Extramedullary plasmacytoma with associated multiple myeloma as a presentation of the posterior mediastinal mass: a rare clinical encounter.

A plasmacytoma is a single, isolated tumour of abnormal plasma cells. It can develop within the bone, known as solitary plasmacytoma of bone, or outside the bone, referred to as extraosseous (extramedullary) plasmacytoma, without spreading to other parts of the body. Plasmacytoma, an uncommon presentation in the posterior mediastinum, usually arises as solitary or multiple lesions in bone or soft tissues. The standard treatment involves definitive radiotherapy, potentially curative for extramedullary cases. The prognosis varies, being more favourable without concurrent multiple myeloma and worsening with high-risk cytogenetics. The case involves a male in his early 80s with an extensive medical history presenting with difficulty swallowing and dyspnoea. The diagnosis revealed a rare posterior mediastinal plasmacytoma associated with multiple myeloma, emphasising the importance of prompt diagnosis and treatment.

Skull base plasmacytoma in young patients aged below 40 years: Radiological perspectives and clinical outcomes.

BACKGROUND: Plasmacytoma of the skull base is a rare manifestation of plasma cell neoplasm with only a few cases documented in literature involving young adults. Plasmacytoma can be an isolated solitary lesion or a secondary manifestation of multiple myeloma (MM). In this study, we report the clinical and radiological characteristics, management, and outcomes of patients under the age of 40 who presented with skull base plasmacytoma and associated neurological manifestations. Additionally, we share our experience in treating a rare case of skull base plasmacytoma diagnosed during pregnancy, in which the patient exhibited a favorable response to myeloma treatment initiated after delivery. CASE SERIES: Four patients were identified, comprising one pregnant female and three male patients, with a median age of 36 years (range 33-37 years). The main presenting symptoms were headache, dizziness, and cranial nerve palsy. All patients received underwent systemic myeloma therapy and radiotherapy with three patients also underwent autologous stem cell transplantation (ASCT). Notably, all patients achieved complete remission. CONCLUSION: Skull base plasmacytoma represents a rare manifestation of plasma cell neoplasms, underscoring the importance of considering it in the differential diagnosis of skull base lesions to ensure early intervention and avoid potential serious complications. Throughout our series, the cornerstone of therapy involved radiotherapy, systemic myeloma therapy, and ASCT, all of which elicited a favorable response in every case.

Cutaneous plasmacytoma with Mott cell differentiation in a dog.

Cytologic evaluation of aspirate slides from a small, <1-cm, interdigital mass on a 9-y-old, spayed female Yorkshire Terrier revealed a proliferation of discrete, round cells containing few-to-many, variably sized, round, eosinophilic, cytoplasmic inclusions. The top differentials based on the cytologic findings were either a plasma cell tumor or a B-cell lymphoma with Mott cell differentiation. The unencapsulated, well-demarcated, multilobulated round-cell neoplasm was completely excised. Immunohistochemical stains were performed to further characterize the neoplasm, which had immunolabeling for multiple myeloma oncogene 1 and vimentin, but did not react with CD3, CD20, melan A, or ionized calcium-binding adapter molecule 1, nor with a Giemsa special stain. Ultrastructurally, the cytoplasmic granules had Russell body-like morphology. A solitary, cutaneous plasmacytoma with Mott cell differentiation has not been described previously in veterinary medicine, to our knowledge.

Isolated Abducens Nerve Palsy: A Rare Manifestation of Recurrent Extramedullary Myeloma.

Multiple myeloma is a plasma cell neoplasm, which may present as a solitary plasmacytoma and, uncommonly, as an extramedullary plasmacytoma. Intracranial plasmacytomas may manifest in central nervous system involvement as cranial nerve palsies. Cranial nerve six palsy is the most common in cases of malignancy. However, isolated abducens palsy presenting as multiple myeloma recurrence is very uncommon. Here, we detail two cases in which intracranial plasmacytoma lesions were present within the region of the Dorello canal, resulting in acute isolated unilateral diplopia from disease recurrence in the absence of systemic marrow involvement.

IgA multiple myeloma-associated mediastinal spinal plasmacytoma presenting as spinal cord compression.

