Table of Contents
Lymphomatoid papulosis-Low magnification
LEGEND
Lymphomatoid papulosis is a primary cutaneous low-grade T-cell lymphoma composed of large CD30+ cells (i.e., more than 4× the size of a normal lymphocyte).
There are several histologic subtypes, from type A to F. Type A accounts for >75% of cases. The subtypes are histopathologically relevant but have no clinical impact.
Type A typically has an inverted triangle (“wedge shape”) appearance.
Mixed inflammation with occasional presence of normal lymphocytes, neutrophils, and eosinophils.
Dermal nodular infiltrate of large atypical CD30+ T lymphocytes (i.e., >4× the size of a normal lymphocyte), with occasional epidermotropism.
Epidermal necrosis or ulceration may sometimes be observed, with epidermal hyperplasia (especially in type E, shown here).
Lymphomatoid papulosis-High magnification
LEGEND
Atypical mitoses may be observed
The epidermis is often reactive: presence of acanthosis and spongiosis, as well as papillary dermal edema (unlike in classic MF).
Epidermotropism
Lymphomatoid papulosis-Type C-Low magnification
LEGEND
Diffuse proliferation in the dermis of large atypical CD30+ T lymphocytes
Lymphomatoid papulosis-Type C-High magnification
LEGEND
Presence of large atypical CD30+ T lymphocytes, i.e., >4× the size of a normal lymphocyte
Lymphomatoid papulosis-Type C
CD3 may be positive or negative
In this case, CD3 expression is positive.
Lymphomatoid papulosis-Type C
ALK1 negative (marker of systemic anaplastic large cell lymphoma)
Lymphomatoid papulosis-Type C
EMA negative (marker for systemic anaplastic large cell lymphoma)
Lymphomatoid papulosis-Type E
LEGEND
Type E is characterized by angioinvasion, angiodestruction, and vascular occlusion, sometimes with presence of thrombi.
Epidermal ulceration and necrosis is extensive
Large CD30+ T lymphocytes are seen in the infiltrate.
Infiltrate of atypical lymphocytes
Lymphomatoid papulosis-Type E
CD3 may be positive or negative.
In this case, CD3 expression is positive.
Lymphomatoid papulosis-Type E
CD20 is negative in the dermal infiltrate.
A slight reactive positivity is seen at the site of ulceration.
Lymphomatoid papulosis-Type E
CD30 expression is positive (large cells) in the dermal infiltrate around the ulceration.
CD30 is typically negative in type B.
Lymphomatoid papulosis-Type E
ALK1 negative (marker for systemic anaplastic large cell lymphoma)
