Case report: A case of solitary plasmacytoma of the skull (SPS) is presented. This report illustrates a rare case of entirely asymptomatic SPS. SPS is an uncommon type of solitary plasmacytoma of the bone (SPB), which is itself a rare disease, accounting for less than 5% of all monoclonal gammopathies (MG). Monoclonal gammopathies are a relatively heterogeneous group of hematological disorders, characterized by the uncontrolled proliferation of a clone of B-lymphocytes. Multiple myeloma, myeloma variants (including SPS), Waldeström’s macroglobulinemia, primary amyloidosis and monoclonal gammopathy of uncertain significance (MGUS) sit within the spectrum of these disorders. The clinical presentation of different types of MG overall depends on the pattern and degree of proliferation of the B-lymphocyte clone, its tendency to secrete cell products such as immunoglobulin or related molecular subunits and the response of the host. Only a small number of cases of SPS have been reported in the English literature. SPS can present with a variety of neurological signs and symptoms that depend on its size and location. However, some cases, such as the one presented here, are entirely asymptomatic. In this case, the tumor was successfully identified and resected.

Discussion: SPS represents a diagnostic challenge by virtue of its highly variable, and often asymptomatic, presentation, and therefore poses the affected patients at increased risk of both intracranial and systemic morbidity, with potentially life-threatening consequences.

Key words: Extra medullary plasmacytoma. Myeloma. Skull tumor. Bone tumor. Solitary plasmacytoma.