Although primary cutaneous immunocytoma/marginal zone B-cell lymphoma (PCI/MZBL) is considered as an indolent lymphoma with excellent prognosis, extracutaneous spread and even death due to disseminated disease have been reported. This is a case report of a PCI/MZBL showing dissemination to the regional lymph node and bone marrow, 22 months after the initial diagnosis. Furthermore, in the lymph node, there were focal areas of high-grade transformation. On the other hand, the bone marrow involvement displayed low-grade morphology. We suggest that it should be kept in mind that there is still a possibility of systemic involvement in PCI/MZBL.