Discussion:

Uterine leiomyosarcoma is the most frequent malignant gynecologic mesenchymal tumor. However, it has a low annual incidence of approximately 0.8 per 100 000 women and represents only 1% to 2% of all uterine malignancies. It usually presents during the perimenopausal years with vague symptoms that can mimic other benign entities (anormal uterine bleeding, enlarged uterus, palpable pelvic mass and pelvic pressure or pain). This malignant condition is associated with a poor prognosis. The 5-year survival rate is between 25% and 76%, while the recurrence rate varies from 45% to 75% with the lungs being the most common site of first recurrence (1, 2, 3).

The uterine leiomyosarcomas tend to metastasize hematogenously and the most frequent locations include the lungs (67.7%), cranial/intracranial (16.2%), skin & soft tissues (15.3%), and bones (13.8%). Metastatic disease to the adrenal gland is considered extremely rare. Other unusual sites of metastasis are the liver, pancreas, thyroid, salivary glands, heart, bowels, and breast (4, 5). The median time to first metastasis are considered highly variable (median: 24 months; range, 1 month to 26 years), while the survival rate for patients with metastatic disease at time of diagnosis is approximately 10% to 15%. In terms of treatment, only the resection of the metastases significantly influenced postmetastasis survival in multivariable analysis (1, 4).

Usually, distant metastases of uterine leiomyosarcomas are histologically identical to primary tumors (4). The histopathological features include: spindle cells with blunt-ended nuclei, brisk mitotic activity (>10 mitoses per 10 HPF) with atypical forms, nuclear pleomorphism, hypercellularity with fascicular growth pattern, coagulative necrosis, and infiltration of the myometrium (1). The immunohistochemistry usually shows positivity for smooth muscle actin, desmin, h-caldesmon, histone deacetylase 8 and overexpression of p53 and p16 (1).