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Extramedullary plasmacytoma of the thyroid, associated with follicular colonization and stromal deposition of polytypic immunoglobulins and major histocompatibility antigens. Possible categorization in MALT lymphoma.

A 78-year-old woman complaining of a neck mass underwent right hemithyroidectomy. The 7 x 6 cm thyroid tumor consisted predominantly of mildly atypical, epithelial membrane antigen-positive plasma cells and scattered lymphoid follicles. Features of follicular colonization (plasma cell infiltration into germinal centers) were noted. Numerous CD45RO-positive reactive T cells and a smaller number of CD20-positive blast-like B cells were also distributed among the plasma cell infiltrate. IgG, kappa-type monoclonality with J-chain reactivity was identified in the plasma cells, including those in the lymphoid follicles. The association of pre-existing lymphocytic thyroiditis was confirmed histologically in the non-tumorous thyroid tissue. The tumor exhibited deposition of reticulin fiber-rich, amorphous eosinophilic substances, provoking pronounced foreign body reactions. The deposit, polytypically immunoreactive for immunoglobulin gamma-, mu-, kappa- and lambda-chains, beta 2-microglobulin and HLA-DR, was scarcely reactive upon amyloid staining, and consisted ultrastructurally of electron-dense, non-fibrillar material and entrapped collagen fibers. Multiple myeloma was ruled out by laboratory, histologic and clinical examinations. The possible categorization of this extramedullary plasmacytoma of the thyroid within low-grade B cell lymphoma of the mucosa-associated lymphoid tissue (MALT) is discussed.

Aged↗

Primary extramedullary plasmacytoma of the orbit.

BACKGROUND: We report a case of extramedullary plasmacytoma of the orbit. This is a rare tumour which has uncommonly presented in the orbit. CASE REPORT: A 58-year-old woman presented with painless proptosis, upper lid swelling and ptosis. Incisional biopsy was performed. Clinical findings and investigations were correlated to establish the diagnosis. Treatment consisted of 35 Gy external beam radiotherapy. CONCLUSIONS: This condition is considered to be of low grade malignancy and as such can be regarded as a separate entity to multiple myeloma involving the orbit or solitary myeloma of bone in terms of treatment and prognosis.

Biopsy↗

Primary isolated extramedullary plasmacytoma of the duodenum.

The first case of primary isolated extramedullary plasmacytoma (EMP) of the duodenum is reported. The features which differentiate primary isolated EMPs from EMPs associated with multiple myeloma are discussed. The prognosis for a primary isolated EMP of the gastrointestinal tract is uncertain.

Aged↗

Radiotherapy in the management of solitary extramedullary plasmacytoma.

BACKGROUND: Solitary extramedullary plasmacytoma (SEP) is a rare tumour for which the standard treatment remains local radiotherapy (RT). We present a study of a multi-institutional experience, between 1980 and 1999, in an attempt to better understand the natural history of SEP and to identify possible prognostic factors. METHODS: The records at Radiation Oncology Victoria and Peter MacCallum Cancer Centre, Melbourne, were used for the identification of patients. The inclusion criteria were as follows: (i) histological confirmation of clonal plasma cells involving a single extramedullary site with or without lymph node involvement; (ii) no histological evidence of bone marrow involvement; (iii) no evidence of distant bone lesion on radiographic skeletal survey (bone erosions adjacent to the primary thought to be due to contiguous involvement were permitted) and (iv) no anaemia, hypercalcaemia or renal impairment due to plasma cell dyscrasia. RESULTS: A total of 16 patients was identified, with a median follow up of 66 months (range 12-211 months). The head and neck region accounted for the majority of presentations (88%). Among all patients, a serum mono-clonal paraprotein was found in three patients and bone erosion was identified in seven patients. All patients received local RT, although two patients also received elective nodal irradiation (ENI). The median RT dose was 45 Gy (range 40-50.4 Gy). Local control was achieved in all patients (100%), however, regional recurrence outside the RT fields occurred in 2/16. Multiple myeloma (MM) developed in five patients, all within 5 years. The predicted 10-year myeloma free survival is 75% and 10-year overall survival is 54%. CONCLUSION: RT can achieve excellent local control of SEP. The rate of conversion to MM is 31%. Moderate dose RT of at least 40 Gy using limited radiation fields is recommended, although ENI should be considered if toxicity is not increased.

Adult↗

Autologous stem cell transplantation in patients with high-risk plasmacytoma.

Although autologous stem cell transplantation (ASCT) is considered standard treatment in patients with multiple myeloma (MM), limited experience is available on this approach in patients with plasmacytoma (PC). Twelve patients with high-risk PC received ASCT in Finland 1994-2002. There were nine males and three females with a median age of 50 yr (32-64). Ten patients had a PC of bone, whereas two patients had extramedullary PCs. The median time from the diagnosis to ASCT was 9 months (5-100). At the time of ASCT six patients were in first complete remission (CR) or partial remission (PR), in four patients the disease was refractory to the first line therapy and two patients had relapsed. High-dose therapy consisted of melphalan (MEL)200 (n = 7), MEL200 x 2 (n = 3) or total body irradiation (TBI)-MEL140 (n = 2). No transplant-related deaths occurred. After ASCT eight patients (67%) were in CR, one patient in very good PR and one patient in PR; two patients were non-responders. With a median follow-up of 48 months from ASCT, 11 patients (92%) are alive. Six patients (50%) have relapsed or progressed 3-81 months from ASCT. ASCT is feasible in this patient population resulting in promising overall survival. A randomised trial is needed to assess the real value of ASCT when compared with other treatment options in patients with high-risk PC.

