CD56+ hematological neoplasms presenting in the skin: a retrospective analysis of 23 new cases and 130 cases from the literature

Background: The aim of this study was to define prognostic parameters and guidelines for diagnosis and treatment for CD56+ hematological neoplasms with first presentation in the skin. Patients and methods: The study group included 153 cases (23 new and 130 from the literature). According to the World Health Organization classification, the group included 15 nasal and 38 nasal-type natural killer (NK)/T-cell lymphomas, 63 blastic NK-cell lymphomas, 14 cutaneous CD30+ lymphoproliferations, 10 cases of myeloid leukemia, six cases of subcutaneous panniculitis-like T-cell lymphoma (SCPLTCL) and seven peripheral T-cell lymphomas, unspecified. Results: In general, these CD56+ hematological neoplasms had a poor prognosis, with only 27% of patients alive after a median follow-up of 12 months. The median survival was 13 months. Nasal and nasal-type NK/T-cell lymphomas and CD56+ SCPLTCL had the worst prognosis, with a median survival of 5, 6 and 5 months, respectively. Only nasal-type NK/T-cell lymphomas presenting with only skin lesions had a somewhat better prognosis (median survival 27 months). In blastic NK-cell lymphomas (median survival 14 months), age less than or equal to40 years, aggressive treatment with acute leukemia protocols and high TdT expression were associated with a more favorable prognosis. Striking similarities in histology, immunophenotype, clinical presentation and clinical behavior were found between blastic NK-cell lymphomas and CD56+ myeloid leukemias. Conclusions: CD56+ hematological neoplasms presenting in the skin have a poor prognosis, except for primary cutaneous CD30+ lymphoproliferations. The striking similarities between blastic NK-cell lymphomas and CD56+ myeloid leukemias presenting in the skin provide a rationale to treat these patients with more aggressive regimens, rather than with CHOP(-like) regimens and radiotherapy, which have proven to be inadequate therapies for this neoplasm.