Systemic hematological malignancies can present in the skin as specific secondary cutaneous lymphoma or as non-specific skin manifestations. In the majority of cases, patients are first diagnosed with a systemic lymphoma and may subsequently develop skin involvement. Rarely, the cutaneous symptoms precede the diagnosis of systemic hematological disorders. In these patients, cutaneous infiltrates can present a challenge to both the clinician and the pathologist. We report a series of five patients with clinically and histologically heterogeneous characteristics, in which careful diagnostic procedures finally led to the diagnosis of systemic hematological malignancies. Interdisciplinary clinical and laboratory examination, including histological and molecular analysis and imaging rendered possible the diagnosis of the underlying hematological malignancy. The here-described approaches allowed the diagnosis and therapy of so-far unrecognized hematological malignancies in patients initially presenting exclusively with cutaneous symptoms.
