Soft tissue sarcoma with ZC3H7B::BCOR fusion in a male mimicking low-grade fibromyxoid sarcoma - A case report.

Diagnosis of soft tissue tumors is often challenging, given the large number of entities, often with non-specific or overlapping morphology. Although morphology still plays an important part in diagnostic process, additional studies including immunohistochemistry and molecular genetics are often needed to arrive at correct diagnosis. We report a case of 61-year-old male with subcutaneous tumor in right hip area, that was surgically removed. The tumor was composed of uniform bland spindle cells in mild to moderately cellular myxoid nodules, with limited areas of collagenization and the diagnosis of low grade fibromyxoid sarcoma was made. The tumor recurred 3 years after the initial diagnosis and the new sample showed a high-grade round cell sarcoma with limited residual low-grade areas and non-specific immunoprofile after extended immunohistochemical work-up. Molecular analysis demonstrated ZC3H7B::BCOR fusion. Sarcomas with ZC3H7B::BCOR fusion occurring outside of uterus are exceedingly rare. A comprehensive review of previously published cases and a short discussion about classification of the entity is provided, together with data about morphology and immunoprofile of the lesions. The case also underscores the necessity of extended work up of soft tissue tumors with unusual immunohistochemical or morphological features in order to accurately assess their biological potential.

Problematic Imaging Diagnostics of Musculoskeletal Gossypiboma with Chronic Expanding Hematoma Mimicking Malignant Lesion.

Both musculoskeletal gossypibomas and chronic expanding hematomas have been rarely reported; the reports that do exist are usually case reports. Our objective is to demonstrate problematic imaging diagnostics of an unusual presentation mimicking a malignant lesion. We report the case of a 47-year-old man who underwent bone graft harvesting from the iliac crest for spinal fusion due to scoliosis at 18 years of age, and 29 years later, he developed a growing, painful tumor at the original donor site (a bone defect in the iliac crest). It was challenging to differentiate a hematoma from a malignant tumor based solely on clinical and radiological workup, including an ultrasound-guided needle biopsy focused on viable tissue. The definitive diagnosis of a gossypiboma with a chronic expanding hematoma was based on histopathological assessment after wide surgical resection-a chronic expanding hematoma with multiple foamy macrophages and giant cells engulfing foreign material (original surgical hemostatic sponge).