Adult↗

The bisphosphonate zoledronic acid inhibits the development of plasmacytoma induced in BALB/c mice by intraperitoneal injection of pristane.

OBJECTIVES: Bisphosphonates (BPs) are mostly used in the palliative care of myeloma-associated osteolytic lesions. Recent studies have suggested that BPs may also exert direct antitumor effects on myeloma cells. We have investigated the effect of the potent bisphosphonate, zoledronic acid (ZOL), on the development of pristane (2,6,10,14-tetramethylpentadecane)-induced plasmacytoma (PCT) in six-week-old BALB/c mice. METHODS: Different groups of pristane-treated mice also received ZOL (100 microg/kg) commencing after the development of PCT or ZOL (20 microg/kg) from the first day. Control groups received pristane alone, ZOL alone (20 microg/kg), or phosphate-buffered saline. The study was terminated on day 300, and the remaining mice were autopsied and abdominal tissues were examined histologically for PCT. RESULTS AND CONCLUSIONS: Statistical analysis revealed a significant delay in PCT development in the group receiving pristane plus ZOL (20 microg/kg) from the first day compared to the groups receiving pristane alone and pristane combined with ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.0001 and 0.0001; respectively). Kaplan-Meier analysis revealed a significant difference in survival between the group treated with pristane alone and the groups receiving pristane plus ZOL (20 microg/kg) from the first day or ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.016 and 0.023; respectively). These results indicate a direct anti-tumor effect of ZOL in pristane-induced PCT development BALB/c mice, which may contribute to their significantly increased survival. This hypothesis should now be further investigated in clinical trials.

Animals↗

Extramedullary plasmacytoma associated with a Castleman's lesion of the cervical nodes.

A rare case of extramedullary plasmacytoma seen in a patient with a Castleman's lesion is described. The mass occurred in the cervical nodes of a 61-year-old female patient, and the primary site was the intra- or peri-parotid nodes. The histological examination revealed abnormal characteristic lymph follicles and nodular proliferation of plasma cells in the same lymph nodes. The neoplastic change of plasma cells was studied on the basis of the immunoperoxidase (PAP) method. The patient is well without recurrence 15 months after total resection.

Female↗

Extramedullary plasmacytoma with crystal inclusions arising from the palatal tonsil.

A case of extramedullary plasmacytoma of the left palatal tonsil in a 51-year-old woman is reported. The histological features of the tumor are typical, except for the appearance of crystal inclusions in plasma cells, histiocytes and matrices. The developmental process and the nature of the crystal inclusions are discussed, based on electron-microscopic findings. The patient has been followed for one year post-operatively, and no clinical evidence of recurrence has been observed.

Crystallography↗

Orbital plasmacytoma in a cat.

An Abyssinian cat presented with epistaxis, melaena and retinal vascular changes. Plasma protein levels were markedly elevated and a monoclonal gammopathy was present on serum protein electrophoresis. Based on these laboratory findings, hyperviscosity syndrome was assumed to be responsible for the clinical signs. The cat responded initially to fluid therapy, but relapsed and then developed unilateral exophthalmia. The animal was euthanased and an extramedullary plasmacytoma of the right orbit was diagnosed at postmortem examination.

Animals↗

Orbital involvement by plasmacytoma. Report of two cases.

Two patients with orbital involvement of plasma cell myeloma are presented. The first patient presented an isolated plasmacytoma in the orbit; the second patient had generalized plasma cell myeloma. In both cases X-rays and computed tomographic scanning gave valuable information and biopsy confirmed the diagnosis.

Aged↗

Plasmacytoma of the uvea in a case of multiple myeloma.

A case of plasmacytoma in the uvea, both clinically and grossly anatomically mimicking a malignant melanoma, is described in a 63-year-old man who died from multiple myeloma. This is an extremely rare condition in the eye. Only one report of a similar tumour has been found in the literature.

Humans↗

Humoral immunosuppressive substance in mice bearing plasmacytomas.

The mechanism by which plasmacytomas (PC) depress the primary immune response to sheep red cells was investigated by determining the ability of normal spleen cells to produce antibody when enclosed in Millipore chambers and implanted in PC-bearing mice. Chamber-enclosed normal spleen cells implanted in PC-bearing mice responded poorly to the sheep red cells when compared to similar cells enclosed in chambers and implanted in normal mice or in mice with other lymphoid and nonlymphoid tumors. The data suggest that PC-induced immune suppression is mediated by a humoral factor.

