Solitary bone plasmacytoma as posterior fossa cranial neoplasia, presentation of two clinical cases

Background: Solitary bone plasmacytoma is a plasmatic cell dyscrasia; its presentation in the posterior fossa is very rare. Case Description: We present two cases, a 59-year-old male and a 50-year-old female, both with heterogeneous clinical presentation. One had symptoms compatible with endocranial hypertension, and the other presented with a hemispheric cerebellar syndrome and ipsilateral trigeminal neuralgia. They were both related to an intraosseous tumor of the occipital region near the torcula with large extension to the posterior fossa. The diagnosis of a plasma cell neoplasm arising from the diploe of the squamous portion of the occipital bone was confirmed with immunohistochemistry. Conclusion: The treatment for a cranial tumor that is suspected to be a solitary bone plasmacytoma requires a multidisciplinary team to diagnose, plan a total resection, and after surgery continue with the follow-up of the patient. Solitary bone plasmacytoma should be considered as a differential diagnosis for a tumor that produces cancellous bone widening without sclerotic borders.

A case of solitary plasmacytoma of bone showing co-expression of both immunoglobulin light chains

Background Solitary plasmacytoma of bone (SPB) is a rare plasma cell neoplasm. It arises in bone as a single locus in the absence of any plasma cell myeloma lesions. Plasma cell neoplasms intrinsically express only one immunoglobulin light chain (IgL)—kappa or lambda—and using this fact, kappa/lambda deviation is the decisive factor for diagnosis. Co-expression of both IgLs in a single tumor cell is extremely rare. Case presentation We report a case of SPB that arose in the vertebra of a 52-year-old Japanese woman. Histologically, the resected mass showed diffuse plasma cell proliferation. Dual IgL expression was detected by flow cytometry, immunohistochemistry, and in situ hybridization (ISH) targeting IgL mRNA. Conclusion We have presented an extremely rare case of SPB showing dual expression of kappa and lambda IgLs. This unusual case of plasma cell neoplasia might represent a possible exceptional example of failure of “IgL isotypic exclusion.”

A novel differential diagnosis for diffuse cavitating nodules: primary pulmonary plasmacytoma

Background Extramedullary plasmacytoma is a rare monoclonal plasma cell neoplasm that originates from tissues other than the bone marrow and constitutes only 3%–5% of all plasma cell neoplasms. Most cases involve the upper respiratory tract. Extramedullary plasmacytoma involving the lung is extremely rare. Primary pulmonary plasmacytoma is a rare type of extramedullary plasmacytoma, usually presenting with a nodule or mass in hilar region. Literature search has shown very few cases of immunohistochemically confirmed cases of pulmonary plasmacytoma. Diffuse pulmonary infiltration is an unusual presentation. Case presentation We report the case of a 56 year old lady with history of cough and breathlessness since one month. Computed Tomography revealed diffusely scattered multiple cavitating nodules and consolidation in both lungs. Computed Tomography guided biopsy of one of the lung nodules was done. Histopathologic examination and immunohistochemistry showed features of pulmonary plasmacytoma .This is an unique case of primary pulmonary plasmacytoma with the rare presentation as diffusely scattered multiple cavitating nodules and consolidation. According to our literature search, primary pulmonary plasmacytoma manifesting as cavitating nodules is being reported for the first time. Conclusions Primary pulmonary plasmacytoma should be also be considered in the differential diagnosis of multiple diffusely scattered cavitating lung nodules.

Refractory primary extramedullary plasmacytoma in kidney: a case report

Extramedullary plasmacytoma (EMP) is a rare plasma cell neoplasm, with the majority (80–90% of cases) occurring in the upper aerodigestive tract. To our best knowledge, primary EMP from renal tissues is extremely rare. Herein, the diagnosis and treatment of a refractory primary EMP with renal involvement in a 53-year-old male patient is reported. The patient received radical nephrectomy followed by radiotherapy, and showed relapse 3 months after treatment. The cancer cells were sensitive to subsequent chemotherapy, however, the patient died of infection associated with the disease after almost 3.5 years following first presentation.

