Fibro‐osseous tumour of the second metacarpal bone in a Thoroughbred filly

Abstract

SummaryA 7-month-old Thoroughbred filly was evaluated because of an enlarging mass present on the proximomedial aspect of the left metacarpus. The mass was first noticed at age 2 months and had continued to increase in size. The mass was firm, nonpainful to palpation, covered with normal haired skin and had never been associated with lameness. Radiographs obtained at ages 2 and 7 months revealed an enlarging and partially mineralised mass associated with the second metacarpal bone. Based on the clinical and radiographic progression, as well as the location of the mass, a poor prognosis for future athletic soundness was given and the filly was subjected to euthanasia. The mass had histological features of both an ossifying fibroma and osteoma.

Bone tumour classification: Still a work in progress

“…In spite of all that they do not do, case reports remain essential to the development of medical knowledge, and the case report by Madron et al . () illustrates why.…”

“…Madron et al . () have taken a more general approach in their report, diagnosing a fibro‐osseous tumour of bone because of mixed morphology. Thompson and Pool () reiterate a hypothesis that ossifying fibroma may mature toward osteoma, and this could explain the mixed appearance of the tumour in the filly described.…”

“…They often do not provide new insights into the nature of a disease by delving into its pathogenesis, they tend not to identify new cell markers or genetic determinants, and they may not even reveal previously unrecognised morphological characteristics. In spite of all that they do not do, case reports remain essential to the development of medical knowledge, and the case report by Madron et al (2013) illustrates why.…”

“…Unfortunately, there are only so many terms that will accurately describe bone tumour morphology. Table 1, an attempt to pull together the most commonly used diagnostic terms for the relevant tumours of bone in human and veterinary classification schemes, illustrates the classification confusion Madron et al (2013) point out in their report. Clarity in bone tumour diagnostics could be enhanced by associating species with diagnoses.…”

“…As an example, human osteoblastoma would carry with it an understanding of location and prognosis that will probably differ from equine osteoblastoma. Madron et al (2013) have taken a more general approach in their report, diagnosing a fibro-osseous tumour of bone because of mixed morphology. Thompson and Pool (2002) reiterate a hypothesis that ossifying fibroma may mature toward osteoma, and this could explain the mixed appearance of the tumour in the filly described.…”