Figure 1.

Histological features of primary cutaneous anaplastic large cell lymphoma (pcALCL). (A) This skin punch biopsy is characterized by a dense lymphoid population filling the dermis, without significant epidermotropism. The epidermis shows secondary changes, including hyperkeratosis and papillomatosis (Hematoxylin and eosin (H&E), 2.4×). Inset: the neoplastic population is composed of large-sized cells with abundant, slightly eosinophilic cytoplasm and roundish, atypical nuclei. Two mitotic figures are evident in the center of the field. Some neutrophils and eosinophils are scattered in the context of the neoplastic population (H&E, 20×). The large cells are positive for CD3 (B), CD4 (C), and CD30 (D) immunohistochemical staining.