Case Reports
A 67-year-old Japanese man was referred to our department with numerous
papules and nodules on the trunk and extremities, without any subjective
symptoms (Fig. 1a ). The patient did not experience fever,
hepatosplenomegaly, or systemic lymphadenopathy. The complete blood cell
count indicated mild anemia and no atypical lymphocyte in the peripheral
blood. A biochemical blood test revealed a high β2-microglobulin level
of 4.2 mg/L (normal range: 0.8 to 1.8) and high immunoglobulin M level
of 2,928 mg/dL (33 to 190), represented as a monoclonal peak by
electrophoresis. The examination also disclosed mild abnormalities of
the coagulation/fibrinolysis system including factor X, 40% (70 to
130); fibrin/fibrinogen degradation products, 9 μg/mL (0 to 5); and
plasmin-α2 plasmin inhibitor complex, 2.8 μg/mL (0 to 0.8). Flow
cytometric analysis of bone marrow showed T-cell dominants.
Histopathological examination of the skin revealed an amorphous
substance around vessels in the dermis and subcutis (Fig. 1b and
1c ), which was highlighted in an orange color (Fig. 1d ) and
apple-green-birefringence (Fig. 1e ) by direct fast scarlet
staining and polarization, respectively. Histopathological examination
of the bone marrow revealed mild proliferation of lymphocytes,
plasmacytes, and lymphoplasma cells with Dutcher’s bodies without atypia
(Fig. 1f and 1g ), and the presence of CD20-positive cells
(Fig. 1h ). A diagnosis of AL amyloidosis due to WM was made.