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. (Jue,) realizaron un informe de caso en Sarcoma Pleomórfico Indiferenciado (n=1). Un hombre de 52 años con sarcoma pleomórfico que exhibía una rara diferenciación dual de músculo liso y osteogénica se presentó con lesiones líticas que mimetizaban una discrasia de células plasmáticas.