Primary mucosal melanoma of the maxillary sinus with spontaneous rupture of liver metastasis.

Spontaneous rupture of primary liver tumors is a well-recognized and potentially life-threatening complication of hepatocellular carcinoma, whereas rupture of metastatic liver tumors is rare. We report the case of a 60-year-old woman with spontaneous rupture of liver metastasis from a mucosal melanoma, a rare subtype of malignant melanoma. Intraperitoneal bleeding was controlled by transcatheter arterial embolization, and liver tumor biopsy confirmed metastatic melanoma. The maxillary sinus was identified as the primary site. Based on the clinical course, the liver metastases appeared over a short period and progressed rapidly. In addition, contrast-enhanced computed tomography (CT) performed immediately before rupture showed overall poor but heterogeneous enhancement of the ruptured tumor, with a tortuous dilated intratumoral vessel penetrating the lesion. Three-dimensional CT angiography reconstructed from this CT dataset demonstrated that the penetrating vessel represented a tumor-feeding artery, which was morphologically more consistent with a pre-existing hepatic vessel altered by tumor progression than with a newly formed tumor neovessel. Although rare, rupture of metastatic liver tumors may be associated with rapid tumor growth. Importantly, a tortuous dilated intratumoral vessel identified on pre-rupture CT may represent an imaging feature associated with tumor fragility and impending rupture.