81-year-old male with progressive thrombocytopenia, peripheral blood monocytosis and a diagnosis of chronic myelomonocytic leukemia presented to dermatology with innumerable, pruritic, indurated, erythematous papules. The papules had slowly progressed over five years, starting on the face and then generalizing.  Previous skin biopsies had been interpreted as lymphohistiocytic response to ruptured follicle and necrotizing granulomatous dermatitis.  Retrospective review of five skin biopsies over five years showed lymphohistiocytic infiltrates in the dermis culminating with nodules of histiocytes surrounded by lymphocytes and focal necrosis.  The histiocytes in all biopsies were positive for CD1a and negative for Langerin, S100, CD30, ALK and VE1. The peripheral blood had 23,800 white cells / mL, 57% monocytes, 1.5% blasts and 60,000 platelets.  Next generation sequencing for common aberrations in myeloid neoplasms identified a TET2 and canonical SRSF2 mutations.  The bone marrow was hypercellular with 87% blasts. The patient was diagnosed with cutaneous indeterminate cell histiocytosis associated with CMML and transformation to acute myeloid leukemia (AML).  Cutaneous Langerhans cell lesions, juvenile xanthogranuloma and xanthoma disseminatum are known to sometimes occur in patients with myeloproliferative disorders and leukemia cutis. Additionally, CD1a+, Langerin -, S100- phenotype has been reported.  The skin pathology findings in our patient, however, showed a spectrum of mixed lymphohistiocytic pattern evolving to nodules with central necrosis surrounded by lymphocytes and the histiocytes did not resemble blasts.  Progressive skin lesions containing histiocytes in a patient with an underlying myeloproliferative disorder should be a clue to the possibility of skin involvement by a paraneoplastic histiocytic process or leukemia cutis.