title: Folliculotropic T-cell infiltrates associated with B-cell chronic lymphocytic leukaemia or MALT lymphoma may reveal either true mycosis fungoides or pseudolymphomatous reaction: seven cases and review of the literature.
abstract: BACKGROUND
  Mycosis fungoides (MF) and pseudo-MF (or MF simulant) can be associated with B-cell malignancies, but distinction between a true neoplasm and a reactive process may be difficult.
  
  
  OBJECTIVE
  To report seven patients with B-cell malignancy and folliculotropic MF or pseudo-MF and emphasize on criteria allowing distinction between the two conditions.
  
  
  METHODS
  We retrospectively and prospectively included seven patients with B-cell malignancy who presented skin lesions histologically consisting in a folliculotropic T-cell infiltrate and reviewed the literature on the topic.
  
  
  RESULTS
  Four men and three women had a chronic lymphocytic leukaemia (n = 6) or a MALT-type lymphoma (n = 1). Five patients had localized papules, and two had patches and plaques. Histological examination showed in all cases a diffuse dermal T-cell infiltrate with folliculotropic involvement and follicular mucinosis associated with clusters of the B-cell lymphoma, without significant expression of follicular helper T-cell markers. T-cell rearrangement studies showed a polyclonal pattern in the patients with papules and a monoclonal pattern in the cases of patches and plaques. Papular lesions had an indolent evolution, whereas patches and plaques persisted or worsened into transformed MF.
  
  
  CONCLUSIONS
  Folliculotropic T-cell infiltrates associated with B-cell malignancies can be either a true folliculotropic MF or a pseudo-MF. The distinction between both conditions cannot rely only on the histopathological aspect, but needs both a clinical pathological correlation and the search for a dominant T-cell clone. Whether the neoplastic T and B cells derive from a common ancestor or the T-cell proliferation is promoted by the underlying B-cell lymphoma remains unsolved, but interaction between B and T cell in the skin does not appear to be dependent on a TFH differentiation of the T-cell infiltrate.
authors.affiliation: Department of Dermatology, AP-HP, Henri Mondor Hospital, Créteil.
authors.forename: S
authors.initials: S
authors.lastname: Ingen-Housz-Oro
authors.forename: N
authors.initials: N
authors.lastname: Franck
authors.forename: N
authors.initials: N
authors.lastname: Beneton
authors.forename: A
authors.initials: A
authors.lastname: Fauconneau
authors.forename: G
authors.initials: G
authors.lastname: Do-Pham
authors.forename: A
authors.initials: A
authors.lastname: Carlotti
authors.forename: T
authors.initials: T
authors.lastname: Petit
authors.forename: I
authors.initials: I
authors.lastname: Liolios
authors.forename: C
authors.initials: C
authors.lastname: Bara
authors.forename: H
authors.initials: H
authors.lastname: Carpentier
authors.forename: D
authors.initials: D
authors.lastname: Storelli
authors.forename: B
authors.initials: B
authors.lastname: Prophette
authors.forename: L
authors.initials: L
authors.lastname: Garderet
authors.forename: C
authors.initials: C
authors.lastname: Haioun
authors.forename: E
authors.initials: E
authors.lastname: Petit
authors.forename: M-H
authors.initials: MH
authors.lastname: Delfau-Larue
authors.forename: B
authors.initials: B
authors.lastname: Vergier
authors.forename: O
authors.initials: O
authors.lastname: Chosidow
authors.forename: M
authors.initials: M
authors.lastname: Beylot-Barry
authors.forename: N
authors.initials: N
authors.lastname: Ortonne
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D018859:Hair Follicle; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications / Q000276:immunology / Q000473:pathology*; D018442:Lymphoma, B-Cell, Marginal Zone / Q000150:complications / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000150:complications / Q000473:pathology*; D011446:Prospective Studies; D019310:Pseudolymphoma / Q000150:complications / Q000473:pathology*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000150:complications / Q000473:pathology*; D013601:T-Lymphocytes