Multiple myeloma associated with extramedullary plasmacytoma at initial presentation is rare. We describe a case of a man in his 30s who initially presented with symptoms of spinal cord compression. Further imaging revealed a mediastinal tumour, with a biopsy confirming plasmacytoma. Immunofixation revealed IgA lambda paraprotein. Bone marrow biopsy demonstrated atypical T-cell cytotoxic proliferation and trilineage hypoplasia. The patient was diagnosed with extramedullary plasmacytoma with active IgA multiple myeloma. The patient received mediastinal radiation to the tumour, followed by anti-myeloma therapy. This diagnosis is critical as managing a solitary plasmacytoma drastically differs from an extramedullary plasmacytoma with active multiple myeloma.

Solitary bone plasmacytoma: Long-term clinical outcomes in a single center.

BACKGROUND: A solitary plasmacytoma is classified into a solitary plasmacytoma of the bone (SBP) and a solitary extramedullary (soft tissue mass) plasmacytoma, based on the site of the lesion. Despite the high local control rate with radiotherapy, approximately half of patients' conditions progress to multiple myeloma (MM) within 3-5 years after diagnosis, with SBP having a worse prognosis. PATIENTS AND METHODS: We retrospectively assessed the treatment and outcomes of patients with SBP in a hospital in China from 2008 to 2021. Twenty-four patients treated over 13 years with SBP were enrolled in this retrospective study. RESULTS: The most common sites for SBP were the axial skeleton and femur. The M protein was detected in 11 patients (46 %), of which 8 (33 %) had light chains, 2 (8 %) had immunoglobulin G kappa and 1 (4 %) had immunoglobulin D kappa. Flow cytometry revealed that 5 patients (21 %) had minimal bone marrow involvement. The treatment included chemotherapy, surgery, and radiotherapy in 18 (75 %), 12 (50 %), and 9 (38 %) patients, respectively, of whom 13 (54 %) received combined treatment. Over a median follow-up period of 67.2 months, 9 patients (38 %) developed MM in a median time of 101.5 months. The 5- and 10-year progression-free survival rates were 67.3 % and 37.4 %, respectively. One patient died due to pneumonia without progression and the other died due to relapse. CONCLUSION: This study confirmed the high rate of progression of SBP to MM, indicating a need for adjunct chemotherapy for the management of SBP.

A Plasmacytoma of the Lateral Pharyngeal Wall: A Diagnostic Enigma.

Plasmacytoma is a rare plasma cell dyscrasia that grows in bones or soft tissues such as the pharynx. Soft tissue plasmacytomas are rare, and a higher burden has been reported in the upper aero-digestive tract, often manifesting as hoarseness, dysphagia, or odynophagia. Due to their rarity, extramedullary plasmacytomas (EMPs) have unknown prognostic factors, and guidelines for optimal management are still lacking. However, radiation therapy and surgery have been used with positive outcomes. Herein, we describe a unique case of plasmacytoma of the pharyngeal tissue in a male patient with a history of HIV disease. The patient completed 28 sessions of radiation therapy, resulting in an improvement in his throat pain and hoarseness. Given the patient's age and lack of traditional risk factors for head and neck cancers, his hoarseness and odynophagia proved to be a diagnostic conundrum. Although infrequent, soft tissue plasmacytomas should be considered in the differential diagnosis of head and neck tumors.

18 F-FDG PET/CT in Solitary Extramedullary Plasmacytoma of the Penis.

ABSTRACT: A 72-year-old man presented with a painless penile mass for 3 months. Contrast-enhanced CT revealed heterogeneous enhancement, whereas 18 F-FDG PET/CT displayed inhomogeneous 18 F-FDG accumulation in the lesion without other abnormal activity. The histopathological examination from biopsied specimen confirmed the diagnosis of a plasmacytoma. However, the subsequent tests, including serum/urine immunofixation electrophoresis, serum/urine free light chain assay, and bone marrow smear/biopsy, did not show any abnormalities. The conclusive diagnosis was a solitary extramedullary plasmacytoma of the penis.

Megalosplenia as an initial manifestation of multiple myeloma with a novel CYLD gene mutation: A case report and literature review.

