Lymphomatoid Papulosis Histopathologically Simulating Angiocentric and Cytotoxic T-cell Lymphoma

Etiopathogenesis, Diagnosis, and Treatment Strategies for Lymphomatoid Papulosis with Particular Emphasis on the Role of the Immune System

Lymphomatoid papulosis (LyP) is a very rare disease that belongs to the group of CD30+ lymphoproliferative skin diseases. LyP is localized or generalized and usually presents as isolated or clustered red/brown-red lesions in the form of nodules and/or papules. The course of the disease is in most cases mild; however, depending on concomitant risk factors and history, it may progress to lymphoma, significantly reducing the survival rate and prognosis. Importantly, the clinical picture of the disease remains somewhat ambiguous, leading to a large number of misdiagnoses that result in inappropriate treatment, which is usually insufficient to alleviate symptoms. In addition to clinical manifestations, the histological characteristics vary widely and usually overlap with other conditions, especially those belonging to the group of lymphoproliferative disorders. Although diagnosis remains a challenge, several recommendations and guidelines have been introduced to standardize and facilitate the diagnostic process. This article reviews the available literature on the most important aspects of etiopathogenesis, clinical and histopathological features, diagnostic criteria, and possible treatment strategies for LyP, with particular emphasis on the role of the immune system.

Gamma/Delta Phenotype in Primary Cutaneous T-cell Lymphomas and Lymphoid Proliferations: Challenges for Diagnosis and Classification

Primary cutaneous T-cell lymphomas pose a diagnostic challenge for dermatopathologists, hematopathologists, and general surgical pathologists. Recognition of gamma/delta phenotype in cutaneous T proliferations has been enhanced by the availability of antibodies against TCRgamma and delta for immunohistochemistry. Thus, reporting gamma/delta phenotype in a cutaneous T-cell lymphoid proliferation may indicate a significant change in therapy and a challenge for dermatologists and oncologists who treat these patients. Herein, we discuss primary cutaneous gamma/delta T-cell lymphoma, its differential diagnosis, and other skin lymphoid proliferations that may show gamma/delta phenotype. Awareness of the occurrence of gamma/delta phenotype in both T-cell lymphomas and benign lymphoid proliferations involving skin is crucial for a better interpretation of histopathologic findings. Integration of clinical presentation, morphology, immunoprofile, and molecular findings is key for a correct diagnosis and appropriate therapy of lesions displaying gamma/delta T-cell phenotype.

A case of lymphomatoid papulosis type E in a young adult: An uncommon entity

Lymphomatoid papulosis (LyP) type E is a rare variant of the primary cutaneous CD30+ lymphoproliferative disorders, characterized clinically by large necrotic eschar-like lesions and histopathologically by angiodestructive and angioinvasive infiltrates of CD30+ lymphocytes. As in other forms of lymphomatoid papulosis, type E lesions may undergo spontaneous regression after weeks, with frequent recurrences. We report a 21-year old male with an angiodestructive infiltrate of CD30+ lymphocytes manifesting as a papular eruption rather than ulceration, and suggest that this clinical phenotype might be related to the presence of CD4+ lymphocytes in the inflammatory cell infiltrate.

An unusual case of lymphomatoid papulosis type E with extensive necrosis

Lymphomatoid papulosis type E (LyP) is a recently described subtype of LyP characterized by an angioinvasive infiltrate of atypical lymphocytes expressing CD30. We present a case of type E LyP with extensive cutaneous necrosis in the histopathological evaluation which was misdiagnosed as an ulcerative form of bacterial skin infection. The remarkable cutaneous necrosis showed in our case might be related to the angiodestructive infiltrate that was present in this circumstance.

