DIAGNOSTIC CHALLENGE OF BENIGN FIBROUS HISTIOCYTOMA—A CASE REPORT

In many cases, the microscopic analysis of soft tissue tumors is complex. The final accurate diagnosis usually involves morphology and immunohistochemical characteristics that should be coupled with clinical findings. A 77-year-old female patient presented with an asymptomatic purplish sessile nodule in the hard palate. Serologic examination results showed normal limits. Tomographic image disclosed a well-circumscribed exophytic mass associated with discrete bone reabsorption of floor of the nasal fossa. Histopathologic examination revealed histiocytoid and spindle cell proliferation with multiple pericytomalike vessels in a fibrous connective tissue. An immunohistochemical panel showed a positive stain for CD10, vimentin, CD163, CD68; a negative result for creatine kinase, M type (CKM), CD31, CD 34, p63, S100, smooth muscle actin (SMA), human herpesvirus 8 (HHV-8), desmin, and proliferative index (Ki-67) of 10%. A final diagnosis of benign fibrous histiocytoma was concluded. The healing process was uneventful and no recurrence was observed during 14 months of follow-up.