Background
We studied the clinicopathologic features of superficial CD34-positive fibroblastic tumor (SCPFT), which is a newly described neoplasm, to enhance the recognition and diagnostic level of the disease. Case presentation: We herein report two cases of superficial CD34-positive fibroblastic tumors in a 33-year-old man and a 30-year-old man. The 33-year-old man presented with a slow-growing subcutaneous nodule 5.0 cm in diameter on the right thigh, and the 30-year-old man developed a painful lump 4.0 cm in diameter on his right thigh. Histologically, the tumor was located in superficial soft tissue with relative circumscription. Tumors had abundant spindled polygonal cells, which were arranged in fascicular or sheet-like patterns. Neoplastic cells were characterized by polymorphic nuclei, granular cytoplasm, intranuclear cytoplasmic pseudoinclusions, and an extremely low mitotic rate. Immunohistochemically, neoplastic cells showed diffuse and strong CD34 expression and focal cytokeratin staining. The expression of S-100 protein, SMA, CD99, H-caldesmon, ALK-1, and bcl-2 were all negative. The Ki-67 index was low. Conclusions: SCPFT is a rare low-grade fibroblastic tumor that has typical morphologic features and unique biologic behavior. Familiarity with clinicopathologic characteristics of the tumor contributes to the differential diagnosis of similar tumors.
Conclusions
SCPFT is a rare low-grade fibroblastic tumor that has typical morphologic features and unique biologic behavior. Familiarity with clinicopathologic characteristics of the tumor contributes to the differential diagnosis of similar tumors.