|Year : 2016 | Volume
| Issue : 1 | Page : 26-29
Extramedullary plasmacytoma of oral cavity: Series of three unusual cases at unusual locations
Abhishek Purkayastha, Neelam Sharma, Virender Suhag, Nishant Lohia
Department of Radiation Oncology, Army Hospital Research and Referral, New Delhi, India
|Date of Web Publication||21-Jul-2016|
Department of Radiation Oncology, Army Hospital Research and Referral, Dhaula Kuan, Delhi Cantt, New Delhi - 110 010
Source of Support: None, Conflict of Interest: None
Plasmacytoma is a monoclonal neoplastic proliferation of plasma cells of unknown etiology, presenting as a solitary discrete mass either in soft tissue as extramedullary plasmacytoma (EMP) or in bone as solitary bone plasmacytoma or as disseminated multiple myeloma (MM). EMP is a very rare manifestation, accounting for approximately 3% of all plasma cell neoplasms and <1% of all head and neck malignancies, with oral cavity being the rarest. We hereby report a series of three unusual cases of EMP, involving buccal mucosa, hard palate, and right retromolar trigone, rarely reported in literature, treated with definite radiotherapy after immunohistochemical studies confirmed the diagnosis. At present, patients are on regular follow-up without evidence of progression to MM. This series is presented with review of literature to highlight the extremely uncommon sites in head and neck where this disease entity can manifest, thus posing a diagnostic and therapeutic dilemma for treating physicians.
Keywords: Buccal mucosa, extramedullary plasmacytoma, hard palate, oral cavity, retromolar trigone
|How to cite this article:|
Purkayastha A, Sharma N, Suhag V, Lohia N. Extramedullary plasmacytoma of oral cavity: Series of three unusual cases at unusual locations. Int J Oral Health Sci 2016;6:26-9
|How to cite this URL:|
Purkayastha A, Sharma N, Suhag V, Lohia N. Extramedullary plasmacytoma of oral cavity: Series of three unusual cases at unusual locations. Int J Oral Health Sci [serial online] 2016 [cited 2019 Aug 20];6:26-9. Available from: http://www.ijohsjournal.org/text.asp?2016/6/1/26/186661
| Introduction|| |
Extramedullary plasmacytoma (EMP) is an extremely rare B-lymphocytic plasma cell dyscrasia originating from soft tissues,  accounting for <1% of all head and neck malignancies.  Paranasal sinuses  and nasopharynx are the most common locations. Oral cavity is the rarest site of EMP and can be misdiagnosed with other oral cavity lesions such as a squamous cell carcinoma, lymphoma, sarcoma, melanoma, or a metastatic lesion. Radiotherapy (RT) has been the definite treatment modality in view of radiosensitivity of EMPs  and also to spare the morbidity of surgery while chemotherapy plays its role in recurrent and refractory disease. 
| Case Reports|| |
A 42-year-old male presented with 4 cm × 3 cm right and 3 cm × 2 cm left buccal mucosa growths [Figure 1] of 3 months duration. Biopsy from lesion showed sheets of small, round cells [Figure 2] consistent with plasmacytoma as immunohistochemistry (IHC) was positive for kappa light chain, immunoglobulin G (IgG), CD38 [Figure 3], CD138 [Figure 4], CD45, and epithelial membrane antigen (EMA) while negative for CD20, CD3, CD5, CD56, lambda light chain, vimentin, CD99, cytokeratin (CK), desmin, melan A, and synaptophysin. He was planned for RT with three-dimensional conformal RT (3-DCRT) technique to a dose of 40 gray (Gy) in 20 fractions at 200 centigray (cGy) per fraction; however, midway during therapy, he lost to treatment and did not follow up.
|Figure 2: Punch biopsy from buccal mucosa lesion showing sheets of small round cells (H and E, ×100)|
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A 44-year-old male presented with 6 cm × 5 cm exophytic growth over hard palate [Figure 5] of 4 months duration. Biopsy revealed small, round cells with IHC positive for kappa light chain, CD 45, B-cell lymphomas-2 (BCL-2), CD38, and CD138 while negative for lambda, CD20, CD56, CK, vimentin, CD99, CD40, synaptophysin, chromogranin, and human melanoma black-45 (HMB-45) suggestive of plasmacytoma. The patient was treated with conformal RT to a dose of 50 Gy in 25 fractions at 200 cGy per fraction, 5 days a week.
