Bone cancer photo

ABSTRACT

Purpose. To review cases of bone and soft tissue tumours of the feet managed at the Hyogo College of Medicine, Nishinomiya and Takarazuka Municipal Hospital, Takarazuka, Japan.

Methods. Retrospective analysis of 83 patient records treated for bone and soft tissue tumours of the feet between 1974 and 2000.

Results. There were 33 benign bone tumours, one primary malignant bone tumour, and 2 metastatic bone cancer. Marginal resection was performed in cases of osteochondroma and curettage in cases of other benign bone tumour. Despite below-knee amputation in the case of chondrosarcoma, the patient died because of pulmonary metastasis. Two patients with metastatic cancer also died, and 2 cases of osteochondroma and one of benign chondroblastoma recurred. There were 47 cases of soft tissue tumour. Treatment for benign soft tissue tumours was marginal resection; no cases recurred. In contrast, all patients with soft tissue sarcoma died after surgery. The majority of bone tumours were located in the toe and hindfoot areas, in the first and second decades of life, whereas soft tissue tumours occurred mainly in the midfoot area and in

patients aged between 20 and 50 years. The sex distribution was almost even for bone tumours (male: female ratio, 19:17), whereas about half as many males as females had soft tissue tumours (14:33).

Conclusion. Bone and soft tissue tumours of the feet are uncommon. Most bone tumours are chondrogenic, but differential diagnosis of malignant from benign disease is difficult and prognosis is poor. Management of benign tumours by marginal resection has good prognosis, whereas prognosis of soft tissue sarcomas is very poor.

Key words: bone tumor; soft tissue tumor; foot

INTRODUCTION

Bone and soft tissue tumours of the feet continue to present the clinician with one of the most difficult problems in medicine. These tumours are uncommon, but there have been very few reports of large series in the literature, and the epidemiology of these tumours is not well known. We reviewed the experience with bone and soft tissue tumours of the feet seen at the Hyogo College of Medicine and Takarazuka Municipal Hospital over a 26-year period.

MATERIALS AND METHODS

After reviewing about 900 cases of tumours of the locomotor system observed at Takarazuka Municipal Hospital, Takarazuka, and Hyogo College of Medicine, Nishinomiya, Japan, between 1974 and 2000, we identified 83 cases of bone and soft tissue tumours located in the feet.

The age and sex of the patients, and location and pathological diagnosis were obtained from hospital records for retrospective analysis. In this study, the location of the tumour was categorised as follows: toe area (more distal than the metatarsophalangeal joints), midfoot area (between the metatarsophalangeal joints and Chopart joint), and hindfoot area (proximal to the Chopart joint) of the foot.

RESULTS

Bone tumours

There were 33 benign bone tumours, one primary malignant bone tumour, and 2 metastatic bone tumours (Table 1). The majority of the benign tumours were chondrogenic (17 cases of exostosis, 7 of enchondroma, and 2 of benign chondroblastoma). Marginal resection was performed in cases of osteochondroma and curettage in cases of other benign tumour. Two cases of osteochondroma and one of benign chondroblastoma recurred.

Below-knee amputation was performed for one case of chondrosarcoma; the patient died because of pulmonary metastasis. Bone biopsy was performed in 2 cases of metastatic cancer; both patients died of the disease.

Case report

A 52-year-old man presented to the Hyogo College of Medicine in September 1985 with chondrosarcoma of the left talus, after having been admitted to another hospital for left ankle pain. Open biopsy of the left talus had been performed, and microscopic examination had revealed no malignant features (Fig. 1). The lesion had been curetted following bone grafting in July 1984. The initial diagnosis at the previous institution was benign chondroblastoma.

The patient was referred to our hospital for local recurrence of the tumour 5 months later. A plain X-ray taken in September 1985 showed collapse of the left talus and soft tissue mass (Fig. 2). Computed tomography confirmed soft tissue invasion of the tumour and destruction of the cortex of the talus (Fig. 3). A biopsy performed at our institution revealed atypical cells compatible with chondrosarcoma (Fig. 4). Although below-knee amputation was performed, the patient died another 5 months later.