Lymphomatoid Papulosis Type D: Report of a Case in a Child and Review of the Literature

Lymphomatoid papulosis (LyP) is a cutaneous CD30-positive T-cell lymphoproliferative disorder that occurs primarily in adults and presents with crops of papules that become necrotic and spontaneously regress. It is classified according to the histopathologic findings; currently recognized subtypes include A, B, C, D, and E. LyP is uncommon in children. Herein we describe a child with an unusual clinical presentation of LyP type D and review the literature of reported cases in children.

Immunocytochemistry and the diagnosis of cutaneous lymphoma

Cutaneous lymphoid infiltrates may pose some of the most difficult diagnostic problems in dermatopathology. Immunocytochemistry is often employed in an effort to determine whether an infiltrate is neoplastic or, in the case of clearly malignant infiltrates, to provide a specific diagnosis. The rarity of these disorders and the variant immunocytochemical profiles they may present further thwart understanding and sometimes prevent an accurate diagnosis. In this review the common immunocytochemical profiles of various cutaneous lymphomas are presented and potential pitfalls and problems considered. Immunocytochemistry is not a diagnostic test but, as in other areas of histopathology, is a highly valuable tool that requires critical interpretation within a context: so applied, it is an indispensable part of the pathologist's arsenal in evaluating lymphoid infiltrates and defining different lymphomas.

[Clinical course and therapy of lymphomatoid papulosis. Experience with 17 cases and literature review]

Lymphomatoid papulosis is a rare disease with a worldwide incidence of 1.2 to 1.9 per 1 million. It affects all age groups with a peak incidence between 30 and 40 years and an apparent male predominance. Occurrence in childhood has also been described. Both the etiology and pathogenesis of the disease are unknown. The clinical presentation is extremely variable and frequently uncharacteristic. A papulonodular eruption, characterized by self-healing skin lesions appearing in crops can often be seen, particularly on extremities. We report on 17 patients, including 2 children. By detailing 6 cases we point out the variable morphologic manifestations, the different courses of disease and therapeutic options.

Three cases of lymphomatoid papulosis with a CD56+ immunophenotype

We report 3 cases of lymphomatoid papulosis (LyP) with a CD56+, cytotoxic immunophenotype. All 3 patients presented with clinical histories typical of LyP, with one patient having associated mycosis fungoides. Histologically, two cases were type A LyP and one was type B. All 3 cases demonstrated a T-cell receptor clone in lesional skin without evidence of blood involvement. The atypical lymphocytes in each of the 3 cases expressed cytotoxic granules (T-cell intracellular antigen-1+ and granzyme B+) and were CD8+ and CD56+. Expression of CD56 is associated with a poor prognosis in subcutaneous panniculitis-like T-cell lymphoma and blastic natural killer cell lymphoma. However, the two cases of CD56+ LyP previously reported and the 3 cases in this series all appear to be pursuing an indolent course with no evidence of systemic disease.

CD30+ lymphoproliferative disorders: histopathology, differential diagnosis, new variants, and simulators

CD30+ lymphoproliferative disorders of the skin (CD30+ LPD) represent a well-defined spectrum of primary cutaneous T-cell lymphomas which have been recognized as distinct entities in recent lymphoma classifications. Lymphomatoid papulosis and anaplastic large-cell lymphoma share the expression of CD30 antigen as a common phenotypic hallmark but differ in regard to their clinical and histologic features as well as their biologic behavior. This article summarizes the histologic features of CD30+ LPD and presents recently identified new clinicopathologic variants of CD30+ LPD. There is an increasing number of reactive inflammatory disorders and neoplastic diseases which are composed of or contain a significant number of CD30+ cells and mimic LyP or anaplastic large cell lymphoma clinically or histologically. Differential diagnostic considerations focus on other lymphoproliferative processes with CD30+ tumor cells as well as non-lymphoid neoplasms and inflammatory simulators. The term CD30+ pseudolymphoma is proposed to designate inflammatory processes with CD30+ T cells. The final diagnosis of CD30+ LPD is based on a synthesis of clinical, histologic, phenotypic, and molecular genetic findings.