Gajewski Donald A, Burnette Jeffery B, Murphey Mark D, Temple H Thomas
Department of Orthopaedic Surgery and Rehabilitation, Walter Reed Army Medical Cente, Washington, D.C. 20307, USA.
Foot Ankle Int. 2006 Apr;27(4):240-4. doi: 10.1177/107110070602700403.
Enchondroma is the most common benign tumor of the bones of the foot. Chondrosarcoma in this area is relatively rare with malignant transformation from enchondroma occurring rarely. In contrast to similar tumors in the appendicular skeleton, it is difficult to distinguish between these two tumors when they occur in the foot.
We reviewed the medical records and radiographs of all patients with enchondroma and chondrosarcoma arising from enchondroma (secondary chondrosarcoma) from the radiologic archives at the Armed Forces Institute of Pathology (AFIP) and identified those patients with tumors involving the bones of the foot. There were 755 patients with enchondroma of which 34 (4.8%) involved the foot; there were 340 patients with secondary chondrosarcoma and 14 (4.1%) involved the foot. We compared clinical and radiographic features of both these lesions. We also compared interobserver differences not only for diagnosis but also for the presence of scalloping, fracture, cortical destruction, and mineralized matrix.
Size and location were statistically significant variables differentiating the two tumors (p = 0.03). Enchondromas had a mean size of 2.7 cm(2). Lesions that occurred in the hindfoot and midfoot were more likely to be malignant compared to those in the forefoot. In comparing interobserver reliability, most disagreement occurred regarding the presence or absence of matrix with the examiners concurring only 51% of the time. With regard to diagnosis, the examiners' accuracy was 71% and 80%. Their accuracy increased only to 83% when they agreed.
Our findings suggest that it is difficult to differentiate enchondroma from secondary chondrosarcoma in the foot. Concern for malignant change is warranted for cartilage bone tumors of the foot if they exceed 5 cm(2), or if they arise in the midfoot or hindfoot. In these cases, we recommend either biopsy or close clinical followup.
内生软骨瘤是足部骨骼最常见的良性肿瘤。该区域的软骨肉瘤相对罕见，由内生软骨瘤恶变而来的情况更是少见。与四肢骨骼的类似肿瘤不同，这两种肿瘤发生在足部时很难区分。
我们回顾了美国武装部队病理研究所（AFIP）放射学档案中所有内生软骨瘤及由内生软骨瘤恶变而来的软骨肉瘤（继发性软骨肉瘤）患者的病历和X线片，确定了那些肿瘤累及足部骨骼的患者。内生软骨瘤患者有755例，其中34例（4.8%）累及足部；继发性软骨肉瘤患者有340例，其中14例（4.1%）累及足部。我们比较了这两种病变的临床和影像学特征。我们还比较了观察者之间在诊断以及是否存在扇贝样改变、骨折、皮质破坏和矿化基质方面的差异。
大小和位置是区分这两种肿瘤的统计学显著变量（p = 0.03）。内生软骨瘤的平均大小为2.7 cm²。与前足的病变相比，发生在后足和中足的病变更有可能是恶性的。在比较观察者间的可靠性时，大多数分歧发生在基质的有无方面，检查者仅在51%的时间里意见一致。关于诊断，检查者的准确率分别为71%和80%。当他们意见一致时，准确率仅提高到83%。
我们的研究结果表明，足部的内生软骨瘤与继发性软骨肉瘤很难区分。如果足部软骨骨肿瘤超过5 cm²，或者发生在中足或后足，则有恶变的可能。在这些情况下，我们建议进行活检或密切的临床随访。
