Plasma cell neoplasms are a heterogeneous group of diseases and solitary plasmacytomas are even less common. These lesions consist of monoclonal plasma cells (1, 2). Extramedullary plasmacytoma (EMP) are rare tumors and usually detected in head and neck area with incident rate of 0.04 in 100000 people (3, 4). They are usually present in lymphoid tissues of nasal cavity, paranasal sinuses and nasopharynx (4, 5). Oropharyngeal EMP is a rare type of plasmacytomas, and here we have reported a case, treatment and 2 years follow up.
Our patient was a 57-year-old man with 2 months history of dysphagia with a foreign body sensation. Patient was visited by an ENT specialist and a lesion was detected on oropharynx during physical examination. Spiral CT scan without contrast of paranasal sinuses showed a suspicious soft tissue density in hypopharynx at level of epiglottis. His Neck MRI with and without contrast showed oropharyngeal polypoid projection suggesting a malignant tumor in the right lateral aspect of oropharynx (figure 1-2). This mass was excised and the pathology result confirmed plasmacytoma (fig 3). All laboratory tests, including CBC, BUN Cr, liver function tests, ESR, Calcium, Phosphor, serum protein electrophoresis and bone marrow biopsy were normal. Patient received 40 Gy radiation in 20 fraction into tumor bed. After 24 months of follow up the patient is well and disease free.
Figure1. Axial CT image without contrast shows a soft tissue lesion (white arrow) in right side of oropharynx
Figure 2. T2W and T1W MR images (Pre and post contrast) showing an enhancing lesion (white arrows) in right side of oropharynx, which has inhomogeneous iso and hyposignal on T1W images and inhomogeneous iso and hypersignal on T2W images.
Figure 3. infiltration of monomorphic neoplastic plasma cells with scant cytoplasm under the respiratory epithelium of oropharynx. hematoxylin and eosin (x100)
Solitary plasmacytomas are monoclonal plasma cells proliferation outside bone marrow and consist 3-5% of plasma cell neoplasms. When a patient with plasmacytoma has renal insufficiency, bone lesions, anemia, hypercalcemia, and bone marrow involvement by plasma cells, the disease has progressed to multiple myeloma. It seems that the disease behavior is different when it occurs in bone or outside the bone (6-8). In a large series of 25 patients, the most common site of extramedulary plasmacytoma, was paranasal sinus (2). In a series of 13 patients in our center, the most common site was nasopharymx and paranasal sinus. Until that time we had no case of oropharyngeal plasmacytoma (9).
Plasmacytoma is a rare disease and its prognosis in extramedulary plasmacytoma is better than bone plasmacytoma (4-6). However, in a series of 84 patients with plasmacytoma, 7 local recurrences had occurred. Five local recurrences were observed among 25 patients with extramedullary plasmacytoma and 2 local recurrences were reported in 59 patients with bone plasmacytoma. In this report, progression to multiple myeloma in patients with bone plasmacytoma was higher than extramedullary plasmacytoma. After 5 years, 56% of patients with bone plasmacytoma and 30% of extramedullary plasmacytoma developed multiple myeloma (2).
In a study by Ozsahin, the mean age of 256 patients with solitary plasmacytoma was 60 years and male/female ratio was 1.8. The mean age of patients in our center with solitary extramedullary plasmacytoma, was 51 years with male/female ratio of 10/3. The present case was a 57 year old man (6, 9).
Treating solitary plasmacytoma is controversial and data comes from retrospective studies. Although there is no well designed prospective study, the treatment of choice is surgery and RT. The role of radical surgery is up for debate (6, 10). Multiple programs for RT are used in different centers. Some authors believe that larger doses are better than lower doses, but in Ozsahin’s study no difference was found (6). Our patient underwent surgery combined with RT with a dose of 40 Gy in 20 fractions.
In Ozsahin’s study, 5 and 10-year survival rate of patients with solitary plasmacytoma was 54-74%. In this study, age was a significant factor in progression to multiple myeloma (6) and other studies have shown similar results. The 5 year survival of 59 patients reported by Reed was 78% (2). We followed up this patient for 24 months and he is still disease free.
Lesion size in our patient was 60*25 mm, and some authors have stated that size is a prognostic factor. Ozsahin found that plasmacytoms that are less than 4 cm have a better prognosis (6). But in other studies size was not an important factor (2).
Conclusion: according to the presented case, a plasmacytoma should be considered in patients with dysphagia and oropharyngeal lesion. These masses can be treated with surgical excision and radiotherapy.
The authors wish to thank Mr. H. Argasi at the Research Consultation Center (RCC) of Shiraz University of Medical Sciences for his invaluable assistance in editing this manuscript.
AM and MK presented the case and drafted the manuscript. SB and ESK helped in manuscript drafting and data presentation. DJ and HS helped in manuscript drafting and designed the study. All authors have approved the final version of manuscript.
Conflict of Interest Disclosures:
There are no conflicts of interest in terms of the present manuscript.
A written informed consent was signed by patient for reporting his case. All the personal information remained anonymous.