifferentiation of vascular smooth muscle cells into chondrocytes. Moreover, TGF-beta1 withdrawal is associated with regression of vascular lesions. These data suggest an unexpected plasticity of the adult vascular smooth muscle cell phenotype and provide an etiology for cartilaginous metaplasia of the arterial wall. Our observations may help to reconcile divergent views of the role of TGF-beta1 in vascular disease.

Animals↗

PubMed2002

Cyclooxygenase-2 expression in early gastric cancer, intestinal metaplasia and Helicobacter pylori infection.

Cyclooxygenase (COX) is the crucial enzyme for synthesis of prostaglandins and occurs in two isoforms COX-1 and COX-2. Whilst COX-1 is constantly expressed in the gastrointestinal tract in large quantities and probably maintains mucosal integrity through constant generation of prostaglandins, COX-2 is induced principally during inflammation. In early gastric cancer and in intestinal metaplasia the expression of COX-2 in patients infected by Helicobacter pylori is increased in intestinal type compared to diffuse type gastric cancer and in intestinal metaplasia. In tumours of mixed type, COX-2 is also increased in the intestinal component compared to the diffuse component. Whilst there has been success of COX-2 inhibition for chemoprevention in colon cancer, a similar role in gastric cancer needs to be carefully assessed in the light of reported adverse effects and whether the precancerous condition, intestinal metaplasia, can truly regress.

Cyclooxygenase 2↗

PubMed1978

The stability of vitamin A-induced metaplasia of mouse vibrissa follicles in vitro.

Tests were made of the stability of the previously described glandular morphogenesis and mucous metaplasia of embryonic mouse vibrissa follicles produced in vitro by excess vitamin A. The changes in individual follicles were observed in living tissue explants and serial sections. Upper lip skin of 13.5-day embryos underwent budding from vibrissa follicles to form branching glands which secreted mucus after 10--14 days in medium containing 4.7 microgram/ml retinol. If this medium was replaced with standard medium after 7 days, glandular morphogenesis and metaplasia continued unaffected, although some hair follicle bases returned to their original morphogenetic program. Similar results were obtained with skin of 13-day embryos treated with vitamin A (6.0 MG/ML) for only 3 days. The moderate degree of glandular morphogenesis in 15-day skin with vitamin A (4.7 microgram/ml) was not altered by the simultaneous addition of a high dose of cortisol (18 microgram/ml). It is suggested that the initiation of glandular morphogenesis of follicles differs from the initiation of mucous metaplasia in embryonic chick epidermis by vitamin A, in that it resembles a new secondary embryonic induction rather than a modulation of the epithelium.

Animals↗

PubMed1985

Intestinal metaplasia induced by X-irradiation in different strains of rats.

Attempts were made to examine strain differences in the susceptibility of rats to intestinal metaplasia induced by X-irradiation. The gastric regions of 4 inbred male rats (SHR, F344, WKY, and LEW strains) in 5-week-old and 2 random bred male rats (SD, and WIS strains) were irradiated with a total dose of 20 Gy X-ray given in two equal fractions separated by three days. Upon sacrifice at 6 months after the last irradiation, the number of intestinal metaplastic crypts with positive reaction to alkaline phosphatase (ALP) appeared highest in the SHR and lowest in the WIS rats. Morphologically, the number of crypts with intestinal metaplasia in whole glandular stomachs of SHR, WIS, F344, and SD rats were higher than those in WKY and LEW rats. In the pyloric gland, it was highest in WIS rats, while in the fundic gland it was highest in SHR rats. The results show that the appearance and location of intestinal metaplasia by X-irradiation are greatly influenced by the strain of the rat.

Alkaline Phosphatase↗

PubMed1986

Uterine tumor resembling ovarian sex-cord tumor with osteoid metaplasia.

A rare uterine tumor showing sex-cord-like differentiation and marked osteoid metaplasia was found in a 33-year-old female. The tumor, occupying the uterine fundus, was multilobular, fleshy, and yellowish white, with punctations and poorly defined tumor margins into the subserosa. The tumor nodules were mostly composed of small, round, rather regular neoplastic cells with scanty cytoplasm and prominent nuclei. Epithelioid neoplastic cells with striking ovarian sex-cord-like arrangement, surrounded by fibrous tissue, were noticed. Polygonal neoplastic cells with marked osteoid metaplasia were also detected. The authors introduce an infrequent variant of uterine tumor resembling ovarian sex-cord tumor with osteoid metaplasia, probably of endometrial stromal cell origin. Because of deep myometrial infiltration without vascular invasion, malignant potential is considered. The patient is now alive without evidence of local recurrence or distant metastasis after abdominal total hysterectomy.

Adult↗

PubMed1994

Agnogenic myeloid metaplasia in childhood: a report of two cases and efficiency of intravenous high dose methylprednisolone treatment.

Myelofibrosis with myeloid metaplasia, or agnogenic myeloid metaplasia (AMM) is a chronic myeloproliferative disorder characterized by fibrosis of the bone marrow accompanied by aniso- and poikilocytosis, leukoerythroblastosis and hepatosplenomegaly with extramedullary hematopoiesis. Agnogenic myeloid metaplasia is very rare in children. In this report, two cases of AMM in whom the onset of the illness were at 3 and 12 months of age, are presented. Both had severe anemia, hepatosplenomegaly and bone marrow fibrosis. Lymph node biopsy of the first patient and liver biopsy of the second revealed extramedullary hematopoiesis. They were treated with an intravenous high dose of methylprednisolone (daily 30 mg/kg for 3 days, 20 mg/kg for 4 days, 10 mg/kg for 1 week, 5 mg/kg for 1 week). A complete improvement of hematological and clinical findings was observed.

