A 58-year-old Caucasian male was referred to the otolaryngology outpatient clinic from the oncology department with a complaint of a right-upper neck mass which had been growing for one year. The mass was painless and had rapidly increased in size during the preceding 3 months. The patient reported no loss of weight and had no other masses. He denied swallowing or breathing difficulties. There was no history of exposure to tuberculosis. He was a farmer and life-long nonsmoker. On physical examination, he was a well-nourished man with a palpable, freely mobile nontender right level II lymph node measuring 3 cm x 3 cm. Oropharyngeal examination showed a moderately enlarged right tonsil. The rest of the physical examination was unremarkable. Rigid direct laryngoscopy showed a normal laryngopharynx and hypopharynx.
Due to a possible vascular relation to the mass, an MRI of the neck was done, showing a sharply defined ovoid 3 x 3 x 4.5 cm nonspecific soft tissue mass with heterogeneous enhancement, likely a lymph node, with a mass-like bulge in the right tonsillar fossa suspicious for a primary tumour (Figure 1). This supported the clinical diagnosis of a tonsillar primary lesion with a regional nodal deposit.
Two previous fine-needle aspirates (FNAs) of the neck mass had already been undertaken by the oncologists, but these were inconclusive. The aspirates were heavily blood stained and showed small tissue fragments composed of small lymphoid cells admixed with histiocytes. The sparse material suggested an inflammatory/reactive process, and flow cytometry was nondiagnostic. Therefore an excision biopsy with frozen sections was recommended for definitive diagnosis. If this revealed a squamous cell carcinoma, the operation would proceed to a selective neck dissection. The patient consented to the procedure and underwent a right tonsillectomy and excision of the enlarged lymph node. Frozen sections suggested a plasmacytoma and therefore a neck dissection was not carried out.
Histologies of both the tonsillar mass and the lymph node were similar, showing effacement of normal architecture and extensive infiltration with diffuse sheets of neoplastic cells possessing plasmacytoid morphology with eccentric nuclei exhibiting "clock-faced" nuclear chromatin pattern that typically represent plasma cells. Binucleate and multinucleate forms were also present (Figure 2). The tonsillar lesion was fairly circumscribed and the epithelium was not infiltrated (Figure 3).
Further immunohistochemical analysis on the specimens showed CD138 plasma cell marker positivity (Figure 4), while CD20 and CD3 were negative, with kappa light chain restriction. This profile was in keeping with plasmacytoma. Serum protein electrophoresis showed the presence of monoclonal IgG kappa with normal levels of residual immunoglobulins. Skeletal survey, bone marrow biopsy, serum-free light chain, and urine analysis for Bence-Jones protein showed normal results. 
Six months after surgery the patient remained well. Repeat immunoglobulin assay at the 3-month postoperative review showed that the monoclonal IgG had returned to normal levels, with normal light chains and no evidence of multiple myeloma on bone marrow biopsy and no lytic lesions on skeletal survey. Repeat investigations at the 6-month mark remained negative.