Background: Primary cutaneous plasmacytomas, a localized collection of neoplastic plasma cells, may present without bone marrow involvement. Secondary plasmacytomas can complicate the clinical course of multiple myeloma (MM). Both types of cutaneous plasmacytoma are commonly observed in the terminal stages of MM.
Case report: We present the case of a 37-year-old Turkish man diagnosed with lambda light chain MM. The patient had numerous firm plaque-shaped cutaneous lesions on the left side of the chest, the left shoulder, and the right preauricular region without concurrent bone marrow disease. Histopathological examination of the cutaneous plaque on the left side of the chest revealed neoplastic plasma cells infiltrating the dermal region. Furthermore, the cytologic examination of cerebrospinal fluid disclosed lymphoplasmacytic cells. The patient was treated with VDTPACE (bortezomib + dexamethasone + thalidomide + adriamycin + cyclophosphamide + etoposide), and the cutaneous lesions disappeared. Central nervous system involvement was treated with craniospinal irradiation and intrathecal chemotherapy.
Conclusion: Cutaneous involvement of MM is an unusual clinical presentation, but a high level of suspicion is advisable in patients with MM and skin lesions. The involvement of the skin was associated with advanced disease status and, therefore, with a poor prognosis. This is the first reported case of cutaneous involvement of lambda light chain MM.