A Case of Solitary Plasmacytoma of Bone Showing Coexpression of Both Immunoglobulin Light Chains

Background: Solitary plasmacytoma of bone (SPB) is a rare plasma cell neoplasm. It arises in bone as a single locus in the absence of any plasma cell myeloma lesions. Plasma cell neoplasms intrinsically express only one immunoglobulin light chain (IgL) – kappa or lambda – and using this fact, kappa/lambda deviation is the decisive factor for diagnosis. Coexpression of both IgLs in a single tumor cell is extremely rare.Case presentation: We report a case of SPB that arose in the vertebra of a 52-year-old Japanese woman. Histologically, the resected mass showed diffuse plasma cell proliferation. Dual IgL expression was detected by flow cytometry, immunohistochemistry and in situ hybridization (ISH) targeting IgL mRNA.Conclusion: We have presented an extremely rare case of SPB showing dual expression of kappa and lambda IgLs. This unusual case of plasma cell neoplasia might represent a possible exceptional example of failure of “IgL isotypic exclusion”.

Proteasome Inhibitors and Their Pharmacokinetics, Pharmacodynamics, and Metabolism

The proteasome is responsible for mediating intracellular protein degradation and regulating cellular function with impact on tumor and immune effector cell biology. The proteasome is found predominantly in two forms, the constitutive proteasome and the immunoproteasome. It has been validated as a therapeutic drug target through regulatory approval with 2 distinct chemical classes of small molecular inhibitors (boronic acid derivatives and peptide epoxyketones), including 3 compounds, bortezomib (VELCADE), carfilzomib (KYPROLIS), and ixazomib (NINLARO), for use in the treatment of the plasma cell neoplasm, multiple myeloma. Additionally, a selective inhibitor of immunoproteasome (KZR-616) is being developed for the treatment of autoimmune diseases. Here, we compare and contrast the pharmacokinetics (PK), pharmacodynamics (PD), and metabolism of these 2 classes of compounds in preclinical models and clinical studies. The distinct metabolism of peptide epoxyketones, which is primarily mediated by microsomal epoxide hydrolase, is highlighted and postulated as a favorable property for the development of this class of compound in chronic conditions.

Development of B-lymphoblastic leukemia in patients treated for multiple myeloma – A case series of 14 patients

Development of B-lymphoblastic leukemia/lymphoma (BALL) is uncommon in patients with plasma cell neoplasm (PCN). Currently, little is known about risk factors for and characteristics of BALL arising in patients who have undergone treatment for PCN. We reviewed the clinicopathologic features of 14 patients with PCN who developed subsequent BALL and assessed the clonal relationship between these two neoplasms in 5 of the 14 patients. Clinical and laboratory data were extracted from the electronic medical record in accordance with an institutional review board-approved protocol. For the IgH clonality studies DNA was extracted from formalin fixed paraffin embedded tissue and analyzed utilizing the LymphoTrack® IGH FR2/3 Assay -- S5/PGM™ reagents from Invivoscribe Technologies. Next-generation sequencing of libraries was performed on a ThermoFisher Scientific Ion Torrent S5™ sequencer. The LymphoTrack® Software - S5/PGM™ Version 2.4.5 was used to analyze the IGH rearrangement sequences and relative proportion of the sequences was determined as a percentage of total sequencing reads. All PCN patients in our cohort received an autologous stem cell transplant (auto-SCT) with subsequent lenalidomide maintenance therapy. The mean time from the start of lenalidomide treatment after auto-SCT to BALL development was 62 months. None of the BALL cases were Philadelphia chromosome-positive. There was increased incidence of TP53 mutations and deletions (36%). IgH clones were identified in all but one sample. Comparison of the IgH clones from the original PCN and subsequent BALL revealed distinct clones in all 5 patients tested. In 2 of the 5 patients, the original PCN clone was also identified along with the distinct BALL clone. Our study reveals that BALL cases arising in patients with treated PCN are not clonally related to the original disease, and may represent therapy-related malignancy associated to prior treatment including lenalidomide maintenance therapy. More studies are needed to establish the incidence and understand the pathogenesis of this possible therapy-related complication.

A rare case of plasmacytoma of mandible revealing plasma cell myeloma

Multiple myeloma (MM) is a malignant proliferation of plasma cells with multiple foci. Plasmacytoma is a solitary plasma cell neoplasm involving a single bone. The most commonly involved bone is vertebra. Jaw bones are rarely involved as a first bone as they have lesser hematopoietic marrow. A solitary plasmacytoma may progress to multiple myeloma within few months to year. We present a case of a swelling of mandible that on further investigations confirmed the diagnosis of multiple myeloma. We have discussed the course of treatment given and its prognosis. Keywords: multiple myeloma; plasmacytoma of jaw; bence jones Protein; abnormal plasma cells; CD138.