A 63-year-old woman presented with a palpable tumor in the left parietal area. Her medical history was remarkable only for hypothyroidism. Head computed tomography (CT) revealed an extradural tumor measuring 57 × 75 × 71 mm (Figure 1A). She underwent frontoparietal craniectomy with the resection of the tumor and its intracranial infiltration (Figure 1B). The histopathological examination showed an infiltrate composed of clonal plasma cells; immunophenotyping demonstrated CD138+ cells and κ light chain restriction. Additionally, on Congo red staining, amyloid deposits were also present.

Figure 1. A – computed tomography of the head in the transverse plane (November 2018): within both parietal bones and the squamous part of the frontal bone, with a predominance of the left side, a heterogeneous, expansive focal lesion of approximately 85 × 61 mm in size was detected (arrow), accompanied by bone destruction. The lesion penetrated into the cranial cavity to a depth of about 40 mm, causing the compression of the cerebral lobes and abolition of the subarachnoid space in the frontal areas. B – computed tomography of the head in the transverse plane (January 2019) following craniectomy and CODUBIX plate implantation: a hydrocele in the operative bed and no signs of local recurrence can be seen (arrow).

Urine protein electrophoresis was positive for monoclonal protein. Serum protein electrophoresis showed no abnormalities, but immunofixation electrophoresis showed κ free light chains. The serum free light chain ratio was 99.3. Bone marrow aspirate smear showed 6.5% of plasma cells.

Whole-body, low-dose CT demonstrated diffused osteolytic bone lesions. The patient was diagnosed with multiple myeloma—free light chain disease, international stage 1 and amyloidosis. Colon biopsy was performed, but no amyloid deposits were found.

She was started on the VCD (bortezomib, cyclophosphamide, and dexamethasone) regimen. However, there was no response. The treatment was changed to VDT-PACE (bortezomib, dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, and etoposide), yet without response. She received a single cycle of lenalidomide and dexamethasone and, subsequently, high-dose melphalan and underwent autologous stem cell transplant in September 2019. In February 2020, due to persisting pancytopenia, bone marrow biopsy was performed and showed a 40% plasma cell infiltration and massive amyloid deposits, which most likely were caused by pancytopenia. She was enrolled in the DVd (daratumumamab, bortezomib, and dexamethasone) program in March 2020. After 5 cycles of DVd, she achieved complete remission according to hematological criteria for persistent pancytopenia.

Extramedullary plasmacytomas can be found in approximately 7% to 18% of patients with multiple myeloma at the time of diagnosis and in up to 20% at relapse; the presence of extramedullary plasmacytomas at the time of diagnosis is associated with lower survival.1

Amyloidosis is a systemic disorder with extracellular tissue deposition of misfolded, insoluble fibrils. In light-chain amyloidosis, they are composed of fragments of monoclonal light chains. A variety of signs and symptoms may result from infiltration, including nephrotic range proteinuria, hepatosplenomegaly, heart failure, and peripheral neuropathy.

Amyloidosis may occur alone or in association with other plasma cell dyscrasias and lymphoproliferative disorders. It is an uncommon disease, with approximately 10 cases per million persons per year.2

Similar therapeutic approaches are used in patients with multiple myeloma and amyloidosis. Daratumumab is a humanized high-affinity monoclonal antibody that targets an epitope on CD38—a glycoprotein highly expressed in hematological malignancies including multiple myeloma.3 Its activity in amyloid light-chain amyloidosis was demonstrated in several studies (alone or in a combination), including a recent report from a phase 3 trial (ANDROMEDA [ClinicalTrials.gov identifier, NCT03201965]; daratumumab-VCD) showing a 92% response including 53% cases of complete hematologic response.4 Overall, daratumumab is effective and well tolerated, as demonstrated in our patient.

Unfortunately, in many Central and Eastern Europe countries, more effective treatment combinations are only reimbursed, once certain standard treatments have failed, and access to novel agents is limited.5