Dermal lymphoplasmacytic/lymphoplasmacytoid lymphoma (immunocytoma) in a 40-year-old man

The skin may be the site of origin of a lymphomatous process or it may be secondarily involved as a systemic manifestation of a lymphoma arising in an extradermal (extracutaneous) site. Dermal lymphomas are difficult to recognize and differentiate from non-specific chronic dermatitis. Several histologic features have been proposed to help in differentiating between benign and malignant lymphoid dermal infiltrates. However, this distinction has been difficult to reproduce consistently. With use of immunologic techniques applied to fresh or paraffin-embedded material, the differentiation between a benign or malignant dermal cell process has been dramatically improved.