Background: CD34 is a transmembrane phosphoglycoprotein that plays a role in modulating cell adhesion and myofibro-blastic differentiation. A superficial CD34-positive fibroblastic tumor was first identified as a clinical and pathological entity in 2014; it is a rare mesenchymal neoplasm of borderline malignancy that can occur in the superficial adipose tissue anywhere on the body.
Case Report: This is a case of a female patient aged 38 years who was referred to a surgeon due to tumefaction in the left paraxial region. The tumor was excised in toto and pathohistological analysis confirmed a superficial CD34-positive fibroblas-tic tumor. Immunohistochemical staining was positive for CD34 and additional analysis for signal transducer and activator of transcription and mouse double minute 2 proteins revealed negative staining. It was decided that no additional therapy was needed; however, regular follow-ups were recommended.
Conclusion: This case posed an additional diagnostic and therapeutic challenge due to the localization of the tumor in the breast of a female patient. Special care was needed to exclude a possible breast neoplasm as well as dermal or soft tissue neoplasm. Diagnosis of a superficial CD34-positive fibroblastic tumor should be considered in all CD34-positive tumors with bizarre, irregular nuclei and no proliferative activity.