Benign reactive lesion with atypical mitosis: New example of an old story

Hua Zhong,Malik Deen,Marina Chekmareva,Michael May,Nicola Barnard,Steven Deak

doi:10.5348/ijcri-2014-03-481-cr-12

Abstract

Ischemic fasciitis (atypical decubital fibroplasia) is a benign reactive lesion that may mimic mesenchymal malignancy. Atypical mitosis has never been reported in such a lesion, which adds an additional challenge to differential diagnosis. A 94-year-old chronically immobile and debilitated female presented with a slightly painful and rapidly growing mass over her right back. Based on the clinical and histological features of the lesion, the diagnosis of ischemic fasciitis, a benign reactive lesion of the deep dermis, was made. Active mitosis and atypical mitotic figures were demonstrated in the lesion. Ischemic fasciitis may show atypical mitotic figures that can mislead differential diagnosis.

Highlights

Ischemic fasciitis is a benign reactive lesion that may mimic mesenchymal malignancy
Atypical mitosis has never been reported in such a lesion, which adds an additional challenge to differential diagnosis
Others argued against his discovery and believed that atypical mitosis could only occur in carcinomas, sarcomas or unusual inflammatory reaction in a Cysticercus rat model of which cells with atypical mitosis eventually resulted in malignancy [1]

Summary

Introduction

In 1892, based on cancer research papers published in the early 20th century, Dr Stroebe discovered asymmetrical division, or atypical mitosis, in nonmalignant processes with reactive or regenerative changes. The patient presented with a slightly painful and rapidly growing mass over her right back for two months She denied history of trauma or prior surgical procedure to the region. Cell block showed fragments of granulation tissue or necrotic tissue with small cysts, which was basically similar histology as demonstrated in the resection specimen (Figure 2A–F). Smaller cells with similar cytoplasmic features were shown with lightly smudged nuclei or occasionally with no appreciable chromatin materials (Figure 2C, D). These cells demonstrated strongly diffuse immunoreactivity for vimentin, were weakly for CD68 (cytoplasmic), weakly focal for CD31, but were completely negative for pancytokeratin and S100. Overall findings favored a reactive process— an entity with so-called ischemic fasciitis/atypical decubital fibroplasia that may show active mitosis, whereas atypical mitotic figures have never been reported in such a lesion

DISCUSSION

CONCLUSION