Lymphomatoid papulosis: reappraisal of clinicopathologic presentation and classification into subtypes A, B, and C.

OBJECTIVES To analyze clinicopathologic features of lymphomatoid papulosis and delineate the characteristics of histopathologic variants (types A, B, and C). DESIGN Retrospective nonrandomized study. SETTING University-based dermatologic referral center. PATIENTS Eighty-five patients with lymphomatoid papulosis. Clinical data and 1 or more biopsy specimens were available for review in all cases. When possible, immunophenotypic and molecular analyses were carried out. RESULTS Of these patients, 78 presented only 1 histopathologic subtype of lymphomatoid papulosis (64 had type A, 3 had type B, and 11 had type C). The last 7 patients presented more than 1 subtype (1 had A and B, 5 had A and C, and 1 had A, B, and C). Two patients had regional lymphomatoid papulosis, an unusual clinical presentation characterized by groups of lesions localized to 1 anatomic region. We observed, we believe for the first time, that some histopathologic patterns, ie, follicular mucinosis (n = 1), syringotropic infiltrates (n = 1), epidermal vesicle formation (n = 2), and syringosquamous metaplasia (n = 1), were associated with lymphomatoid papulosis. A distribution along hair follicles, or follicular lymphomatoid papulosis, was observed in 5 biopsy specimens. A bandlike rather than a wedge distribution of the infiltrate was seen in 5 specimens from patients with lymphomatoid papulosis type A. Of 8 patients who had associated lymphoid malignancies, 4 had Hodgkin disease and 4 had mycosis fungoides. CONCLUSIONS Lymphomatoid papulosis is a cutaneous disorder with multiple clinicopathologic features. Differentiating between mycosis fungoides and anaplastic large cell lymphoma may be very difficult and sometimes impossible. In the spectrum of CD30(+) cutaneous lymphoproliferative disorders, boundaries between these 2 entities are not clear-cut.