Cytologic features of reactive fibroplasia in cutaneous and subcutaneous lesions of dogs: A retrospective study

Abstract

Background: Determining reactive fibroplasia from primary neoplastic proliferation can be difficult using the cytologic features of spindle cells.

Objectives: This study aimed to describe qualitative features of benign reactive spindle cells and provide a diagnostic tool to distinguish between fibroplasia and soft tissue sarcoma.

Methods: Cytologic samples from cutaneous lesions with histopathologically confirmed fibroplasia were reviewed and compared with cytologic samples from confirmed low-grade soft tissue sarcomas. The samples were obtained from the Archive of the Laboratorio Veterinario Bresciano (Brescia; Italy).

Results: A total of 25 cytologic samples retrieved from the database fit the selection criteria. For comparison, 25 cytologic samples of histopathologically confirmed soft tissue sarcomas with secondary inflammation were obtained and reviewed from the same database. A low number of singularly distributed spindle cells with mild features of atypia and a high ratio of inflammatory to spindle cells was observed in confirmed cases of fibroplasia.

Conclusions: Low cellularity, individualized spindle cells, and an increased inflammatory-to-spindle cell ratio were more indicative of fibroplasia than sarcoma.

Keywords: cytology; fibroplasia; inflammation; sarcoma; spindle cells.