Plasmacytoma of nasopharynx - A rare case presentation treated with volumetric modulated arc technique radiotherapy

Sujata Sarkar; Irfan Bashir; Roopesh Reddy Yotham; Ritesh Sharma

doi:10.4103/jrcr.jrcr_6_22

CASE REPORT

Year : 2023 | Volume : 14 | Issue : 1 | Page : 43-45

Plasmacytoma of nasopharynx - A rare case presentation treated with volumetric modulated arc technique radiotherapy

Sujata Sarkar, Irfan Bashir, Roopesh Reddy Yotham, Ritesh Sharma
Department of Radiotherapy, Batra Hospital and Medical Research Centre, New Delhi, India

Date of Submission	21-Jan-2022
Date of Decision	10-Mar-2022
Date of Acceptance	11-Mar-2022
Date of Web Publication	02-Aug-2022

Correspondence Address:
Dr. Sujata Sarkar
Department of Radiotherapy, Batra Hospital and Medical Research Centre, New Delhi
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jrcr.jrcr_6_22

Abstract

Extramedullary plasmacytomas (EMPs) are solitary plasma cell neoplasms that involve sites other than bone or bone marrow. It constitutes only 0.4% of tumors of head-and-neck region. Surgery and radiotherapy are standard treatment, depending on the site. Radiotherapy promises 90–100% local control rate and prolonged survival. Here, we are reporting a case of plasmacytoma nasopharynx treated with volumetric-modulated arc technique (VMAT) radiotherapy, with contouring details, dose to target, and nearby structures. Patient had complete response and is relapse free for the past 3 years with minimal toxicity. In our case, the lesion is in nasopharynx and is about 1cm, as such it required precise radiotherapy technique like VMAT, to give targeted dose delivery and sparing the nearby critical organs.

Keywords: Extramedullary plasmacytomas, nasopharynx, solitary, volumetric-modulated arc technique radiotherapy

How to cite this article:
Sarkar S, Bashir I, Yotham RR, Sharma R. Plasmacytoma of nasopharynx - A rare case presentation treated with volumetric modulated arc technique radiotherapy. J Radiat Cancer Res 2023;14:43-5

How to cite this URL:
Sarkar S, Bashir I, Yotham RR, Sharma R. Plasmacytoma of nasopharynx - A rare case presentation treated with volumetric modulated arc technique radiotherapy. J Radiat Cancer Res [serial online] 2023 [cited 2023 Jun 7];14:43-5. Available from: https://www.journalrcr.org/text.asp?2023/14/1/43/353193

Introduction

Extramedullary plasmacytomas (EMPs) are isolated plasma cell tumors arising from a nonosseous site. It constitutes 1/3^rd of solitary plasmacytoma and ~2% of all plasma cell disorders.^[1],[2] Plasmacytoma is more common in males, with age group of 55–65 years.^[3] It constitutes 4% of all nonepithelial tumors of nasal cavity and 0.4% of all head-and-neck cancers.^[4] The most common site for EMPs is upper aerodigestive tract.^[5] The most common location in head and neck is nasal septum.^[6] Clinically, it presents with nonspecific symptoms such as nasal congestion, anosmia, hyposmia, epistaxis, rhinorrhea, pain; obstruction of aerodigestive tract is usually seen in advanced stage.^[7],[8] Standard treatment of EMP is radiotherapy. Here, we are presenting a rare case of plasmacytoma nasopharynx in a 64-year-old female, treated with volumetric-modulated arc technique (VMAT) radiotherapy who had complete response even at 3 years of follow-up, with minimal toxicity.

