PMC6875407_01
Physical examination revealed a pink nodule (with a 4 mm punch biopsy defect) on his chin and a pink plaque on his left cheek. Similar plaques and papules were evident on his upper trunk and scalp.
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fig1
Dermatology was consulted regarding asymptomatic erythematous papules, plaques, and nodules involving his upper trunk, face, and scalp that had abruptly appeared over the prior three weeks (Figure 1).
(a) Haematoxylin and Eosin stained tissue section from the chin punch biopsy. Atypical plasma cells with a Dutcher body apparent in the middle left (400 magnification; 40x). (b) CD138 positive (400 magnification, 40x). (c) CD45 positive (400 magnification, 40x). (d) Kappa light chain negative (40 magnification, 4x). (e) Lambda light chain positive (40 magnification, 4x).
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fig2
Punch biopsies from the chin nodule and a scalp plaque were obtained (Figure 2(a)). The papillary and reticular dermis were replete with atypical plasma cells, focally resembling plasmablasts, positive for CD138 (Figure 2(b)) and CD45 (Figure 2(c)) by immunohistochemistry. In situ hybridization (ISH) confirmed lambda light chain restriction (Figures 2(d) and 2(e)).