Case Presentation: A 43-year-old male with diabetes mellitus type 2 and hypertension, weighing 595 pounds, presented with right leg weakness and 10 falls over the past three months. He recently sustained a left fibular fracture. He sought care at various emergency rooms, however felt dismissed as providers attributed symptoms to his weight and prior injury. He developed progressive neurological symptoms, including bilateral lower extremity paresthesia, constipation, urinary incontinence, and impaired gait which raised concerns of cord compression. Physical exam showed 1/5 strength in right hip flexion and knee extension, 2/5 strength in left hip flexion, and 4/5 strength in left knee extension. Bilateral positive Babinski reflex with decreased sensation below the L5 dermatomes. X-ray confirmed a right fibular spiral fracture. A CT revealed an expansive T8 vertebra lytic lesion, extending to T7, causing severe thoracic spinal narrowing. Serum protein electrophoresis identified MGUS. MRI not performed due to equipment size limitations. CT myelogram and percutaneous biopsy were attempted; however, the necessary equipment could not fit in the scanner with the patient. He underwent an open biopsy with multi-level thoracic fusion and decompression requiring ICU monitoring post-op. Pathology revealed a plasma cell myeloma. A negative bone marrow aspirate confirmed solitary plasmacytoma. Radiation oncology deferred therapy until the patient weighed less than 500 pounds due to technology weight restrictions. He was started on semaglutide. Discharge weight was 502 pounds.
Discussion: This case presents a rare malignancy in a young, morbidly obese male with atypical features, emphasizing the need of high suspicion for solitary bone plasmacytoma, especially with progressive neurologic symptoms and recurrent falls. Solitary bone plasmacytoma (SBP), a rare form of plasma cell dyscrasia of the axial skeleton, presenting as painful osteolytic lesions or pathologic fractures in individuals 55-60 years old with 50% progressing to multiple myeloma (MM). (1-3) Diagnosis relies on MRI/PET-CT imaging and biopsy. Although the risk factors for plasmacytoma are not yet defined, risk factors for other plasma cell dyscrasias, like MM and monoclonal gammopathy of undetermined significance (MGUS) can be considered. Obesity is a risk factor for MM and increases risk of MGUS progression to MM.(4-5) Notably, obesity prevalence rose from 30.5% in 2000 to 41.9% in 2020, while severe obesity (body mass index of 40 kg/m² or higher) doubled. (6-7) Diagnostic imaging is vital, though weight and size limits pose significant constraints, often leading to more invasive diagnostic methods with higher complication rates compared to percutaneous core needle biopsy. (8-10) Thus, careful consideration of risks associated with different diagnostic modalities is essential.Weight bias in medicine can result in delayed diagnoses and suboptimal care. Healthcare providers may unconsciously misattribute symptoms in overweight patients to their weight rather than investigating underlying causes. (11-14) Our patient’s falls were initially linked to a fibular fracture and musculoskeletal issues, delaying the diagnosis of cancer.
Conclusions: This case highlights the challenges of diagnosing SBP in a patient with morbid obesity. Technology limitations and weight bias may obscure key symptoms resulting in missed early diagnosis opportunities.