A 53-year-old female presented with 4 cm × 3 cm swelling on the right retromolar trigone (RMT) [Figure 6] for 3 months. Biopsy revealed small, round cell tumor with IHC positive for CD38, CD138, and kappa light chain while negative for lambda, CK, CD56, CD20, vimentin, neuron-specific enolase, chromogranin, synaptophysin, CD99, CD40, melan A, and S-100, confirming the diagnosis of EMP, and was treated with 3-DCRT to dose of 40 Gy in 20 fractions at 200 cGy per fraction, 5 days a week.
|Figure 6: Third patient with soft-tissue lesion involving right retromolar trigone|
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Initial computed tomography (CT) scan of face and neck showed localized disease while positron emission tomography scan was negative for metastasis. All cases were evaluated for multiple myeloma (MM), with no evidence of anemia, hypercalcemia, renal dysfunction, or raised monoclonal Igs. Bone marrow aspirate showed <5% plasma cells, and skeletal survey did not show any solitary or multiple osteolytic bony lesions. No cervical lymph nodes were palpable. The second and third patients tolerated complete RT schedule well with complete resolution of oral lesions and without evidence of plasma cells on bone marrow examination. At present, both are on regular follow-up over 6 months without progression to MM.
| Discussion|| |
EMP comprises <1% of all head and neck (H and N) tumors.  The most common H and N sites are nasal cavity,  nasopharynx, paranasal sinuses, larynx, and oropharynx while oral cavity involvement is rarely seen. Bachar et al.  in 2008 reported EMP in 68 patients, Zuo et al.  in 2011 reported only a solitary case of alveolar EMP, and Ozturk et al.  in 2013 reported a single case of EMP of buccal mucosa while Nair et al.  in 2014 described one case of EMP of lower gingiva with cervical lymphadenopathy.
We hereby report EMP of bilateral buccal mucosa, hard palate, and RMT, rarely reported in world literature till date. EMP can mimic benign oral cavity lesions such as fibromas, pyogenic granulomas, papillomas, pleomorphic adenomas, and malignant lesions such as squamous cell carcinoma, immunoblastic lymphoma, marginal zone lymphoma, diffuse large BCL, melanoma, sarcomas, or even metastasis from another primary. Cervical lymph node involvement may be seen in 30-40% cases,  which was not seen in our patients.
The recommended diagnostic criteria for EMP are single extramedullary mass of clonal plasma cells, normal results in skeletal survey including radiology of long bones without evidence of osteolytic lesion, no anemia, hypercalcaemia or renal impairment and absent or low serum or urinary level of monoclonal immunoglobulin (Igs). Bone marrow biopsy shows < 5% plasma cells with no clonal proliferation. Since the morphologic characteristics of EMP may resemble those of extramedullary invasion of a well-differentiated MM, the possibility of MM should be omitted before confirming the diagnosis of EMP.
Histopathology showing monoclonal plasma cells exhibiting kappa or lambda light chain and Igs on IHC can confirm the diagnosis. CD138 and CD38 are specific markers while CD45, BCL-2, and EMA are nonspecific for EMP, which differentiates from a carcinoma which stains for CK and CD40. CD56 is expressed in 70% cases of MM as compared to 10% EMP. CD20 expressed by lymphomas and T-cell antigens such as CD3 and CD5 were negative. Melan A, HMB-45 and S-100 for melanoma, CD99, vimentin, and desmin for sarcoma were negative. Synaptophysin and chromogranin were negative suggesting no involvement of oral cavity by neuroendocrine tumors. Based on these findings, the lesions were diagnosed as EMP of oral cavity.
Plasma cell neoplasms are highly radiosensitive and, therefore, RT is considered the primary treatment.  Surgery remains an alternate option for resectable lesions followed by adjuvant RT in margin-positive cases.  Proposed RT dosage is 40 Gy for lesions <5 cm and 50 Gy for lesions more than 5 cm,  giving a 90% local control.  Chemotherapy is considered for recurrent or refractory cases progressing to MM using melphalan, cyclophosphamide, and corticosteroids. 
The most important prognostic factor determining the outcome posttherapy is progression to MM as seen in 10-30% cases. High grade, bulky lesion, and kappa chain have more chances for dissemination.  RT remains the definitive therapy for causing local regression and preventing dissemination of disease, thus increasing overall survival with a 10 years rate of 70%.  By reporting this series, we recommend that a high degree of clinical suspicion and histopathological confirmation is required to identify and diagnose EMP whenever any patient presents with a soft tissue growth in the oral cavity so as to prevent any inappropriate treatment causing undue morbidity or even mortality.
We would like to thank the patients for allowing to publish the case report and use the images taken during their stay in hospital. We also like to extend our gratitude to the Department of Pathology, Department of Nuclear Medicine, and Department of Radiology, Army Hospital (Research and Referral), New Delhi, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
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