INTRODUCTION: Megalosplenia in newly diagnosed multiple myeloma (MM) is extremely rare, posing diagnostic and therapeutic challenges due to its unusual location and clinical manifestations and lack of optimal therapeutic strategies. CASE PRESENTATION: A 65-year-old female who was previously healthy presented with a history of ecchymosis on her right leg accompanied by progressive fatigue for 2 weeks. She was admitted to our center in July 2019 due to thrombocytopenia. The patient presented with megalosplenia, anemia, monoclonal protein (λ-light chain type) in the serum and urine, and 45.6% malignant plasma cells in the bone marrow. Splenectomy was performed due to persistent splenomegaly after 3 cycles of the bortezomib plus dexamethasone regimen, and immunohistochemistry results indicated λ-plasmacytoma of the spleen. The same cytogenetic and molecular abnormalities, including t(14;16), 14q32 amplification, 16q32 amplification, 20q12 amplification, and a novel CYLD gene mutation, were identified using fluorescence in situ hybridization and next-generation sequencing in both bone marrow and spleen samples. Therefore, a diagnosis of MM (λ-light chain type, DS III, ISS III, R-ISS III, high-risk) with spleen infiltration was proposed. The patient did not achieve remission after induction treatment with bortezomib plus lenalidomide and dexamethasone or salvage therapy with daratumumab plus ixazomib and dexamethasone. However, she ultimately did achieve very good partial remission with a regimen of bendamustine plus lenalidomide and dexamethasone. Unfortunately, she died of pneumonia associated with chemotherapy. CONCLUSION: To our knowledge, only 8 cases of spleen plasmacytoma at MM diagnosis have been described previously. Extramedullary myeloma patients with spleen involvement at diagnosis are younger and that the condition is usually accompanied by splenic rupture with aggressive clinical features and poor prognosis. Further studies are needed to explore pathogenesis and effective therapies to prolong the survival of such patients.

Spontaneous regression of multiple solitary plasmacytoma harboring Epstein-Barr virus: a case report and literature review.

We report a rare case of spontaneous regression (SR) in an elderly untreated patient with multiple solitary plasmacytoma (MSP). Diagnosis of MSP was confirmed through surgical resection of the left nasal cavity mass and subsequent biopsy of the right humerus. The patient was considered ineligible for chemotherapy due to poor performance status. At 3-month post-diagnosis, the patient's condition worsened with deteriorating bone lesions and emergence of a new serum monoclonal protein. However, these clinical findings completely disappeared at 6 months, and positron emission tomography-computed tomography at 1 year confirmed complete metabolic remission. Notably, peripheral blood lymphocyte counts were inversely correlated with tumor progression and remission. Pathological re-evaluation of the initial biopsy specimens revealed programmed cell death protein 1 (PD-1) expression in tumor-infiltrating CD8+ T cells. In addition, tumor cells were infected with Epstein-Barr virus (EBV) but were negative for programmed cell death ligand 1 (PD-L1) expression, which is the most potent immune escape mechanism in tumor cells. While the mechanism underlying SR remains unclear, our findings suggest that host immune response as well as EBV infection may contribute to SR. Further studies are needed to elucidate the clinicopathologic mechanisms of tumor regression in plasma cell neoplasms.

Plasmacytoma and Amyloid Lymphadenopathy, FDG, and Fluorocholine.

ABSTRACT: A 56-year-old man with thoracal mass suspected of solitary plasmacytoma was referred for 18 F-FDG PET-CT scan. His PET-CT revealed FDG-avid rib mass and cervical lesion at level 2. He also underwent 18 F-fluorocholine (FCH) PET-CT to evaluate possible metastatic spread of the disease. FCH PET-CT showed increased uptake at the rib mass, while the cervical lesion was not FCH-avid. Biopsies confirmed rib lesion was a solitary plasmacytoma; however, the cervical lesion was an amyloid deposited lymph node. This case showed FCH PET-CT is a valuable companion of FDG scan for the evaluation of plasma cell dyscrasias with a better specificity.

Successful Treatment of Refractory Orbital Plasmacytoma with Chimeric Antigen Receptor T Cell Therapy: A Case Report and Review of the Literature.

