A 52-year-old male with pleomorphic sarcoma exhibiting rare dual smooth-muscle and osteogenic differentiation presented with lytic lesions mimicking plasma cell dyscrasia.
Case Report (n=1)
Undifferentiated pleomorphic sarcoma with dual divergent differentiation can mimic hematologic malignancies on imaging, requiring careful histopathological and immunohistochemical correlation.
Introduction: Pleomorphic sarcoma (PS) is a high-grade soft-tissue malignancy with marked morphologic variability. Divergent differentiation is recognized, but dual smooth-muscle and osteogenic lineage differentiation is exceedingly rare and may mimic other malignancies. Case Report: A 52-year-old male presented with progressive low-back pain, weight loss, and an enlarging iliac mass. Magnetic resonance imaging showed multiple lytic lesions suggestive of plasma-cell dyscrasia; however, serum electrophoresis was negative. Histopathology revealed high-grade PS, and immunohistochemistry demonstrated simultaneous positivity for smooth-muscle actin and osteocalcin, confirming dual smooth-muscle and osteosarcomatous differentiation. The patient was referred to oncology for multidisciplinary management. Conclusion: PS with dual divergent differentiation represents a rare diagnostic challenge. Clinical and imaging features may falsely suggest hematologic malignancy, underscoring the necessity of correlating radiology, histopathology, and immunohistochemistry.
Rathod et al. (Thu,) conducted a case report in Undifferentiated Pleomorphic Sarcoma (n=1). A 52-year-old male with pleomorphic sarcoma exhibiting rare dual smooth-muscle and osteogenic differentiation presented with lytic lesions mimicking plasma cell dyscrasia.