Overview
Lymphomatoid papulosis (LyP) is a chronic, recurrent, self-resolving papulonecrotic or papulonodular skin disease that is part of the primary cutaneous CD30+ lymphoproliferative disease The primary CD30+ lymphoproliferative disease is a type of skin disease. Primary cutaneous CD30+ lymphoproliferative disease is the second most common type of cutaneous T-cell lymphoma, accounting for 25% of all cutaneous T-cell lymphomas. This group includes lymphomatoid papulosis at the benign end, primary cutaneous anaplastic large cell lymphoma (c-ALCL) at the malignant end, and their intermediate borderline types. c-ALCL and LyP have some clinical, pathologic, and immunophenotypic overlap, and both are histologically characterized by allogeneic CD30+ T cells, forming a spectrum of disease [1].
Epidemiology
Lymphomatoid papulosis can develop at any age and accounts for approximately 15% of cutaneous T-cell lymphomas, with an average age of onset of 35-45 years and an incidence ratio of approximately 1.5:1 between men and women [2].
Pathogenesis
The etiology of the disease is still unclear and has been suggested to be related to viral infections such as EBV and HTLV-1, but there has been no conclusive evidence to support this. mutations in the transforming growth factor-β receptor on the surface of CD30+ tumor cells are thought to be an important mechanism of tumor progression [3].
Clinical features
The typical lesions of lymphomatoid papulosis are brownish-red papules and nodules that may fade, necrotize and crust centrally, and the rash may spontaneously resolve in 3-8 weeks. The characteristic change is the coexistence of all phases of lesions with recurrent attacks. The papular nodules may be followed by hypopigmented or hyperpigmented patches and occasionally superficial atrophic scarring. The lesions may be limited in distribution or generalized and may range in number from a few to several hundred. There are usually no conscious symptoms.
The duration of the disease varies from a few months to several decades. About 20% of patients develop other types of cutaneous lymphoma before or after the onset of the disease or concurrently, most commonly mycosis fungoides, cutaneous mesenchymal large cell lymphoma, and Hodgkin’s disease. The prognosis is usually good, with approximately 4-10% of patients progressing to other types of lymphoma, and the risk factors for progression to other lymphomas are unknown.
Dermatopathological manifestations
The histopathologic changes of lymphomatoid papulosis are related to the period of time in which their lesions are present. Currently, its histological changes are classified into three types, type A, type B, and type C [4]. Newer studies have proposed the concept of type D lymphomatoid papulosis [5].
Type A lesions present as a wedge-shaped inflammatory infiltrate of predominantly small lymphocytes, neutrophils or eosinophils widely distributed in the dermis, interspersed with scattered or sheets of heterogeneous CD30+ large lymphocytes. The cells are sometimes multinucleated or R-S-like and represent a small percentage of the lesion, often <25%. There is moderate epidermal hypertrophy and hyperkeratosis of the epidermis, often with lymphocytic pro-epidermis.
Type B lesion changes are less common, accounting for less than 10% of the lesions. They are characterized by myxoid granuloma-like pathological changes. A lymphocyte-dominated perivascular banding infiltration of the dermal papillae is associated with lymphocytophilic epidermolysis. Anisocytic cells may be seen, but tumor cells often do not express CD30.
Type C lesions show a single or clustered CD30+ large lymphocytic infiltrate (> 75%) in the dermis with a mixed inflammatory cell infiltrate that wants to recede to a lesser extent. This type is similar to the histological presentation of mesenchymal large cell lymphoma.
Type D is a newly proposed type with infiltrating cells characterized by CD8+ large lymphocytes with a pro-epidermal nature. It needs to be distinguished from the histological changes of primary aggressive cutaneous CD8+ cytotoxic T-cell lymphoma [5].
Diagnosis and differential diagnosis
The diagnosis of lymphomatoid papulosis relies on a combination of clinical and pathological findings. Histologically its often indistinguishable from cutaneous mesenchymal large cell lymphoma, so clinical diagnosis is important. The disease often manifests clinically as polymorphic lesions, so it needs to be differentiated from mossy furunculosis, insect bite dermatitis, and folliculitis [6].
Treatment
There are no satisfactory control methods for lymphomatoid papulosis, and it is generally necessary to choose treatments with less toxic side effects, taking into account the patient’s general condition and prognosis. For example, interferon injections, low-dose methotrexate, topical nitrogen mustard, and whole-body ultraviolet phototherapy. It is important to note that patients need long-term follow-up because of the possibility of developing lymphoma [6].
References
[1] Kempf W, Pfaltz K, Vermeer MH, Cozzio A,Ortiz-Romero PL, Bagot M, et al. European Organization for Research and Treatment of Cancer (EORTC), International Society of Cutaneous Lymphoma (ISCL) and United States Cutaneous Lymphoma Consortium (USCLC) consensus recommendations for the treatment of primary cutaneous CD30-positive lymphoproliferative disorders: lymphomatoid papulosis and primary cutaneous anaplastic large-cell lymphoma. lymphoma. blood. 2011.
[2] Willemze R, Jaffe ES, Burg G, Cerroni L, Berti E, Swerdlow SH, et al. WHO-EORTC classification for cutaneous lymphomas. Blood. 2005;105:3768-85.
[3] Kadin ME. Pathobiology of CD30+ cutaneous T-cell lymphomas. J Cutan Pathol. 2006;33 Suppl 1:10-7.
[4] Kempf W. CD30+ lymphoproliferative disorders: histopathology, differential diagnosis, new variants, and simulators. J Cutan Pathol. 2006;33 Suppl 1:58-70.
[5] Saggini A, Gulia A,Argenyi Z, Fink-Puches R, Lissia A, Magana M, et al. A variant of lymphomatoid papulosis simulating primary cutaneous aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma. description of 9 cases. am J Surg Pathol. 2010;34:1168-75.
[6] Zhu X.J., Wang B.X., Sun J.F., and Xiang L.H., eds. Dermatology January 2011, First Edition; Peking University Medical Press.