Anemia↗

PubMed1981

'Early' splenectomy and survival in agnogenic myeloid metaplasia. An analysis of 338 cases published since 1940.

The data available for 338 cases of splenectomy in agnogenic myeloid metaplasia published since 1940 were retrieved from the literature and analyzed. The median survival of cases operated upon at an early stage of the disease (as judged by their hemoglobin level, platelet number, and splenic size) was compared with the survival reported in conservatively treated patients diagnosed at an early stage of agnogenic myeloid metaplasia. Survival time since diagnosis of patients with early splenectomy was similar to, or shorter than, that reported in conservatively treated patients with early agnogenic myeloid metaplasia.

Humans↗

PubMed2006

Giant hepatic adenoma with bone marrow metaplasia not associated with oral contraceptive intake.

BACKGROUND: Hepatocellular adenomas are the most common benign liver tumors. They are usually related to oral contraceptive intake. CASE PRESENTATION: This case describes a 58-year-old woman admitted to our institution for a hepatic mass incidentally discovered during a routine examination. The patient, who was never on oral contraceptives, was asymptomatic upon admission. She underwent a thorough diagnostic evaluation and then a hepatic right trisegmentectomy. The histologic evaluation of the mass showed that it was a hepatocellular adenoma with areas of bone marrow metaplasia. CONCLUSION: Bone marrow metaplasia has rarely been found associated to liver tumors. The presence of marrow-derived hepatic progenitor cells might be the source of both adenoma hepatocytes and bone marrow differentiated cells. To our knowledge, this is only the second case in the English literature in which areas of bone marrow metaplasia were found in a hepatocellular adenoma.

Journal Article↗

PubMed1984

Subdural hemorrhage secondary to extramedullary hematopoiesis in postpolycythemic myeloid metaplasia.

A 64-year-old woman with a 20-year history of polycythemia vera and a 2-month history of postpolycythemic myeloid metaplasia ( PPMM ) became comatose because of bilateral subdural hematomas. Biopsy of the dura mater at operation demonstrated extramedullary hematopoiesis ( EMH ). The subdural hemorrhage was secondary to dural invasion by hematopoietic tissue and vascular dilation with a predisposing element of thrombocytopenia. This is the second case of central nervous system (CNS) EMH in a case of polycythemia vera. Only 8 cases of symptomatic CNS EMH and 16 cases overall have been reported, and these were primarily due to agnogenic myeloid metaplasia. Symptoms were secondary to the mass effect of dural tumor-like hematopoietic tissue or to an elevated cerebrospinal fluid protein content. The survival after a diagnosis of PPMM with CNS EMH has been less than 6 months in all cases. CNS EMH is an unusual and a potentially critical complication of polycythemia vera that should be considered in the evaluation of the patient with polycythemia vera and myeloid metaplasia.

Craniotomy↗

PubMed1999

Splenic myeloid metaplasia, histiocytosis, and hypersplenism in the dog (65 cases).

Splenectomy specimens from 65 dogs with severe, diffuse, sustained, and progressive splenomegaly were examined. The clinical signs, hematology, and serum chemistry values in for the dogs were not useful diagnostic features. Microscopic changes in the spleens were distinctive and consisted of 1) myeloid metaplasia, 2) histiocytosis, 3) erythrophagocytosis, and 4) thrombosis with segmental infarction. Ultrastructural features suggested proliferative changes in the splenic reticular cells and macrophages (reticular meshwork) that described a continuum from reactive changes associated with immunologic damage of erythrocytes to neoplastic proliferation of histiocytic components. Thirty percent of the dogs survived 12 months. Approximately one half (53%) of the dogs with complete postmortem evaluations showed multiorgan involvement with a tissue distribution and cell morphology consistent with histiocytic neoplasia. For the remaining dogs (47%), only splenic pathology was consistently present, and a specific cause of death was often not evident. Distinctive histologic changes in the splenic tissues-including mitotic activity, erythrophagocytosis, giant cell formation, thrombosis/ infarction, and the proportion and distribution of histiocytic and hematopoietic cells-were statistically evaluated for prognostic relevance. The presence of giant cells was the only reliable prognostic feature, and that was indicative of a fatal outcome. These descriptive changes of myeloid metaplasia in the canine spleen are compared with the human clinical and pathologic syndromes of 1) agnogenic myeloid metaplasia, 2) hemophagocytic syndromes, and 3) hypersplenism. These diseases in humans produce histopathologic changes in the spleen that are similar to those observed in the canine splenic tissue we examined in this study.

Animals↗

PubMed1976

[Role of Bruch's membrane in the process of metaplasia of the ocular pigmented epithelium of Xenopus laevis].

The metaplasia of pigmented epithelium into retina with the formation of nuclear and reticular layers took place in the experiments with wrapping a sheet of pigmented epithelium from tadpoles up in the Bruch's membrane of adult frogs X. laevis. The implant with de novo formed retina resembled the inverted eye. In those experiments where the Bruch's membrane of tadpoles came into contact with that of adults only depigmentation of the pigmented epithelium cells was observed. The pigmented epithelium metaplasia suggests that the Bruch's membrane is permeable not only for low molecular weight substances, but also for inducing agents. The adult Bruch's membrane serves in the process of metaplasia in the experiments described as a new and limiting system which ensures more orderly formation of new retina.

Animals↗