Glomangiosarcoma of the hip: report of a highly aggressive tumour with widespread distant metastases

Malignant glomus tumour is an extremely rare neoplasm, and only a few cases with local invasive or aggressive features have been described to date. We present a distinctive case of a malignant glomus tumor arising on the skin of the left hip of a 47-year-old woman. The primary tumour was small, with a maximum diameter of 1 cm, but 2 years after the tumour was excised, multiple lung and skin metastases appeared. Post-mortem examination also revealed widespread metastases in almost all of the visceral organs. Histological examination showed that the primary tumour was composed of a sheet-like proliferation of epithelioid round or short spindle cells surrounding small venules. In addition, there was a proliferation of long spindle cells with eosinophilic fibrillary cytoplasm, which mimicked a leiomyosarcoma. The tumour cells were intensely immunopositive for actin and vimentin but were negative for desmin. This is an exceptional case of malignant glomangiomyoma with widespread metastases, which represents a distinct variant of de novo glomangiosarcoma.