The problem in this case was delay in the correct diagnosis. The diagnosis of chondrogenic tumour is, however, difficult by nature. Firstly, most chondrosarcomas occur around the hip joint; they are seldom found in the foot. Secondly, the cytological grade of malignancy does not always correlate with clinical behaviour. Hence, information of the tissue pattern is needed to distinguish malignant from benign chondrogenic tumours. Radiographic findings are also useful: destruction of the cortical bone, together with soft tissue invasion, is a likely indicator of a malignant tumour.

Soft tissue tumours

Among the 47 cases of soft tissue tumour in the feet were numerous types of soft tissue lesions (Table 2). Treatment for benign tumours was marginal resection; no case recurred. In contrast, all patients with soft tissue sarcoma died after surgery.

Comparison between bone and soft tissue tumours

The majority of bone tumours were located in the toe area (22 cases; 61%) and hindfoot area (12 cases; 33%), whereas soft tissue tumours occurred mainly in the midfoot area (18 cases; 45%) [Table 3]. Bone tumours (osteochondroma and solitary bone cyst) commonly occurred in the first and second decades of life (16 cases; 44%), while most soft tissue tumours (24 cases; 63%) occurred in the patients aged between 20 and 50 years (Table 4 and Fig. 5). The sex distribution was almost even for bone tumours (male: female, 19:17), whereas about half as many males as females had soft tissue tumours (14:33) [Fig. 6].

The majority of bone tumours that were located in the toe area were osteochondromas and enchondromas (20 cases; 91%). About half as many males as females had these tumours in the toe area (7:15), whereas 5 times as many males as females (10:2) were affected in the hind area (Table 3). In contrast, the mid-area was the predominant location for all groups of soft tissue tumour except giant cell tumour, and females were predominantly affected among all groups (Table 3).

DISCUSSION

Although the majority of bone tumours in our series were osteochondroma and enchondroma, osteoid osteoma was the most frequent lesion among the patients described by Casadei et al.1 followed by bone cyst. Osteochondroma, however, was not included as a true neoplasm (which does not match their criteria of true neoplasm) in their report. In their series, most bone cysts were treated conservatively, and bone cysts were not included in our data. We found no cases of osteoid osteoma in our study: this is the significant difference between our and their series and possible explanations are racial or different basis of diagnosis.

In our series, the mid-area of the foot was the least commonly affected area for bone tumours. The hindfoot was the more common site of bone tumour in the report of Casadei et al.1 If we excluded cases of osteochondroma as Casedei et al did, the hindfoot becomes the more commonly affected area than forefoot in our series. Thus the pattern of tumour locations is compatible between the 2 series.

In our series and that of Kirby et al.2 females had soft tissue tumour more commonly than did males. In our series, the mid-area was more commonly affected than the other parts. Ganglia were more commonly located in the report by Kirby et al. In our institution, the glanglia were commonly treated by just aspiration. Most ganglia operated on in our institutions were atypical and located in the plantar aspect of the foot, making preoperative diagnosis very difficult.

CONCLUSION

In our series, bone tumours were more commonly located in the forefoot and hindfoot, and was soft tissue tumours in the midfoot. Most bone tumours were chondrogenic. Chondrosarcoma was very rare, the differential diagnosis from the benign counterpart was difficult, and the prognosis was poor. Management of benign tumour by marginal resection was associated with a good prognosis, whereas prognosis of soft tissue sarcomas was very poor.

ACKNOWLEDGMENT

The authors thank Dr M Nakajima for providing the photo-micrograph of the presented chondrosarcoma case in this paper.

REFERENCES

1. Casadei R, Ferraro A, Ferruzzi A, Biagini R, Ruggieri P. Bone tumors of the foot: epidemiology and diagnosis. Chir Organi Mov

2. Kirby EJ, Shereff MJ, Lewis MM. Soft-tissue tumors and tumor-like lesions of the foot. An analysis of eighty-three cases. J Bone Surg Am 1989;71:621-6.

G Kinoshita, M Matsumoto, T Maruoka, T Shiraki, K Tsunemi