Abstract
Plasmocytosis circumorificialis (PC) is a rare inflammatory mucosal disease histologically characterized by dense plasma cell infiltrates. A 73-year-old woman presented with ulceration on the lower lip. She had been receiving cancer chemotherapy for plasma cell leukemia (IgG, κ type). The ulcer located on the center of the lower labial mucosa was 10 × 7 mm in size with an irregular shape. Biopsy was performed under a clinical diagnosis of leukemia cell infiltration. Histopathologically, inflammatory cell infiltration mainly comprising plasma cells was observed, but immunohistochemical analysis showed a mixture of κ chain-positive and λ chain -positive cells. The ulcer completely epithelialized after biopsy. Final diagnosis was PC of the lower lip.
