Fine needle aspiration cytology of a superficial CD34-positive fibroblastic tumour, including differential diagnoses and recent updates.

BACKGROUND: Superficial CD34-positive fibroblastic tumor is recognized as a distinct tumor of fibroblastic lineage in the recent World Health Organization (WHO) classification of tumors of soft tissues. There is an occasional report on cytomorphologic features of this rare tumor. CASE REPORT: A 28-year-old male presented with swelling in his left thigh of 3 years duration, that was diagnosed as a pleomorphic sarcoma, elsewhere. Radiological imaging showed a well-defined lesion measuring 2.8 cm along the anteromedial aspect of the left mid-thigh in the subcutaneous location. Review of FNAC smears revealed a hypercellular tumor composed of spindle and pleomorphic cells with fine to more vesicular chromatin, and moderate to abundant granular to characteristic "glassy" cytoplasm including cells showing intranuclear pseudo inclusions, devoid of mitotic figures. Interspersed was pink stroma and several inflammatory cells including lymphocytes. Immunohistochemically, tumor cells were diffusely positive for CD34 and focally for AE1/AE3. A diagnosis of superficial CD34-positive fibroblastic tumor was finally offered. CONCLUSIONS: This constitutes one of the first reports of cytomorphologic features of Superficial CD34-positive fibroblastic tumor. Its differential diagnoses, molecular updates and treatment-associated implications are discussed herewith.