Case Report

A 64-year-old female presented in August 18 with multiple episodes of epistaxis for 1.5 years. She had diabetes mellitus and hypothyroidism for the past 7 years. Endoscopy showed a lesion in the nasopharynx. Biopsy revealed it to be plasma cell dyscrasia. On immunohistochmistry, it was CD56+, negative for cyclin D1, ALK; MIB 5%. Bone marrow biopsy, renal parameters, and LDH were normal. MRI showed mass in posterosuperior wall of nasopharynx/skull base junction, in midline measuring 16 mm × 16 mm × 17 mm. Positron emission tomography–computed tomography (PET-CT) showed an fluorodeoxyglucose avid (SUV max 6.75) soft tissue mass 1.1 cm × 0.9 cm involving nasopharynx [Figure 1]a.

Figure 1: (a) Positron emission tomography–computed tomography scan showed fluorodeoxyglucose-avid soft tissue mass involving nasopharynx. (b) Contouring images with Gross tumor volume - blue, Clinical target volume - green, Planning target volume - red. (c) Color wash showing 95% coverage of planning target volume by prescribed dose. (d) Dose Volume Histogram showing Organ at risks and Planning target volume coverage [details in Supplementary Table 1]

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Patient was planned for radiotherapy in November–December 2018 through VMAT to a dose of 45Gy/25 Fractions (Fr) at 1.8Gy/Fr, 1Fr/day, and 5Fr/week. Gross tumor volume (GTV- red) was contoured by fusing PET-CT scan with planning CT. Clinical target volume (CTV- pink) was contoured with 1.5 cm margin on GTV to cover microscopic disease. Planning target volume - blue was contoured with 5 mm margin on CTV to account for uncertainties in beam alignment, patient positioning, or any movement [Figure 1]b and [Figure 1]c. VMAT ensures targeted dose delivery to such small lesions with least dosage or toxicity to surrounding organs at risk (OARs) such as eyes, brainstem, pituitary, cochlea, and parotid glands [Figure 1]d. OARs' doses were within limits [Supplementary Table 1][Additional file 1]. Patient tolerated radiation well. There was no hematologic toxicity, grade1 fatigue, and grade 1 mucositis during radiation according to Common Terminology Criteria for Adverse Events v4.0.^[9] Informed and written consent was obtained from the patient to publish this case report, investigation reports, and images.

PET-CT after 3 months showed complete response. Complete blood count, serum calcium, urine analysis were within normal limits. Patient is now asymptomatic, on follow-up for the past 3 years and the last PET-CT done in September' 2021 showed no metabolically active lesion.

Discussion

Plasmacytomas are of 3 types. The first and most common type is multiple myeloma. It is characterized by abnormal M protein and is usually disseminated. The other 2 types, solitary plasmacytoma of bone (SBP) and EMP, are quite rare. Diagnostic criteria of EMP are (i) histopathological presence of monoclonal plasma cells in an extramedullary region; (ii) no bone marrow involvement; (iii) negative skeletal survey; (iv) no anemia, hypercalcemia, or renal impairment due to plasma cell dyscrasia; (v) low serum or urinary levels of monoclonal immunoglobulin.^[10]

EMP clinical staging by Wilshaw method:^[11] Stage I - Limited to an extramedullary site; Stage II - Involvement of regional lymph node; Stage III - Multiple metastases. Male:female ratio is 3:1. Risk factors include viral pathogenesis and chronic irritation from inhaled irritants.^[12],[13]

Radiotherapy is the standard of care for EMP. EMPs are radiosensitive, with a local control rate of 90%–100%.^[14] Dose of 40–50 Gy to EMP in nasopharynx is usually recommended.^[15]

Follow-up includes radiological and electrophoresis assessment to detect recurrences and progression to myeloma (10%–30% frequency).^[14] EMP has a myeloma-free survival at 10 years of 71.2% while SBP has 0%.^[16] The overall 10-year survival was 70%.^[17]

Conclusion

Due to rare incidence of plasmacytoma of nasopharynx, there is limited data on radiotherapy contouring guidelines. There is 90%–100% local control rate with radiotherapy, with minimal long-term toxicity. Further trials are required to focus on proper treatment guidelines including the radiotherapy contouring and optimal dose to improve recurrence-free survival as well as quality of life.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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