Primary cutaneous lymphoplasmacytic lymphoma-like B-cell neoplasm with features of acute inflammation and epidermal atypical cells

Abstract

Primary cutaneous lymphoplasmacytic lymphoma (LPL) is rare. The author herein reports a case of LPL-like B-cell neoplasm with acute inflammation and epidermal cell atypia. A 69-year-old man presented skin ulcer of neck. The lesion appeared granulation tissue with surface fibrin deposition; an inflammatory process was suggested. Peripheral blood data showed no abnormalities, including the segments of leukocytes. No plasmacytosis was seen. No M-proteins, macroglubulins, or cryoglobulins were noted in serum and urine. The clinical diagnosis was non-specific skin ulcer. A wide biopsy was taken. It showed a destructive proliferation of atypical small lymphocytes, atypical plasmacytoid lymphocytes, and atypical plasma cells in dermis and subcutaneous tissue. The biopsy also showed acute inflammatory features; foci of many neutrophils were scattered in neoplastic cells. Some of them showed microabscesses. In addition, foci of atypical squamous cells were seen in the epidermis. Immunohsitochemically, the tumor cell showed B-cell lineage. The tumor cells were diffusely positive for vimentin, CD45, CD20, CD79, bcl-2, CD38, and CD138. The tumor cells were only focally positive for CD3 and CD45RO. A few tumor cells were positive for CD30, CD56, and CD10. Some of the tumor cells were positive for p53 and Ki-67 antigen (labeling index = 35%). The tumor cells were negative for pancytokeratin AE1/3, pancytokeratin CAM5.2, CD5, CD23, CD43, and cyclinD1. The tumor cells were positive for κ-chain but negative for λ-chain, indicating that the tumor cells have plasmacytic characteristics and that there was a light chain restriction which indicates monoclonal nature of the tumor plasma cells. The tumor cells were negative for Epstein-Barr virus (EBV) associated molecules such as EBV latent membrane protein-1 (LMP-1) and EBV early RNAs (EBER). A pathological diagnosis made by the author was cutaneous LPL-like B-cell malignant tumor. The author thought that this tumor could not be definitely diagnosed a primary cutaneous LPL, because other small-sized B-cell lymphomas with plasmacytoid differentiaton could not be excluded. The current tumor was also characterized by acute inflammatory features and epidermal squamous cell atypia suggestive of squamous cell carcinoma. Imaging modalities including CT identified no other tumors and lymphoadenopathy in the body. The systemic bones were free of myeloma features. No bone marrow study was performed after the pathological diagnosis. The tumor cured and the patient discharged from the hospital 3 months after the first presentation.