Solitary Extramedullary Plasmacytoma of the Sphenoid Sinus: A Case Report

Abstract

Solitary extramedullary plasmacytomas are rare, discrete mass of neoplastic monoclonal plasma cells in the soft tissue with no evidence of multiple myeloma. They constitute 3 % of all plasma cell tumors and less than 1 % of head and neck malignancies. A 43 year old lady presented to our clinic with complains of diplopia and headache for 4 weeks. Computed Tomography scan showed a mass lesion in the sphenoid sinus eroding the sinus floor, right wall, basisphenoid and parasellar area. A biopsy of the mass reported as plasmacytoma. Systemic examination revealed no evidence of dissemination of the disease confirming the diagnosis of a solitary extramedullary plasmacytoma. The patient was subjected to 25 fractions of radiotherapy. Here, we report a rare case of solitary extramedullary plasmacytoma of the sphenoid sinus.

Introduction

Extramedullary plasmacytomas are rare tumors accounting for 1 % of all tumors of the head and neck and 3 % of all plasma cell tumors [1, 2]. They occur at a higher rate in the aerodigestive tract with 75 % involving the nasal and paranasal sinuses [3]. However, the sphenoid sinus appears to be an exception as only a mere 1.6 % of extramedullary plasmacytomas have been reported to arise from the sphenoid sinus [4]. There is male preponderance and occurs more frequently within the sixth to eight decade of life [3]. These tumors may progress to multiple myeloma later although the numbers are significantly lesser compared to that of solitary plasmacytoma of the bone. We report a rare case of solitary extramedullary plasmacytoma of the sphenoid sinus (Fig. 1).

Fig. 1.

Mass lesion in the sphenoid sinus eroding the right wall

Case Report

A 43 year old lady presented to the ENT department with complaints of double vision and headache for 1 month. On further examination, she was noted to have right lateral rectus palsy. No other abnormalities were detected on nasoendoscopy. We subsequently proceeded with Computed Tomography Scan which reported a mass lesion in the sphenoid sinus eroding the sinus floor, right wall, basisphenoid and parasellar resion which was suggestive of carcinoma of the sphenoid sinus (Fig. 2).

Fig. 2.

Focally crushed diffuse sheets of plasmacytic cells featuring eccentric nuclei, stippled chromatic, eosinophilic cytoplam with perinuclear clearing admixture with immature plasma cells featuring enlarged, irregular nuclei, less condensed chromatin and occasional nucleoli. A few mitotic figures are appreciated

A right sphenoidotomy and biopsy of the mass was done. Histopathological examination reported focally crushed diffuse sheets of plasmacytic cells featuring eccentric nuclei, stippled chromatic, eosinophilic cytoplam with perinuclear clearing admixture with immature plasma cells featuring enlarged, irregular nuclei, less condensed chromatin and occasional nucleoli. A few mitotic figures were also appreciated. As for the immunohistochemistry, the neoplastic cells are CD 138 (+) restricted to the lambda light chain, They are negative for CD 20, LCA and pan-ck.

Several further assessments were done to exclude multiple myeloma. Bone marrow aspiration showed a normocelllular marrow with no obvious plasma cells (~1 %) and bone marrow trephine biopsy reported no significant plasma cells infiltrate except for few individual cells (CD 138+) which appears polyclonal (κ+, λ+). Skeletal surveys, serum and urine para proteins and free light chains were negative. The patient was diagnosed with solitary extramedullary plasmacytoma of the sphenoid sinus and underwent 25 fractions of radiotherapy.

Discussion

Plasmacytomas are rare tumors arising from malignant proliferation of B lymphocytes. Solitary plasmacytomas can be divided into two, extramedullary plasmacytoma or solitary bone plasmacytoma. Extramedullary plasmacytomas are rare and constitute 3 % of all plasma cell tumors [1] and less than 1 % of all head and neck malignancies [2]. 75–80 % of extramedullary plasmacytoma arise from the aerodigestive tract, the commonest site of occurence [3]. Plasmacytomas of the sphenoid sinus however, accounts for only 1.6 % of solitary extramedullary plasmacytoma according to a study by Alexiou et al. of 869 cases documented between 1905 and 1997 [4, 5].

Due to the rarity of the disease, initial guidelines or diagnostic criteria’s were difficult to establish. However, in 2004, the subgroup of the Guidelines Working group of the UK Myeloma Forum came up with several diagnostic criteria’s for extramedullary plasmacytoma. The criteria’s recommended are (1) single extramedullary mass of clonal plasma cells, (2) histologically normal marrow aspirate and trephine biopsy, (3) normal results of skeletal survey including radiology of long bones, (4) No anemia, hypercalcemia or renal impirment due to plasma dyscrasia and (5) low or absent serum or urinary levels of monoclonal immunoglobulins. Our patient fits all criteria’s mentioned [6].

Patients with extramedullary plasmacytomas frequently presents with symptoms secondary to local destruction or tumor mass. A patient with a sphenoid sinus tumor may present with features of visual loss, diplopia and facial pain due to tumor extension. Epistaxis, rhinorrhea and nasal obstruction may also be presenting features.

The histopathological criteria for extramedullary plasmacytoma has been mentioned by some authors who accepted the presence of up to 10 % of plasma cells in the bone marrow biopsy. Although there are other authors who will only accept plasma cells of less than 5 % [4].

Extramedullary plasmacytomas have been reported as having the best prognosis of all plasma cells tumors. In a study by Liebross 1999, local control was achieved in 95 % of patients with extramedullary plasmacytoma using radiotherapy [7]. In an exhaustive review of English literature done by Creach et al. [8] of all 185 patients with extramedullary plasmacytoma of the head and neck treated with radiotherapy from 1990 till 2008, a marked improvement in local control was observed at a radiotherapy dose of 40 Gy or greater. However, Sasaki et al. [9] in a study in 2011 have recommended radiotherapy combined with surgery for a better outcome.

Extramedullary plasmacytomas have good response to therapy therefore, a good prognosis. The 5 year survival rate has been reported as 88 % and a 10 year survival rate of 55 % [8]. However, patients with extramedullary plasmacytomas still face the risk of the disease progressing to multiple myeloma. In a study by Bachar et al. [10] in 2008, the percentage of progression to multiple myeloma was 28 % over a period of 10 years. Long term follow up is therefore crucial as conversion cases from extramedullary plasmacytoma to multiple myeloma have been documented even to occur 28 years after the diagnosis of a solitary lesion [11]. The progression is characterized by the presence of bony lesions, bone marrow plasmacytosis nad monoclonal proteins [12].

Conclusion

Extramedullary plasmacytomas are a rare form of plasmacytoma mostly arising from the aerodigestive tract and respond well to radiotherapy therefore having a good prognosis. Long term follow up however is necessary to assess for conversion to multiple myeloma and to detect radiation induced malignancies.

Compliance with Ethical Standards

Conflict of interest

The author declare that there is no conflict of interest.

Human Rights

This article does not contain any study with human participants performed by the author.

Informed Consent

Informed consent was obtained from the participant in the study.