Animals↗

Encephalomyocarditis virus infection of mouse plasmacytoma cells. II. Effect on host RNA synthesis and RNA polymerases.

The effect of encephalomyocarditis virus infection of MOPC 460 mouse plasmacytoma cells on host RNA synthesis and RNA polymerases was investigated. Consistent with work performed in other virus host systems, rates of RNA synthesis appeared to be inhibited in infected cells, whereas RNA degradation appeared normal. These results were further extended with isolated nuclei, in which distinct RNA polymerase activities could be studied under conditions where problems with RNA turnover and endogenous nucleotide pool sizes were insignificant. Endogenous nuclear RNA polymerase II activity was inhibited early postinfection and at 1 to 2 h prior to endogenous RNA polymerase I plus III activity. However, the solubilized enzymes were fully active with exogenous DNA as template. In fact, the levels of RNA polymerases I, II, and III, isolated from infected cells and nuclei, were indistinguishable from levels in uninfected cells and nuclei at each stage of their partial purification procedure. The chromatographic properties of the enzymes on DEAE-Sephadex were also unaltered. Furthermore, the RNA synthetic activity of these isolated enyzmes, or of nuclei isolated from uninfected cells, was resistant to extracts of nuclei or of cytoplasmic fractions from infected cells. These results are discussed in terms of a possible inhibition of RNA synthesis in vivo at the level of transcription initiation.

Animals↗

Isolation of a Sindbis virus variant by passage on mouse plasmacytoma cells.

A variant of Sindbis virus has been isolated by growing a stock of virus, previously passaged on chicken embryo cells, in mouse plasmacytoma (MOPC 315) cells in suspension culture. An indirect immunofluorescence test and infective center assay showed that only a small fraction of cells could be infected by the stock wild-type virus, but that the population of virus accumulating after a few passages on the mouse cells had host-range properties distinct from the stock virus. The mouse-passaged virus retained its virulence for the original host and back-passaging of this virus on chicken cells did not change its newly acquired properties. Thus, this variant appears to be a genetically distinct form of Sindbis that adsorbs to and grows much better than the stock virus on several types of mouse cells including cultures of mouse macrophages.

Animals↗

Characterization of infectious oncornaviruses from MOPC-460 plasmacytomas: their relation to A-type particles.

MOPC-460 mouse plasmacytoma cells produce intracellular A-type particles and extracellular oncornavirus-like particles ("myeloma-associated virus," abbreviated MAV). The genomes of these two particles are closely related. During attempts to establish infections with MOPC-460 extracellular particles, we isolated ecotropic and xenotropic infectious forms of murine leukemia virus. We have investigated the relation of these isolates to A-type particles and to MAV by nucleic acid hybridization. Using complementary DNA probes prepared from the two isolates, we found that these infectious murine leukemia viruses differ from A-type particles and from MAV. Moreover, we found that MAV is the predominant extracellular component: the ecotropic and xenotropic forms of murine leukemia virus were present at only low levels (less than 5%) in MAV preparations. Neither the SC-1 cells infected with ectropic murine leukemia virus nor the mink cells infected with xenotropic murine leukemia virus showed any A-type particles in their cytoplasm when examined by electron microscopy. Our inability to demonstrate infection by the A-type particle-related component, MAV, suggests that these may be defective.

Animals↗

Nonexpression of a major heat shock gene in mouse plasmacytoma MPC-11.

The major heat shock gene coding for a 68,000-dalton protein was found to be silent in mouse plasmacytoma MPC-11 in both control and stressed cells. The block appears to be at the level of transcription, although RNA processing or instability has not been ruled out. It is not caused by a major deletion or rearrangement of the gene.

Animals↗

Proviral integration site Mis-1 in rat thymomas corresponds to the pvt-1 translocation breakpoint in murine plasmacytomas.

Two loci independently implicated in T-and B-lymphocyte neoplasia are shown to be equivalent. The Mis-1 locus is a common proviral integration site in retrovirally induced rat T lymphomas, while the pvt-1 locus on murine chromosome 15 frequently translocates to the kappa locus in plasmacytomas bearing 6;15 translocations. By comparing cloned sequences, we show that pvt-1 is the murine homolog of Mis-1.

Animals↗

Interruption of two immunoglobulin heavy-chain switch regions in murine plasmacytoma P3.26Bu4 by insertion of retroviruslike element ETn.

A number of moderately reiterated murine genetic elements have been shown to have structures like those of retroviral proviruses. These elements are thought to be transposons, although little evidence of their transposability exists. Two members of one of these families of reiterated elements, the ETn family, have inserted into separate immunoglobulin heavy-chain switch regions in the plasmacytoma P3.26Bu4. Switch regions are those DNA segments associated with each immunoglobulin heavy-chain gene in which the somatic recombinations that accompany the heavy-chain switch occur. This role in somatic recombination may be relevant to the ETn insertions into the switch regions in P3.26Bu4 DNA. P3.26Bu4 and a number of other B-lineage cells contain ETn transcripts.

Animals↗