IgG4-Related Skin Disease Presenting as a Pseudolymphoma in a White Adolescent Girl.

Immunoglobulin gamma (Ig) type 4-related disease (IgG4-RD) is a chronic immunologic systemic disorder that has gained worldwide recognition in the past decade. This entity can affect almost every organ system, and its characteristic lesions have been found in a variety of organs such as lacrimal and salivary glands, pancreas, liver, bile ducts, lungs, kidneys, retroperitoneum, breast, aorta, thyroid, and prostate. This case reports a very rare case of IgG4-RD presenting with a cutaneous lesion in a young female patient mimicking a lymphoproliferative disorder. IgG4-RD affecting the skin is a rare entity and has mostly been reported in Japanese men of middle to older age. IgG4-RD with cutaneous involvement should be in the differential of non-neoplastic, lymphomas, autoimmune, and infectious disorders of the skin.

Extranodal Marginal Zone Lymphoma-like Presentations of Angioimmunoblastic T-Cell Lymphoma: A T-Cell Lymphoma Masquerading as a B-Cell Lymphoproliferative Disorder.

Angioimmunoblastic T-cell lymphoma (AITL) is the second most common type of peripheral T-cell lymphoma worldwide, and in some countries, it is the most common form. Clinically, AITL usually presents with systemic symptoms, diffuse lymphadenopathy, hepatosplenomegaly, and common laboratory abnormalities such as hypergammaglobulinemia. Rashes are seen in 50%-80% of patients. AITL derives from follicular T-helper cells (TFH), that express germinal center markers and produce hyperactivation of B-cells seen in AITL. Although the histological features of AITL in the skin could be similar to pathological findings present in lymph node biopsies, herein, we present 2 cases of AITL with histological and immunophenotypic features that were somewhat suggestive of extranodal marginal zone lymphoma. Caution is urged to exclude the possibility of a systemic T-cell lymphoma such as AITL in cutaneous and lymph node B-cell proliferations.

(18)FDG PET/CT appearance in primary cutaneous diffuse large B-cell lymphoma, leg type.

We report the case of a 70-year-old woman who presented with a small and painless red skin nodule in the right lower leg, which rapidly and significantly increased in size over few weeks and developed a central eschar. Skin biopsy was consistent with primary cutaneous diffuse large B-cell lymphoma, leg type (PCDBCL-LT), an aggressive and rare cutaneous lymphoma. F-FDG PET/CT showed a hypermetabolic soft tissue mass in the right leg with no evidence of systemic involvement of disease.

Pathology of T-cell lymphomas: diagnosis and biomarker discovery.

T-cell lymphomas are a group of predominantly rare hematologic malignancies that tend to recapitulate different stages of T-cell development, in a similar way that B-cell lymphomas do. As opposed to B-cell lymphomas, the understanding of the biology and the classification of T-cell lymphomas are somewhat rudimentary, and numerous entities are still included as 'provisional categories' in the World Health Classification of hematolopoietic malignancies. A relevant and useful classification of these disorders have been difficult to accomplish because of the rarity nature of them, the relative lack of understanding of the molecular pathogenesis, and their morphological and immunophenotypical complexity. Overall, T-cell lymphomas represent only 15 % of all non-Hodgkin lymphomas. This review is focused on addressing the current status of the categories of mature T-cell leukemias and lymphomas (nodal and extranodal) using an approach that incorporates histopathology, immunophenotype, and molecular understanding of the nature of these disorders, using the same philosophy of the most recent revised WHO classification of hematopoietic malignancies.