BACKGROUND: In nodal anaplastic large cell lymphoma, strong expression of galectin-3 (Gal-3) has been found, but only very few cases of primary cutaneous lymphoma have so far been examined.
OBJECTIVES: To investigate 11 primary cutaneous anaplastic large cell lymphomas (PCALCL), 47 lymphomatoid papuloses (LYP) and 14 cases of transformed mycosis fungoides with CD30 expression (MF-T) for Gal-3 expression.
METHODS: A Gal-3 score was applied using a photo-based morphometric evaluation program. Double staining for CD30 and Gal-3 was performed. Furthermore, we recorded the cellular and extracellular sublocalization of the signal.
RESULTS: The Gal-3 expression in CD30+ tumor cells was significantly lower in MF-T in contrast to CD30+ lymphoproliferative disorders (CD30 LPD; p < 0.001), but we found no differences between PCALCL and LYP (p = 0.42). In PCALCL Gal-3 was more often localized in the cytoplasm in contrast to LYP, in which an equal distribution in the cytoplasm and the nucleus was more common (p = 0.9).
CONCLUSIONS: The lower Gal-3 expression in MF-T in comparison to CD30 LPD might be an additional criterion to differentiate both entities. The different sublocalization of the Gal-3 signal might reflect a different biological function and behavior.