Giant cell arteritis mimicking multiple myeloma; diagnosed by PET scan.

Abstract: This case report describes a patient who presented with severe anemia, monoclonal gammopathy, a high erythrocyte sedimentation rate and significant weight loss. These features were highly suggestive of multiple myeloma. Bone marrow aspiration was negative for myeloma on two occasions. A positron emission tomography (PET) scan showed extensive 2-flourodeoxy-glucose uptake in the vascular tree consistent with arteritis. A temporal artery biopsy established the diagnosis of giant cell arteritis (GCA). There were no typical symptoms of GCA, such as headache, visual disturbance, or polymyalgia rheumatica. The patient was treated with steroids, which resulted in the resolution of anemia, monoclonal gammapathy, and other symptoms.

Key Words: giant cell arteritis, multiple myeloma, monoclonal gammapathy, PET scan, anemia

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Giant cell arteritis (GCA) is a systemic vasculitis that usually presents with headache, scalp tenderness, visual disturbances, weight loss, and a very high erythrocyte sedimentation rate. (1) Diagnosis is usually established by temporal artery biopsy. PET scan has been used in the diagnosis and for the follow up of the treatment of giant cell arteritis. (2) Our patient presented with rather severe anemia, significant weight loss, and monoclonal gammapathy. She did not have typical symptoms of giant cell arteritis, such as headache or visual problems. These features were highly suspicious for myeloma. PET scan incidentally revealed findings consistent with arteritis, which was then confirmed by temporal artery biopsy.

Case Report

A 78-year-old lady presented with the complaints of loss of appetite, fever, fatigue and weight loss of about 15 pounds. These symptoms started 3 months before presentation. She denied fever, chills, night sweats, headache or visual problems. Review of system was otherwise unremarkable. The patient had a history of diabetes, hypertension, hypercholesterolemia, and hypothyroidism. She did not drink alcohol nor did she smoke. Physical examination revealed a pale, elderly female but failed to reveal findings suggestive of malignancy, vasculitis, infection or other acute systemic disease. Laboratory workup showed hemoglobin of 8.9 g/dL, MCV 77 FL, Platelets 494 K/uL, and normal white cell count. Liver and kidney function tests were within normal limits. Serum iron was 18 [micro]g/dL, total iron binding capacity was 232 [micro]g/dL, saturation 8%, and ferritin 1408 ng/mL. Peripheral blood smear was rather unrevealing. Serum protein electrophoresis showed an "M" spike in the gamma region with a concentration of 0.47 g/dL. Immunofixation identified this as IgG-Kappa. UPEP and Urine immunofixation were unremarkable. IgG was elevated at 2303 mg/dL; IgA and IgM were normal. ESR was 89 mm/h.

Bone marrow aspiration and biopsy was performed because of the suspicion for myeloma, which showed normocelluar marrow with no evidence of myeloma. Upon patient's persistence, a whole body positron emission tomogram was done to rule out occult malignancy, which showed diffuse FDG uptake in carotid, subclavian arteries and thoracic aorta, suggesting arteritis (Fig. 1). A temporal artery biopsy revealed giant cell arteritis (Fig. 2). Treatment with steroids resulted in the resolution of anemia, monoclonal gammapathy, and weight loss.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Discussion

Giant cell arteritis is a chronic vasculitis of medium and large size vessels that most commonly affects individuals over 50 years of age. (3) It most frequently involves the cranial branches of the arteries originating from the aortic arch. (4) Common manifestations include fever, weight loss, headache, visual disturbances, jaw claudication, etc. (5) Our patient did not have these features except for weight loss.

Elevated sedimentation rate, normochromic anemia, thrombocytosis, and increased alkaline phosphatase are some of the laboratory abnormalities in GCA. (6) Monoclonal gam-mopathy (MGUS) may be present in rheumatologic conditions, such as Sjogren syndrome, rheumatoid arthritis, and systemic lupus erythematosus. (7) However, an association between GCA and MGUS is not well described in the literature. Interestingly, monoclonal protein disappeared after the treatment with steroids in our patient.

The diagnosis of GCA is typically established by temporal artery biopsy. In this patient, a PET scan incidentally discovered it, which was then proven by biopsy. The utility of PET scan in GCA has been described in the literature, especially for the follow-up of treatment. FDG uptake in vascular tree was seen in as many as 83% of patients with GCA. (2,8)

Conclusion

Giant cell arteritis may present with atypical manifestations, such as monoclonal gammopathy and significant anemia, and may mimic multiple myeloma. This case also describes the "incidental" discovery of GCA by PET scan. Awareness of GCA's unusual presentation and timely treatment can prevent significant morbidity.

Acknowledgment

We are indebted to Paul Gibbs, MD, and Peter Sze, MD, for their support.

References

1. Gonzalez-Gay MA, Barros S, Lopez-Diaz MJ, et al. Giant cell arteritis: disease patterns of clinical presentation in a series of 240 patients. Medicine (Baltimore) 2005;84:269-276.

2. de Leeuw K, Bijl M, Jager PL, Additional value of positron emission tomography in diagnosis and follow-up of patients with large vessel vasculitides. Clin Exp Rheumatol 2004;22(6 Suppl 36):S21-S26.

3. Hunder GG. Giant cell arteritis and polymyalgia rheumatica. In: Textbook of Rheumatology. 6th edition. Philadelphia, WB Saunders Company, 2001.

4. Klein RG, Hunder GG, Stanson AW, et al. Large artery involvement in giant (temporal) arteritis. Ann Intern Med 1975;83:806-812.

5. Gabriel SE, O'Fallon WM, Achkar A, et al. The use of clinical characteristics to predict the results of temporal artery biopsy among patients with suspected giant cell artertitis. J Rheumatol 1995;22:93-96.

6. Gonzalez-Gay MA, Lopez-Diaz MJ, Barros S, et al. Giant cell arteritis: laboratory tests at the time of diagnosis in a series of 240 patients. Medicine (Baltimore) 2005;84:277-290.

7. Broggini M, Cavallo A, Baratelli E, et al. Monoclonal gammapathy of uncertain significance in rheumatic disease. Recenti Prog Med 1990;81:306-309.

8. Blockman D, de Ceuninck L, Vanderschueren S. et al. Repetitive 18F-fluorodeoxyglucose positron emission tomography in giant cell arteritis: a prospective study of 35 patients. Arthritis Rheum 2006;55:131-137.

Satheesh K. Kathula, MD, FACP, Joseph Mantil, MD, PhD, Timothy Drehmer, MD, FACP, and Soma S. Patil, MD

From Greater Dayton Cancer Center and Department of Internal Medicine, Wright State University, Dayton, OH.

Reprint requests to Satheesh K. Kathula, MD, FACP, 1062 Kenworthy Place, Centerville, OH 45458. Email: [e-mail]

Accepted June 27, 2006.

RELATED ARTICLE: Key Points

* Giant cell arteritis may present with significant anemia, weight loss, high ESR, and monoclonal gammapathy and can mimic myeloma.

* Typical manifestations of GCA may be absent.

* PET scan may be used in the management of giant cell arteritis, but it does not replace the temporal artery biopsy for diagnosis.

* Treatment with steroids can result in the resolution anemia, monoclonal gammapathy, etc.