Untreated plasmacytoma of bone containing macroscopic intralesional fat and mimicking intraosseous lipoma: A case report and review of the literature

• Published in: Clinical imaging 2020-08, Vol.64, p.18-23
• Main Authors: Hansford, Barry G., Hanrahan, Christopher J., Girard, Nicole, Silbermann, Rebecca, Morag, Yoav
• Format: Article
• Language: English
• Subjects: Biomedical materials; Biopsy; Bone; Bone imaging; Bone lesions; Bone marrow; Cancer therapies; Case reports; Computed tomography; Fat; Fractures; Hematopoiesis; Intraosseous lipoma; Lesions; Lipoma; Literature reviews; Magnetic resonance imaging; Medical imaging; Metastases; Metastasis; Mimicry; MRI; Multiple myeloma; Neoplasia; Osteolysis; Pain; Papillary thyroid cancer; Patients; Plasma; Plasma cells; Plasmacytoma; Proteins; Radiation; Radiation therapy; Radiographs; Radiography; Shoulder; Soft tissues; Thyroid; Thyroid cancer; Tumors; Urine; Vertebrae
• ISSN: 0899-7071; 1873-4499
• DOI: 10.1016/j.clinimag.2020.03.003

Solitary plasmacytoma is a rare form of plasma cell neoplasm defined by local neoplastic accumulation of monoclonal plasma cells in the absence of systemic proliferative plasma cell disease. In this case report, a 65-year-old female with remote past medical history of papillary thyroid cancer presented with shoulder pain and radiographs showing an aggressive osteolytic lesion presumed to represent an osseous metastasis. The subsequent MRI and CT examinations demonstrated diffuse intralesional macroscopic fat without a nonlipogenic soft tissue component or focal, nodular mass-like enhancement. The presence of macroscopic fat in an untreated osseous lesion suggested a benign lesion with the favored diagnosis an intraosseous lipoma with non-displaced pathological fracture. Therefore, the decision was made to forego image-guided percutaneous biopsy and instead proceed directly to open surgical biopsy and partial distal claviculectomy. Pathology of the resected specimen showed focally dense infiltration of plasma cells within the marrow space and scant hematopoiesis compatible with a plasma cell neoplasm. To the best of our knowledge, this is first case report of solitary plasmacytoma of bone, or any untreated plasma cell neoplasm, containing macroscopic fat upon imaging. The decision to forego image-guided percutaneous biopsy had significant treatment implications as the primary therapy for patients with SPB is not surgical, but localized radiation therapy. Based on this case, solitary plasmacytoma of bone may be included as one of the rare fat containing malignant bone lesions and imaging guided percutaneous biopsy should be considered in symptomatic fat-containing bone lesions. •Non-treated microscopic or macroscopic fat-containing bone lesions are overwhelmingly benign•We report the first case of a non-treated solitary plasmacytoma with macroscopic intralesional fat•Image-guided percutaneous biopsy should be considered for symptomatic fat-containing bone