Background TOX (thymocyte selection-associated high-mobility group box) was shown to be aberrantly expressed in mycosis fungoides (MF) and Sézary syndrome (SS) and is suggested to have additional... Show moreBackground TOX (thymocyte selection-associated high-mobility group box) was shown to be aberrantly expressed in mycosis fungoides (MF) and Sézary syndrome (SS) and is suggested to have additional diagnostic value. However, data on expression in other types of cutaneous T-cell lymphoma (CTCL) are scarce and it is unknown whether TOX is only expressed by MF with a CD4+CD8- phenotype. Objectives To investigate TOX expression in various types of CTCL with different T-cell phenotypes. Methods Immunohistochemical expression of TOX was evaluated on 153 skin biopsies of 132 patients with CTCL and 60 patients with benign inflammatory dermatoses (BID). Results TOX was expressed by more than 50% of the neoplastic T-cells in 49 of 59 patients (83%) with MF, and in 19 of 22 patients (86%) with SS. The TOX+ cases of MF included 34 of 35 cases (97%) with a CD4+CD8- phenotype, but also five of eight cases (63%) with a CD4-CD8+ phenotype and 10 of 16 cases (63%) with a CD4-CD8- phenotype. TOX expression in other types of CTCL was common but showed variable intensity. Although only 1 of 60 patients (2%) with a BID expressed TOX in > 50% of the skin-infiltrating T cells, some caution is warranted, as the majority of BIDs had TOX+ T cells varying between 11% and 50%.Conclusions TOX expression is not tumour specific, is not restricted to CTCL with a CD4+CD8- phenotype, and, on its own, is insufficient for diagnosis of CTCL. However, it may have an adjunctive diagnostic role in conjunction with other clinical and histological data. Show less
Background Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is rare. Guidelines for staging, treatment and follow-up are lacking. Objectives To better define staging... Show moreBackground Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is rare. Guidelines for staging, treatment and follow-up are lacking. Objectives To better define staging procedures, treatment results and clinical course in adult patients with LCH first presenting in the skin. Methods Eighteen adult patients with LCH first presenting in the skin were collected from five centres collaborating in the Dutch Cutaneous Lymphoma Group. Clinical records and (skin) biopsy specimens were reviewed and follow-up data were obtained. A literature search on adult patients with LCH presenting in the skin was performed. Results Staging procedures showed extracutaneous disease in three of 16 patients who were adequately staged. One patient had a histologically confirmed lytic LCH bone lesion, while two patients had a myelodysplastic syndrome. During follow-up two of 18 patients developed extracutaneous localizations of LCH. Five patients developed a second haematological malignancy, including (myelo)monocytic leukaemia (two cases), histiocytic sarcoma (one case), diffuse large B-cell lymphoma (one case) and peripheral T-cell lymphoma (one case). Review of the literature revealed six other adult patients with a second haematological malignancy preceding or following a diagnosis of LCH. Conclusions The results of the present study suggest an increased risk of a second haematological malignancy in adult patients with LCH presenting in the skin. Extensive staging at presentation and long-term follow-up are therefore warranted in such patients. Show less
