Lymphomatoid Papulosis (LyP)

• Chronic papulonecrotic condition with self-healing nature; recurrent crops of lesions at different stages of development that spontaneously heal over 1–2 months on trunk and limbs, leaving oval slightly depressed scars
• Controversy over whether LyP is a benign disorder of activated T cells responding to internal/external stimuli or if indolent T-cell malignancy of skin; most likely low-grade malignant CTCL; chronic, indolent course in most patients and prognosis is usually excellent
• Presents as erythematous necrotic papules, papulopustules, necrotic eschars or papulovesicles
• Histology: wedge-shaped dense dermal infiltrate consisting of lymphoid cells with numerous neutrophils, eosinophils, and atypical lymphocytes (latter may be 50% of cells), ± epidermotropism, atypical T cells characteristically stain positive with CD30-positive (Ki-1)
• Treatment: no curative benefits; low dose weekly methotrexate, PUVA, high potency topical steroid (to hasten resolution of lesions), topical nitrogen mustard

Figure 5.12 A: CTCL, patch stage* B: CTCL, patch stage* C: CTCL, plaque stage* *Courtesy of Dr. Sophie M. Worobec

Figure 5.13 A: CTCL, tumor stage* B: Lymphomatoid papulosis* C: Lymphomatoid papulosis* *Courtesy of Dr. Sophie M. Worobec