Dermoscopy Pattern, Histopathology and Immunophenotype of Primary Cutaneous B-Cell Lymphoma Presenting as a Solitary Skin Nodule.

IMPORTANCE: To date, no dermoscopic features have been described for the diagnosis of primary cutaneous B-cell lymphoma (PCBCL). This tool might be helpful for the clinical differential diagnosis in the context of single erythematous nodules of the skin. OBSERVATIONS: Ten cases of PCBCL, presenting clinically as solitary red/pinkish nodules, were retrospectively retrieved. Patient data were collected along with dermoscopic and histopathological features of each lesion. Most lesions (9/10) showed white circles with a salmon-colored background/area (6 lesions), scales (7 lesions), arborizing vessels (5 lesions) or a polymorphous vascular pattern (2 lesions). Histology revealed a cutaneous marginal zone lymphoma in 6 lesions, a follicle center lymphoma in 2 lesions and a diffuse large B-cell lymphoma in 2 lesions. CONCLUSIONS AND RELEVANCE: Dermoscopic examination may be helpful for improving the clinical recognition of PCBCL although skin biopsy remains mandatory.