Localized lymphomatoid papulosis: Unilesional lymphomatoid papulosis, regional lymphomatoid papulosis, and persistent agmination of lymphomatoid papulosis

Regressing Papules on the Sole of the Foot: Answer

“…Infrequently, these lesions may be localized to an isolated anatomic site (as in this case), a single lesion, or, very rarely, a solitary group of lesions on a background of MF. 3 In most cases, LyP follows an indolent, benign course with complete self-regression of the lesions.…”

“…Histologically, LyP demonstrates considerable variability in morphology and degree of lymphoid atypia, frequently mimicking malignant lymphoma despite a benign clinical course. The World Health Organization‐European Organization for Research and Treatment of Cancer classification recognizes 6 histologic subtypes of LyP, types A-E and a new subtype defined by chromosomal rearrangement 1,3,4 .Type A features large atypical CD30 + cells in a primarily perivascular distribution with variable vascular injury, many neutrophils, eosinophils, and spongiform pustulation.Type B consists of small cerebriform lymphocytes negative for CD30 in an epidermotropic pattern, resembling MF.Type C is characterized by a malignant-appearing infiltrate with predominantly large atypical CD30 + cells, morphologically mimicking anaplastic large-cell lymphoma (ALCL).Type D consists of an epidermotropic infiltrate of CD8 + noncerebriform lymphocytes with variable angiodestruction, resembling primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma.Type E is an unusual variant that may consist of CD8 + , CD56 + , or double-negative T cells in an angiocentric pattern with angiodestruction, resembling an aggressive peripheral T-cell lymphoma.A newly introduced subtype is defined by chromosomal rearrangements of the DUSP22-IRF4 locus on 6p25.3. Histology shows small cerebriform T cells in the epidermis and larger transformed lymphocytes in the dermis, resembling transformed MF.…”

“…Infrequently, these lesions may be localized to an isolated anatomic site (as in this case), a single lesion, or, very rarely, a solitary group of lesions on a background of MF. 3 In most cases, LyP follows an indolent, benign course with complete selfregression of the lesions.Histologically, LyP demonstrates considerable variability in morphology and degree of lymphoid atypia, frequently mimicking malignant lymphoma despite a benign clinical course. The World Health Organization-European Organization for Research and Treatment of Cancer classification recognizes 6 histologic subtypes of LyP, types A-E and a new subtype defined by chromosomal rearrangement 1,3,4 .…”