Cutaneous Immunocytoma

Cutaneous Involvement of Angioimmunoblastic T-Cell Lymphoma Masquerading as B-Cell Reactive Lymphoid Hyperplasia

ABSTRACT

A 59-year-old woman presented with a persistent eruption manifested as multiple agminated miliary facial papules. Histopathological examination showed prominent nodular dermal lymphoid infiltrates with hyperplastic follicles that were initially interpreted as B-cell reactive lymphoid hyperplasia. Several years later, an additional biopsy showed a dense perifollicular infiltrate with reactive primary and secondary follicles. Accompanying T cells corresponded to CD3/CD4/PD1/CXCL13-positive cells and scattered Epstein-Barr virus-positive B cells were identified by in situ hybridization. A monoclonal T-cell population was demonstrated by TCRγ and TCRβ Polymerase Chain Reaction amplification, as well as a minor abnormal circulating T-cell population by flow cytometry (0.62% of the white blood cells, CD4+CD3s-CD7-). A biopsy specimen from an enlarged right supraclavicular lymph node disclosed nodal involvement by angioimmunoblastic T-cell lymphoma. The observation of B-cell dermal nodular infiltrates with well-demarcated lymphoid aggregates forming primary lymphoid follicles may lead to overlook the T-cell component in some cases of angioimmunoblastic T-cell lymphoma. In such cases, a careful assessment of the apparently minor T-cell component is important to establish a correct diagnosis.

Kappa and lambda immunohistochemistry and in situ hybridization in the evaluation of atypical cutaneous lymphoid infiltrates

BACKGROUND

Atypical cutaneous lymphoid infiltrates are challenging lesions in dermatopathology. We present a summary of the literature regarding kappa and lambda immunohistochemistry (IHC) and in situ hybridization (ISH) in the evaluation of atypical cutaneous or mucosal lymphoid infiltrates.

METHODS

Relevant articles from 1967 to 2018 in the English language were identified and summarized. In the absence of larger studies, case series of n ≥ 3 were included.

RESULTS

Sixty-three articles assessing kappa and lambda IHC and/or ISH were identified. Most focused on marginal zone lymphomas. Other lymphomas included follicle center lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma, plasmablastic lymphoma, multiple myeloma, monoclonal gammopathy of undetermined significance, and polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS). Non-neoplastic lesions included reactive lymphoid hyperplasia, cutaneous plasmacytosis, connective tissue disease, IgG4-related disease, acrodermatitis chronic atrophicans, Zoon balanitis, dermatitides, and infiltrates around epithelial dysplasias/neoplasias.

CONCLUSION

Kappa and lambda IHC and ISH are useful tools in the evaluation of cutaneous B-cell lymphomas and plasma cell neoplasms. The literature supports that the detection of light-chain restriction by IHC and ISH is one of the most useful findings in the differential diagnosis of reactive lymphoid hyperplasia vs B-cell lymphoma with plasmacytic differentiation.

Primary Cutaneous B-Cell Lymphomas

B-cell lymphomas occurring in the skin often tend to be of systemic origin with secondary cutaneous involvement. Primary cutaneous B-cell lymphomas tend to be indolent disorders, with the exception of primary cutaneous diffuse large B-cell lymphoma-leg type (PCDLBCL-LT). In indolent conditions, the distinction between cutaneous lymphoma and cutaneous lymphoid hyperplasia can be difficult. Integration of all available information, including the clinical setting, is crucial to arriving at the appropriate diagnosis. In this review, we cover the diagnostic approaches to primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, and PCDLBCL-LT, and discuss their differential diagnosis.

Durable Regression of Primary Cutaneous B-Cell Lymphoma Following Fever-inducing Mistletoe Treatment: Two Case Reports

BACKGROUND

Mistletoe is a complementary cancer treatment that is widely used, usually in addition to and alongside recommended conventional cancer therapy. However, little is known about its use, effectiveness, and safety in the treatment of cutaneous lymphoma.

CASE REPORT

Two patients with primary cutaneous B-cell lymphoma (pT2bcNxM0 follicle center and pT2ac-NxM0 marginal zone) either declined or postponed recommended conventional treatment and received high-dose, fever-inducing mistletoe treatment; a combination of intratumoral, subcutaneous, and intravenous application was given; and one patient also underwent whole-body hyperthermia. The lymphoma regressed over a period of 12 and 8 months, respectively, and after administration of a cumulative dose of 12.98 g and 4.63 g mistletoe extract, respectively. The patients are in remission to date, 3.5 years after commencement of treatment. Neither patient received conventional cancer treatment during the entire observation period.

Characteristics of cutaneous marginal zone lymphomas with marked plasmacytic differentiation and a T cell-rich background

Primary cutaneous marginal zone lymphoma (MZL) is a common B-cell lymphoma of skin and is characterized by an infiltrate of neoplastic marginal zone B cells typically within the marginal zones of reactive lymphoid follicles and the interfollicular region. However, in our experience, many cases have underemphasized features such as marked plasmacytic differentiation and/or a prominent T-cell component, which may obscure the neoplastic B cells and lead to misdiagnosis. We wanted to draw attention to these features and have studied 15 cases of MZL with marked plasmacytic differentiation, 10 of which had numerous T cells, some with cytologic atypia, and few B cells in the interfollicular region. Plasma cells were monotypic in all cases by in situ hybridization. By polymerase chain reaction, 6 of 8 T cell-rich cases had an IGH gene rearrangement, and none were clonal for T-cell receptor gene. We discuss the terminology, morphologic features, molecular profile, behavior, and differential diagnosis of cutaneous MZL.

Extranodal lymphomas of the head and neck

Malignant lymphomas represent approximately 5% of all malignant neoplasms of the head and neck and may involve nodal or extranodal sites. Nodal head and neck lymphomas are similar to other nodal sites and are not further reviewed here. The head and neck region is the second most frequent anatomical site of extranodal lymphomas (after the gastrointestinal tract). Most are non-Hodgkin's lymphomas of B-cell lineage, and overall diffuse large B-cell lymphoma is the most common type. Hodgkin's lymphoma rarely occurs in extranodal sites. Other hematologic neoplasms that commonly involve extranodal sites of the head and neck are also discussed. In this review, we begin by discussing lymphomas involving the head and neck according to anatomical site. Then we discuss specifically the pathological findings of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, plasmablastic lymphoma, extramedullary plasmacytoma, and extranodal natural killer/T-cell lymphoma of nasal type.