M Wobser1, S Roth2, T Reinartz1, A Rosenwald2, M Goebeler1, E Geissinger2. 1. Department of Dermatology, Comprehensive Cancer Center Mainfranken, University Hospital Wuerzburg, Josef-Schneider-Str. 2, Wuerzburg, 97080, Germany. 2. Institute of Pathology, Comprehensive Cancer Center Mainfranken, University of Wuerzburg, Wuerzburg, Germany.
Abstract
BACKGROUND: Indolent cutaneous CD8+ lymphoid proliferation is a recently described rare entity among cutaneous T-cell lymphomas that typically presents with solitary skin lesions at acral sites. Separation from otherwise aggressive T-cell lymphomas bearing a cytotoxic CD8+ phenotype is fundamental to avoid unnecessary harmful treatment. However, up to now, no reliable discriminative marker has been identified. OBJECTIVES: Motivated by these diagnostic quandaries, we have analyzed a large series of archived formalin-fixed paraffin-embedded (FFPE) specimens of atypical CD8+ cutaneous infiltrates with clear-cut diagnosis and clinical follow-up (n = 44) including five cases of indolent CD8+ lymphoid proliferation by using immunohistochemistry with the aim of obtaining markers predictive of subtype assignment. RESULTS: We identified exclusive expression of CD68 by lymphoma cells within the subgroup of indolent CD8+ lymphoid proliferation (5/5 cases). Specific CD68 expression in this entity was confirmed by the application of several monoclonal antibodies (KP1, PG-M1, KiM1P) against the CD68 molecule available for FFPE tissue. In contrast, none of the infiltrates of the other CD8+ cutaneous lymphoma entities stained positive for CD68 (0/39). CONCLUSIONS: Based on these observations, we suggest CD68 as a new discriminative marker which is helpful in distinguishing indolent CD8+ lymphoid proliferation from other CD8+ cutaneous lymphomas in ambiguous cases.
BACKGROUND: Indolent cutaneous CD8+ lymphoid proliferation is a recently described rare entity among cutaneous T-cell lymphomas that typically presents with solitary skin lesions at acral sites. Separation from otherwise aggressive T-cell lymphomas bearing a cytotoxic CD8+ phenotype is fundamental to avoid unnecessary harmful treatment. However, up to now, no reliable discriminative marker has been identified. OBJECTIVES: Motivated by these diagnostic quandaries, we have analyzed a large series of archived formalin-fixed paraffin-embedded (FFPE) specimens of atypical CD8+ cutaneous infiltrates with clear-cut diagnosis and clinical follow-up (n = 44) including five cases of indolent CD8+ lymphoid proliferation by using immunohistochemistry with the aim of obtaining markers predictive of subtype assignment. RESULTS: We identified exclusive expression of CD68 by lymphoma cells within the subgroup of indolent CD8+ lymphoid proliferation (5/5 cases). Specific CD68 expression in this entity was confirmed by the application of several monoclonal antibodies (KP1, PG-M1, KiM1P) against the CD68 molecule available for FFPE tissue. In contrast, none of the infiltrates of the other CD8+ cutaneous lymphoma entities stained positive for CD68 (0/39). CONCLUSIONS: Based on these observations, we suggest CD68 as a new discriminative marker which is helpful in distinguishing indolent CD8+ lymphoid proliferation from other CD8+ cutaneous lymphomas in ambiguous cases.
Authors: Rein Willemze; Lorenzo Cerroni; Werner Kempf; Emilio Berti; Fabio Facchetti; Steven H Swerdlow; Elaine S Jaffe Journal: Blood Date: 2019-01-11 Impact factor: 22.113