Fine Needle Aspiration Cytology of Pigmented Dermatofibrosarcoma Protuberance (Bednar Tumor) & it’s Pathogenesis

Abstract

Dermatofibrosarcoma protuberance is a soft tissue tumor of low malignant potential. At times it is
associated with pigment deposits which are then it is termed as Bednar tumor. Only a few Fine Needle Aspiration
Cytology studies of Bednar Tumor have been reported. We share our findings of Fine Needle Aspiration
Cytology in a 30 year old man with Bednar tumor of scalp and multiple enlarged cervical lymph nodes. Our
smears revealed scattered atypical large round to oval cells with scant cytoplasm. Some cells’ cytoplasm
contained abundant melanin pigment which also resulted in dirty black pigmented background. The tissue
sections showed melanin in both spindle shaped cells and rounded cells. At places it seemed that heavily
pigmented cells became oval and globular and necrotic. The melanin pigment was extended into the cellular
processes. The overlying skin epidermis shows focal kilocytotic type change. The tissue sections showed
positivity for CD 34 and protein S-100. We propose that round globular cells are derived from spindly cells after
melanin synthesis and when the cytoplasm is overloaded with melanin the cells undergo necrosis. Focal
kilocyototic type change in overlying epidermis deserves further investigation.