[Diffuse plane normolipemic xanthomatosis and necrobiotic xanthogranuloma associated with monoclonal gammopathy--determining the disease stage with PET-CT and treatment experience. Two case studies and literature review].Vnitr Lek. 2010 Nov; 56(11):1158-68.VL
Monoclonal gammopathy may manifest itself through a range of skin disorders, including plane normolipemic xanthoma and necrobiotic xanthogranuloma. The present paper describes two patients with these cutaneous symptoms. The first has extensive areas of skin affected by flat xanthomas, monoclonal gammopathy with > 10% infiltration of bone marrow with clonal plasmocytes and, according to PET-CT, unclear lymphadenopathy in the retroperitoneal area. The size of this lymphadenopathy (histologically no malignant infiltration and no confirmed infectious aetiology) has not changed significantly over a 4-year follow-up. Repeated PET-CT scans showed decrease in SUV value in this infiltration from 7.5 to 3.8. Four cycles of treatment with a combination of bortezomib, cyclophosphamide and dexamethasone brought neither reduction in monoclonal immunoglobulin nor change to skin morphology. We believe that the abdominal lymphadenopathy is associated with xanthomatosis but have been unable to confirm this unequivocally. The second patient is being followed up for more than 10 years, originally for MGUS, later for asymptomatic multiple myeloma. Last year, painful subcutaneous and cutaneous infiltrates, isolated on an upper limb and more frequent on lower limb, started to occur. These infiltrates are palpable. PET-CT imaging provided an excellent depiction of these infiltrates, showing no pathology on the head, chest and abdomen and no osteolytic foci on the skeleton. CT imaging showed clearly numerous infiltrates in the skin and subcutaneous tissue of lower limbs, particularly both shanks, reaching up to 2 cm in depth. The largest infiltrate, measuring 3.5 by 2 by 10 cm, was identified in the distal dorsal part of the right shank. PET imaging of lower limbs showed distinctly pathological accumulation in all infiltrates described above; the accumulation of glucose in the lower part of the right shank reached 10.0 SUV. CT images of lower limbs showed increased density saturated hypodermis even in the areas where there is no increased accumulation of 18 fluoroglucose. Following 40 Gy irradiation, the size of infiltrate in the radiated area decreased and their soreness ceased.
PET-CT imaging offered information on extra-cutaneous signs of plane normolipemic xanthomas and provided excellent depiction of the areas of the skin and hypodermis affected by necrobiotic xanthogranuloma. Chemotherapy with cyclophosphamide, bortezomib and dexamethasone brought no reduction in monoclonal immunoglobulin concentration, and no reduction in plane normolipemic xanthomas. Radiotherapy targeted at large foci of xanthogranulomas led to partial regression and ceased infiltrate soreness.