Orbital plasmacytoma is a rare plasma cell tumor that may arise as an aggressive form of extramedullary multiple myeloma. Treatment modalities include surgical excision, radiation, and chemotherapy. Chimeric antigen receptor T cell therapy is currently reserved for refractory disease. The authors present a case of a 69-year-old woman with an extensive orbital plasmacytoma refractory to multimodal therapy who was treated with idecabtagene vicleucel chimeric antigen receptor T cell therapy. Four days after infusion, the patient exhibited grade 1 cytokine release syndrome, which resolved with tocilizumab. The orbital plasmacytoma significantly decreased in size 1 month after treatment and demonstrated complete serological response and sustained tumor burden reduction at 10-month follow-up. This case highlights the efficacy of chimeric antigen receptor T cell therapy for refractory orbital plasmacytoma and calls attention to potential inflammatory toxicities.

[Consensus for the diagnosis and management of extramedullary plasmacytoma in China(2024)].

Extramedullary plasmacytoma (EMP) is a special type of malignant plasmacytosis, which is complex and heterogeneous. Most EMP patients have poor prognosis and lack a stratified prognostic system or ideal treatment strategy supported by evidence-based medical evidence, which cannot meet clinical needs. In order to improve the understanding of this disease entity, Plasma Cell Disease Group, Chinese Society of Hematology, Chinese Medical Association and Chinese Myeloma Committee-Chinese Hematology Association developed the "Chinese Expert Consensus on the diagnosis and treatment of extramedullary plasmacytoma", which aims to standardize the clinical diagnosis and treatment of EMP and ultimately improve the overall survival of patients with plasmacytoma.

Recurrence of solitary plasmacytoma in the liver 10 years after the onset of multiple bone lesions.

A 79-year-old man presented with a history of solitary plasmacytoma in the bone 10 years ago. Chemoradiotherapy was effective, and remission was maintained with intermittent treatment at relapse of the bone lesions. One year after the last treatment, a follow-up computed tomography (CT) scan revealed multiple liver masses, and a liver biopsy revealed plasmacytoma. There was no clonal plasma cell infiltration in the bone marrow, and the final diagnosis was solitary plasmacytomas of the liver. Although liver involvement is known in relapsed refractory multiple myeloma, solitary plasmacytoma in the relapsed stage confined to the liver is rare, and all previous reports have been from the initial presentation. To the best of our knowledge, this is the first recurrent case of solitary plasmacytoma of the liver.

Extramedullary plasmacytoma of the larynx - Case report.

Extramedullary plasmacytoma of the larynx is an extremely rare entity accounting for 0.04-0.45% of malignant tumours of the larynx. The objective of this clinical case report is to highlight the diagnosis and management of a unique case such as this. A 77-year-old gentleman presented with complaints of hoarseness for 1 year. Computed tomography image revealed a soft tissue mass lesion involving the right true vocal cord. Direct laryngoscopic biopsy was performed and subjected to histopathological examination, which showed collection of plasma cells. Immunohistochemistry confirmed the presence of Kappa and Lambda cells. Multiple myeloma (MM) was ruled out. The patient received radical intent radiation therapy using 3DCRT technique with a dose of 50Gy in 25# over 5 weeks. He experienced improvement in hoarseness on subsequent follow-up visits. At 1-year follow up, positron emission tomography computed tomography showed near total resolution of disease with no progression to MM. Radiation therapy alone is known to achieve good local control, recurrence free survival, and organ preservation in such cases.

Enhanced clinical outcomes with radiotherapy in diagnostically challenging intracranial plasmacytomas: Analysis of 190 cases.

