Eruptive Cutaneous Metastases of Leiomyosarcoma Following a 26-Year Latency

Introduction: Leiomyosarcomas are malignant tumors of smooth muscle origin that infrequently involve the skin. We report a case of eruptive cutaneous leiomyosarcoma metastases occurring over two decades after excision of a primary subcutaneous leiomyosarcoma, representing an unusually long latency period and unique metastatic pattern. Case Presentation: An 85-year-old Black man presented with several months of pruritic, firm cutaneous nodules on the scalp, palm, and shoulder. His history was notable for a subcutaneous high-grade leiomyosarcoma of the right forearm excised with negative margins 26 years earlier and an incidentally discovered hepatic mass five years prior to presentation. Biopsies of the cutaneous nodules revealed atypical spindle cell proliferations positive for smooth muscle actin and desmin, consistent with leiomyosarcoma. PET imaging demonstrated an infiltrative hepatic mass invading the right kidney and numerous pulmonary and adrenal metastases. Histopathologic correlation confirmed metastatic leiomyosarcoma involving the liver and skin. The patient ultimately elected palliative gemcitabine monotherapy. Discussion: Cutaneous metastases from leiomyosarcoma are rare and usually indicate advanced disease. The unusually long latency in this case raises the possibility of either delayed metastatic spread from the original subcutaneous tumor or a new primary hepatic lesion. Recognition of such atypical presentations underscores the importance of maintaining diagnostic suspicion in patients with a remote history of leiomyosarcoma. Conclusion: This case highlights a rare instance of late eruptive cutaneous metastases following prior subcutaneous leiomyosarcoma. Clinicians should maintain long-term vigilance, as late metastases may occur even after prolonged periods without clinical evidence of disease.