Postgrad Med J (1990) 66, 477 - 478 i) The Fellowship of Postgraduate Medicine, 1990 Postgrad Med J: first published as 10.1136/pgmj.66.776.477 on 1 June 1990. Downloaded from

Primary plasmacytoma ofthe thyroid S. Cheslyn-Curtisl* and A.B. Akosa2t Departments of'Surgery and2Histopathology, Wexham Park Hospital, Slough, Berkshire SL2 4HL, UK.

Summary: Primary plasmacytoma of the thyroid is a very rare tumour. We report a case and emphasize the importance of excluding multiple myeloma which may present as an extrameduliary plasmacytoma. Histological diagnosis has been simplified by the use ofimmunohistochemical techniques.

Introduction Extra-medullary primary plasmacytomas are plasma cells (Figure 1). Immature and atypical uncommon and their occurrence in the thyroid is forms of plasma cells were infrequent and mitoses rare."2 Only two cases have been reported from rare. There were some residual thyroid follicles Britain.3 Histological diagnosis has been made with marked lymphocytic infiltration suggestive of much easier by the demonstration of a monotypic an underlying chronic thyroiditis. population of plasma cells, using immunohisto- Immunohistochemistry was performed using the chemical techniques. However, its presence as an unlabelled antibody (PAP) immunoperoxidase early manifestation of multiple myeloma must be method with trypsinization for immunoglobulins excluded. A primary plasmacytoma of the thyroid (IgG, IgM and IgA) and for light chains (kappa is described supported by immunohistochemical and lambda). Plasma cells showed a striking intra- and ultrastructural examination. The presentation cytoplasmic staining for IgG and kappa light and management of these tumours is discussed. chains in both the thyroid and lymph node tissue. copyright. Staining for lambda light chains, IgM and IgA was negative. Electron microscopy confirmed the neo- Case report plastic features of the plasma cells, including well developed and stacked rough endoplasmic reti- A 78 year old woman presented with a 6-month culum and numerous mitochondria. These are the history ofa swelling in the left side ofher neck. Her features of a plasmacytoma. only symptom was mild dysphagia. Physical Further investigations were performed to deter-

examination revealed a firm, smooth, non-tender, mine whether the tumour was solitary or a manifes- http://pmj.bmj.com/ mobile enlargement of the left lobe of the thyroid tation of multiple myeloma. The serum protein with deviation of the trachea. Thyroid function, level was 82 g/l with an albumin/globulin ratio of haemoglobin, serum proteins and electrolytes were 1.1:1 and a normal immunoglobulin profile. Pro- normal. Chest X-ray showed marked tracheal tein electrophoresis showed a broad atypical band displacement and an ultrasound scan confirmed the presence of a solid mass in the left lobe of the thyroid.

At operation, a well encapsulated tumour mass on September 24, 2021 by guest. Protected (8 cm x 4 cm x 3 cm) was found in association with enlarged lymph nodes lying both anterior to the gland and also within the left deep cervical chain. A left thyroid lobectomy with lymph node biopsy was performed. Light microscopy showed thyroid and lymph node tissue diffusely infiltrated by sheets ofmature

Correspondence: Miss S. Cheslyn-Curtis, M.S., F.R.C.S., Department of Gastroenterology, The Middlesex Hospital, London WIN 8AA, UK. Present addresses: *The Middlesex/University College Hospitals, London, and tHammersmith Hospital, London, UK. Figure 1 Sheets of mature plasma cells with residual Accepted: 29 January 1990 thyroid follicles containing colloid. Low power x 80. 478 CLINICAL REPORTS Postgrad Med J: first published as 10.1136/pgmj.66.776.477 on 1 June 1990. Downloaded from in the gamma region which was identified by Jones proteinuria which also reverted to normal immunoelectrophoresis as IgG kappa. Protein after treatment.7-9 Bone marrow examination was electrophoresis and immunoelectrophoresis re- normal in all cases. verted to normal within 4 months ofthe operation. The histological distinction of primary plasma- Bone marrow, skeletal survey and isotope bone cytoma from plasma cell granuloma is difficult.'0 scan were normal and Bence Jones protein Tissue immunostaining for immunoglobulins, by negative. the PAP technique, has simplified the diagnosis Treatment was completed by local irradiation since the demonstration ofa monotypic population with 4000 cGy to the thyroid region and adjacent of plasma cells establishes the neoplastic nature of lymph nodes. The patient is well 18 months later the lesion and correspondence with the immuno- with no evidence of local or distant recurrence. electrophoretic characterization of serum protein establishes the site ofproduction. Our case demon- strated a striking intracytoplasmic staining of IgG Discussion and kappa light chains in both the thyroid and lymph node tissue and corresponded with the Extra-medullary plasmacytoma occurs either as a serum immunoelectrophoretic finding of a raised manifestation of multiple myeloma or as a solitary IgG kappa protein. primary tumour. Oberkircher et al.4 found that Primary plasmacytomas ofthe thyroid appear to 17% (24 of 141) ofpatients with multiple myeloma have an excellent prognosis even when there is presented with extra-medullary tumours but the involvement of adjacent lymph nodes. Patients incidence ofthyroid involvement has been reported have been followed for a median of 3 years (range to be only 2.6% (7 of 272) among extra-medullary 1-23 years). There has been no mortality from plasmacytomas.5 Primary plasmacytoma of the recurrent disease and the two tumours that recur- thyroid is very rare. Hazard and Schildecker' found red responded well to further treatment with either two cases following 14,000 thyroid operations radiotherapy or chemotherapy."' Hemi- or total performed over a 22-year period and MacPherson thyroidectomy with regional lymph node biopsy is et al.2 discovered one among 870 thyroid tumours. the initial treatment of choice. Local irradiation is

A review of the 28 cases ofprimary plasmacytoma probably an advisable adjunct to surgery when the copyright. ofthe thyroid which have been reported has shown juxtathyroid lymph nodes are involved by tumour. that most patients present in the fifth to seventh Further surgical clearance of these lymph nodes decades and that there is no sex difference. may be considered, although radical block dissec- The diagnosis of primary plasmacytoma can be tions of the neck seem to be unnecessary because of made only after the exclusion ofmultiple myeloma. the excellent prognosis of the tumour despite Investigations should include pre- and post- lymph node involvement. The rarity of plasma- operative serum electrophoresis, bone marrow cytoma of the thyroid makes it difficult to deter- examination and a skeletal survey or bone scan. mine optimum management for these patients. http://pmj.bmj.com/ Preoperative serum electrophoresis demonstrated an M-protein in 11 cases which by immunoelectro- Acknowledgements phoresis has shown four, including our own, with IgG kappa chains.246 In all cases, serum proteins We would like to thank Mr S.E. Knight, Consultant reverted to normal within 2 to 9 months ofremoval Surgeon and Dr M.H. Ali, Consultant Histopathologist, of the tumour. Three of these patients had Bence for their permission to report this case. on September 24, 2021 by guest. Protected References

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