Australas Radio1 1992; 36: 257-259

Multifocal Metachronous Osteogenic Sarcoma GEORGE VERGHESE, M.B., B.S., D.Ortho. Registrar Department of Orthopaedic Surgery V. SARADA, M.D. Lecturer Department of Pathology G.D. SUNDARARAJ, D.Ortho, MSOrtho, M.Ch.Ortho, F.A.C.S. Professor and Head Department of Orthopaedic Surgery SUSHIL M. CHANDI, M.D., Ph.D. Professor Department of Pathology Christian Medical College and Hospital, Vellore, 632 004 India

INTRODUCTION Osteogenic sarcoma, the most common malignant skeletal tumour, is rarely found in the tarsal bones, having a reported incidence of less than one percent in this location (1). Multifocal osteogenic sarcoma is also a rare entity. The following is a case report of a patient with osteogenic sarcoma of the tarsal bones who subsequently developed osteoblastic osteosarcomatous lesions in the skull and fibula. CASE REPORT A 16 year old boy presented with an ulcerated swelling of the left foot of 7 months duration, the onset of which he associated with a trivial injury. Pain was not a major feature, but an increase in size of the swelling had affected his gait. One of two incisional biopsies of the mass taken elsewhere was reported as chondrosarcoma. The report of the other biopsy - . was not available. On examination, the patient had an ill-defined 15 x 10 cm swelling on the dorsum of the left foot which also involved its lateral, medial and plantar

Address for correspondence: Dr George Verghese Registrar Department of Orthopaedic Surgery Christian Medical College and Hospital, Vellore, 632 004 India

Australasian Radiology. Vol. 36, No. 3.August, 1992

FIGURE 1 - X-ray of the left foot showing an ill-defined osteosclerotic growth in the region of the

aspects. In the stretched skin over it, there were two ulcers and engorged veins. The swelling was fixed to the underlying tarsal bones and varied in consistency from cystic to firm in areas. The ankle joint was clinically normal. A provisional diagnosis of osteogenic sarcoma was made. A plain X-ray of the left foot showed an expansile osteosclerotic growth arising from the tarsal bones, the metatarsals being free (Figure 1). Chest radiographs were normal. The alkaline phosphatase level was 526 u/l and ESR 54mm in 1 hour. The tissue sections on the second biopsy taken elsewhere were reviewed and reDorted as consistent with osteosardoma. A below knee amputation of the left leg was performed.

Macroscopic examination showed a tumour involving almost 2/3 of the foot extending from the ankle joint proximally, to the metatarsals distally (Figure 2). The tumour was bony hard and cut with a gritty feel. The tumour margins were irregular and indistinct. The metatarsals and ankle joint appeared grossly free of tumour. On microscopy, sections from the tumour showed features of an osteogenic sarcoma with anaplastic stromal cells and evidence of osteoid production by the tumour cells (Figure 3). The distal bony and soft tissue surgical margins were free of tumour infiltration. Submitted for publication on: 14th May, 1991 Resubmined for publication on:23rd December,1991 Accepted for publication on: 18thFebruary, 1992

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FIGURE 2 - Osteosarcoma of the left foot predominantly involving and destroying the tarsal bones.

FIGURE 4 - CT scan showing hyperdense osteoblastic lesion in the sphenoid sinus extending towards the cavernous sinus.

The post operative period was uneventful and the surgical wound healed completely. One month following radical surgery, the patient complained of progressive diminution of vision and a squint involving the left eye. A CT scan of the head showed a hyperdense mass involving the sphenoidal bones, the posterior part of the left nasal cavity and the cavernous sinus, with thickening of the left optic nerve, suggestive of an osteoblastic secondary tumour deposit (Figure 4). A bone scan showed an increased uptake by the lesion in the skull. A biopsy of the secondary lesion by a transnasal approach was performed and was reported as "metastatic osteosarcoma" (Figure 5 ) . Shortly thereafter, the patient complained of pain in the amputation

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FIGURE 3 - Pleomorphic osteoblasts and intervening trabeculae of osteoid characteristic of osteosarcoma (H & E, x 500).

FIGURE 5 - Metachronous osteosarcoma deposit in the sphenoid sinus. (H & E, x 750).

stump. A clinical examination revealed a swelling arising from the proximal fibula and radiographs of the stump showed patchy osteoblastic lesion arising from the upper fibula (Figure 6). A bone scan showed a circumscribed area of increased uptake in the fibula suggestive of an osteoblastic lesion (Figure 7). Before a confirmatory biopsy could be obtained or a chemotherapeutic regimen implemented, the patient was discharged against medical advice at his request and was lost to follow-up.

DISCUSSION Most osteogenic sarcomas present as solitary lesions. Multifocal osteogenic sarcomas are rare (1-2%), and are described as synchronous osteogenic sarcoma when multiple

lesions present within six months of each other and metachronous osteogenic sarcoma when the interval between the primary and secondary lesions is more than six months. Amstutz differentiates the synchronous variety into two types, type 1 seen in young patients and type 2 seen in adults (1). Some workers including Mirra & Amstutz believe that multifocal metachronous lesions which develop in patients with osteogenic sarcoma treated with chemotherapy, actually represent metastatic disease (2). Proof of such lesions being metastatic is however extremely difficult to establish, because metastatic lesions do not demonstrate specific radiologic or histologic features. Mahoney holds the view that only metachronous lesions Australasian Radiology, Vol. 36, No. 3,August, 1992

MULTIFOCAL METACHRONOUS OSTEOGENIC SARCOMA

RGURE 6 - X-ray of the fibula showing patchy osteoblastic lesion arising from the upper fibula.

developing within 24 months are metastatic (3). In this case the lesion in the foot preceded the lesions in the sphenoid sinus and fibula by seven months. Radiographs of the chest however revealed no pulmonary spread. The authors therefore present this as a case of multifocal osteogenic sarcoma of the metachronous variety.

Australasian Radiology, Vol. 36, No. 3. August. 1992

FIGURE 7 - Bone scan showing increased uptake in the fibula.

REFERENCES 1.

Mirra JM. Osseous turnours of intramedullary origin in Mirra JM. Picci P and Gold RH. Bone tumours Vol. 1 Philadelphia London, Lea & Febiger 1989;

2.

Amstutz HC. Multiple osteogenic sarcoma - metastatic or multicentric? Cancer 1969;

143-438. 24: 923 - 931.

3.

Mahoney JP, Spanier S , Morris JL. Multifocal osteogenic sarcoma - a case report and review of the literature. Cancer 1979; 44: 1987-1907.

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Multifocal metachronous osteogenic sarcoma.

Australas Radio1 1992; 36: 257-259 Multifocal Metachronous Osteogenic Sarcoma GEORGE VERGHESE, M.B., B.S., D.Ortho. Registrar Department of Orthopaed...
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