The lymphohistiocytoid variant of diffuse malignant mesothelioma is rare with very few cases described in the literature. It is characterized by mesothelial cells with a histiocytelike appearance and an associated dense lymphoid infiltrate. We studied clinicopathologic features and immunohistochemical patterns of a series of 22 cases. The histiocytelike cells had a mesothelial immunophenotype: AE1/AE3 (100%), calretinin (100%), CK5/6 (46%), and EMA (52%). The prominent lymphoid component showed a cytotoxic T-cell immunophenotype. Prognosis was similar to that of a large series of epithelioid diffuse malignant mesotheliomas. Formely, it was classified within the sarcomatoid type. We suggest that it should be reclassified as an epithelioid variant because of its similar behavioural characteristics. There was no evidence of Epstein-Barr virus-related infection.
*Mesopath Group, ERI 3 Inserm, CHU Caen
†InVs, Hopital Saint Maurice, Vincennes
‡ERI 3 Inserm, CHU Caen, France
§Department of Histopathology, Llandough Hospital, Cardiff
¶Department of Pathology, University of Aberdeen, UK
∥Histopathology Department, Cork University Hospital, Wilton Cork, Ireland
Supported by the “Institut de Veille Sanitaire” Hopital Saint Maurice, Vincennes, and by grants from the Conseil Régional de Basse Normandie, France.
On the Behalf of the Mesopath Group: A. deQuillacq, I. Abdalsamad, E. Brambilla, F. Capron, MC. Copin, AY. deLajartre, A. Foulet-Rogé, L. Garbe, O. Groussard, L. Guillou, JM. Piquenot, F. Thivolet.
Reprints: Prof Francoise Galateau-Sallé, MD, CHU Caen Cote de Nacre, Avenue Cote de Nacre, Caen, Calvados, France, 14033 Caen Cedex (e-mail: firstname.lastname@example.org).