BACKGROUND: Intracranial plasmacytomas are rare tumors arising from plasma cells with approximately half of the cases progressing to multiple myeloma (MM). However, there is a lack of comprehensive clinical cohort analysis on the clinical and pathological features, progression, and outcomes of intracranial plasmacytomas. METHODS: A retrospective analysis of 190 cases was conducted, combining data from 38 cases in a single institution and 152 cases from the literature. Patient demographics, clinical presentations, tumor locations, imaging features, surgical treatments, and follow-up outcomes were collected and analyzed. Survival analysis and Cox regression analysis were performed to identify prognostic factors. RESULTS: A total of 190 intracranial plasmacytoma patients with an average age of 55.4 years were included in the study. The preoperative misdiagnosis ratio was high at 55.3%, and 59.7% of the tumors affected the calvaria convexity, compared to 40.3% located at the skull base. Resection and biopsy were achieved in 72.4% and 27.6% patients, respectively. Among them, 34.2% (65/190) of patients were initially diagnosed with MM with intracranial plasmacytoma as their first presentation (MM-IPFP), while 63.2% (120/190) of patients were diagnosed with solitary intracranial plasmacytoma (SIP), including 61 extramedullary plasmacytomas and 59 solitary bone plasmacytomas. In the SIP group, 22.4% (24/107) of patients experienced disease progression leading to the development of MM during a median follow-up time of 42.6 months (range 1-230 months). Multivariate analysis unveiled that radiotherapy (HR, 0.05; 95% CI, 0.00-0.87; p = 0.04), not surgery, was a protective prognostic factor for overall survival in MM-IPFP patients. Comparison between the SIP progression group and non-progression group revealed a significant difference of Ki-67 index (non-progression vs. SIP progression, 8.82% ± 7.03 vs. 16.5% ± 10.5, p < 0.05). AUC analysis determined that a cutoff value of 9.0% was the best predictor of SIP progression, with an area under the curve of 0.712. CONCLUSIONS: This retrospective clinical analysis highlights the potential role of radiotherapy, rather than surgical resection, in improving the outcomes of intracranial plasmacytoma. Additionally, the Ki-67 index is identified as a valuable marker for predicting disease progression. This would provide some evidence for the paradigm of diagnosis and treatment modalities for intracranial plasmacytomas from the large cohort.

Case with translating to multiple myeloma at 8 years after radiation therapy for extramedullary plasmacytoma of the larynx.

We report a case of extramedullary plasmacytoma of the larynx that was eradicated by radiotherapy; however, 8 years later, the disease had progressed to multiple myeloma. A mid -60s Japanese woman presented with a right-sided arytenoid mass in the larynx who underwent biopsy at another hospital. Based on the biopsy results, the patient was diagnosed with extramedullary plasma cell tumour and was referred to the Department of Otorhinolaryngology at our hospital. She received radiotherapy (50.4 Gy) and the laryngeal tumour was eradicated. Positron emission tomography/CT (PET-CT) revealed no abnormal accumulation in the larynx or whole body. After radiotherapy, the department of otorhinolaryngology, in consultation with Ddepartment of haematology performed follow-ups using laryngoscope, blood examination and PET-CT. Five years after the end of radiotherapy, the patient had no local recurrence or transition to multiple myeloma. However, 8 years later, blood examination and PET-CT revealed multiple myeloma. Laryngoscopy did not reveal any recurrent laryngeal tumour. Therefore, chemotherapy for multiple myeloma was administered at the department of haematology. Three months after the initiation of chemotherapy, the accumulation had disappeared in PET-CT. Three years have passed since chemotherapy initiation. At present, no recurrence or metastasis was observed in the larynx or whole body.

Skeletal muscle extramedullary plasmacytoma transformed into plasmablastic plasmacytoma: a case report.

BACKGROUND: Extramedullary plasmacytoma (EMP) is a rare plasma cell malignancy, especially when the tumor originates in skeletal muscle. Plasmablastic plasmacytoma is an anaplastic round cell tumor with highly malignancy and poor prognosis. To date, there have been no reports on the transformation of skeletal muscle EMP into plasmablastic plasmacytoma. Therefore, the diagnosis, treatment, and prognosis of cases of this pathologic transformation are unclear. CASE PRESENTATION: This article reports a case of an elderly male patient who presented with a painless mass in the right calf and was diagnosed with EMP by puncture pathology. Complete remission was obtained after sequential chemoradiotherapy. 6 months later, another puncture was performed due to plasmablastic plasmacytoma multiple distant metastases, and the pathology showed that EMP was transformed to plasmablastic plasmacytoma. Despite aggressive antitumor therapy, the disease continued to deteriorate, and the patient ultimately died of respiratory failure. CONCLUSION: The transformation of EMP into plasmablastic plasmacytoma is very rare, and its diagnosis and treatment require the participation of both experienced pathologists and clinicians. We report this case in order to raise clinicians' awareness of the diagnosis and treatment of EMP and its transformation to plasmablastic plasmacytoma, and to avoid misdiagnosis and underdiagnosis.